Postoperative cardiothoracic ratio on the first postoperative day is a predictor of postoperative pleural effusion drainage following hepatectomy

Postoperative cardiothoracic ratio on the first postoperative day is a predictor of postoperative pleural effusion drainage following hepatectomy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Postoperative cardiothoracic ratio on the first postoperative day is a predictor of postoperative pleural effusion drainage following hepatectomy Akimasa Sakamoto, Katsunori Sakamoto, Mikiya Shine, Mio Uraoka, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2807394/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Although several preoperative risk factors for postoperative pleural effusion (POPE) after hepatectomy have been reported, few postoperative predictors have been investigated. We aimed to examine risk factors for clinically relevant POPE (CR-POPE) and whether cardiothoracic ratio (CTR) could be a predictive factor. Methods Participants in this retrospective investigation comprised 382 patients who underwent hepatectomy between January 2012 and December 2021. Perioperative characteristics that were considered potential risk factors for CR-POPE were evaluated. CR-POPE was defined as having undergone thoracentesis or thoracic drain placement. Results Patients were divided into a CR-POPE group ( n = 38; 10.0%) and a non-CR-POPE group ( n = 344; 90.0%). The CR-POPE group showed significantly higher intraoperative infusion volume ( P < 0.001) and lower intraoperative urine volume ( P = 0.015). In multivariate analysis, abdominal incision with a reversed L-shape or inverted T-shape (odds ratio [OR] = 3.07, P = 0.023], estimated blood loss > 772 g (OR = 2.71, P = 0.049), diaphragm incision (OR = 8.31, P = 0.008), major postoperative complications excluding CR-POPE (OR = 7.99, P 80 mL/kg (OR = 4.80, P = 0.007) and CTR on postoperative day (POD)1 > 59.0% (OR = 4.34, P = 0.001) were all independently associated with occurrence of POPE. Conclusion We clarified risk factors for CR-POPE following hepatectomy. The occurrence of CR-POPE might be predictable from the CTR on POD1. cardiothoracic ratio hepatectomy pleural effusion postoperative complication Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Liver resection is a widely accepted curative treatment for malignant and benign diseases of the liver. Several postoperative complications after liver resection have been reported, such as intra-abdominal hemorrhage, intra-abdominal infection, bile leakage, ascites effusion, and pleural effusion (PE). Postoperative pleural effusion (POPE) is one of the most common complications after liver resection. The incidence of POPE following hepatectomy has been reported as 18–71% [ 1 – 3 ]. The clinical presentation of POPE varies widely, from mild asymptomatic cases to severe cases with respiratory failure. POPE is rarely fatal, but sometimes necessitates thoracentesis or thoracic drain placement, as POPE is an important cause of postoperative hypoxia, which may result in liver failure [ 1 ]. POPE can thus prolong hospitalization and increase costs [ 2 ]. Furthermore, occurrence of POPE not only affects short-term outcomes, but can also delay postoperative rehabilitation and subsequent disease treatment. In patients with hepatocellular carcinoma, POPE has been reported as an independent risk factor for recurrence and patient death [ 2 ]. Identification of risk factors for POPE is therefore important. Cardiothoracic ratio (CTR) is a simple value to evaluate heart size from chest radiographs [ 4 ]. CTR has been found to offer a useful prognostic factor in several diseases. In cardiovascular disease, CTR is used to indicate cardiomegaly and is associated with heart failure [ 5 , 6 ]. A higher CTR is associated with higher mortality among patients on hemodialysis [ 7 , 8 ]. Higher CTR also indicates pulmonary venous congestion [ 9 ]. However, to best of our knowledge, no association between CTR and POPE after hepatectomy has been reported. We investigated risk factors for POPE and examined whether CTR could allow early detection of POPE. Material And Methods Patients Participants in this retrospective study comprised 382 consecutive patients who had undergone hepatectomy (including both with/without biliary reconstruction followed by extrahepatic bile duct resection) for malignant or benign disease between January 2012 and December 2021 at Ehime University Hospital. Donors and recipients of liver transplantation as well as patients who had received placement of an intraoperative thoracic drainage tube due to accidental thoracotomy were excluded. Data on background characteristics, perioperative laboratory data, perioperative clinical data, pathological findings, and CTR were collected from medical records. This protocol was reviewed and approved by the institutional ethics committee of Ehime University Hospital in 2022. All participants, including retrospectively registered patients or their guardians, verbally consented to the use of their medical information for scientific research (approval no. EUH2205008). Operative Procedures And Perioperative Management Indications for surgery and surgical procedures were decided by a multidisciplinary team. Mobilization of the liver was performed only when required to resect a tumor safely. Patients essentially underwent intermittent hepatic pedicle occlusion during parenchymal dissection. The liver parenchyma was transected using a Cavitron ultrasonic surgical aspirator (Integra Lifesciences Corporation, Plainsboro, NJ, USA) and electric cautery equipped with channels for water dripping. Vessels that appeared in transected sections were generally ligated. Stumps of hepatic or portal veins were sutured using non-absorbable monofilament suture or divided using a linear stapler. One or two closed suction drainage tubes were usually placed close to the cut surface of the liver Winslow’s foramen according to the preference of the operator. Regarding postoperative management, patients with hypoxia or dyspnea for whom PE could be drained safely under computed tomography (CT) or ultrasound (US) guidance was one of the criteria for PE drainage. Asymptomatic hypoxia or assumption of worsened dyspnea with > 500 mL of PE on CT or US was another criterion. In-out balance was calculated as the infusion volume minus urine volume minus drain output on postoperative day (POD)1. Albumin was transfused when serum albumin value was < 2.5mg/dL in early postoperative phase or to maintain appropriate blood pressure. Postoperative complications were defined according to the Clavien–Dindo classification, and events of grade III or above were defined as major complications. POPE of grade III (thoracentesis or thoracic drain placement) or above was defined as clinically relevant POPE (CR-POPE) [ 10 ]. Calculation Of Ctr And Ct Volumetry For Pope CTR was calculated as the ratio of the maximal horizontal diameter of the heart to the maximal diameter of the thoracic wall on a chest radiograph (Fig. 1 ). Preoperative chest radiographs were taken in a standing position within 1 month before surgery. Postoperative chest radiographs in a supine position were taken in the operating room immediately postoperatively and in the intensive care unit the next morning. Postoperative chest and abdominal CT were taken around 1 week after surgery in most patients. Estimated POPE volume was calculated using 3-dimensional imaging software (SYNPASE VINCENT medical imaging system; Fujifilm Medical, Tokyo, Japan) (Fig. 2 ). Estimated POPE volume was measured before thoracentesis in the CR-POPE group. Statistical analysis All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS®) for Windows® (v.24.0; SPSS, Chicago, IL, USA). Longitudinal trends between CTR and estimated POPE volume were calculated using Spearman ρ correlations. Continuous variables were compared using Mann–Whitney U tests and are presented as medians with ranges. Optimal cut-offs for CTR and other risk factors were determined using receiver operating characteristic (ROC) curve analysis or standard cut-offs. Categorical variables were compared using χ 2 or Fisher’s exact tests and are presented with ratios. Significant variables on univariate analyses were included in multivariate analyses with stepdown logistic regression and likelihood tests. Regression models were calibrated using Hosmer–Lemeshow tests. Significance was defined at the level of P < .05. Results Univariate analysis for CR-POPE Of the 382 patients who underwent hepatectomy, 38 patients (10.0%) had CR-POPE. Thirty-seven patients had right-sided POPE and one had left-sided POPE. Median time from hepatectomy to drainage of POPE was 6 days (range, 2–35 days). Median volume of pleural fluid drained on the day of thoracentesis was 732 mL (range, 160–2,150 mL). Patient characteristics are summarized in Table 1 . The CR-POPE group showed higher preoperative total serum bilirubin level. Preoperative CTR, preoperative cardiac function and respiratory function did not differ significantly between groups. Table 1 Preoperative factors Non-CR-POPE n = 344 CR-POPE n = 38 P Sex, male 254 (73.8%) 29 (76.3%) 0.741 Age, years 70 (26–89) 72 (41–80) 0.793 Body mass index, kg/m 2 23.8 (15.4–39.8) 23.8 (17.2–32.0) 0.740 Comorbidities Diabetes mellitus 111 (32.3%) 9 (23.7%) 0.295 Hypertension 194 (56.4%) 23 (60.5%) 0.626 Chronic kidney disease 16 (4.7%) 3 (7.9%) 0.290 Cardiovascular disease 50 (14.5%) 6 (15.8%) 0.836 Previous hepatectomy 66 (19.2%) 3 (8.6%) 0.086 Chemotherapy 76 (22.1%) 5 (13.1%) 0.201 RFA 44 (12.8%) 3 (7.9%) 0.601 TACE 86 (24.1%) 6 (15.8%) 0.249 Blood biochemistry Hemoglobin, g/dL 12.9 (7.9–19.5) 12.6 (7.9–16.2) 0.938 Platelet, 10 4 /µL 18.8 (4.5–64.1) 17.6 (8.0-56.5) 0.567 Total bilirubin, mg/dL 0.6 (0.2–22.8) 0.8 (0.3–10.0) 0.006 Albumin, g/dL 3.8 (2.5–5.2) 3.8 (2.6–4.7) 0.606 Creatinine, mg/dL 0.80 (0.20–8.68) 0.82 (0.41–6.16) 0.451 PT-INR 1.00 (0.83–2.21) 1.00 (0.84–1.29) 0.555 ICGR15, % 12 (1–48) 10 (2–25) 0.06 Echocardiography LVDd, mm 45.6 (28.2–65.0) 26.9 (40.4–56.0) 0.105 LVDs, mm 28.0 (17.0–46.0) 29.0 (20.0-40.1) 0.203 LVEF, % 66.7 (44.2–83.4) 66.2 (43.5–78.0) 0.707 LAD, mm 36.0 (17.2–51.0) 36.1 (25.1–59.0) 0.980 Spirometry %VC, % 108 (39–151) 102 (65–129) 0.062 %FEV 1.0 , % 76 (27–100) 76 (54–81) 0.663 Child-Pugh 0.647 A 320 (93.0%) 34 (89.5%) B 23 (6.7%) 4 (10.5%) C 1 (0.3%) 0 (0.0%) CTR, % 47.0 (35.0-60.5) 48.6 (40.1–67.1) 0.065 RFA, radiofrequency ablation; TACE, transcatheter arterial chemoembolization; PT-INR, prothrombin time-international normalized ratio; ICGR15: indocyanine green retention rate at 15 min; LVDd, left ventricular diameter at end-diastole; LVDs: left ventricular diameter at end-systole; LVEF: left ventricular ejection fraction; LAD: left atrial dimension; %VC: vital capacity percentage; %FEV1.0: forced expiratory volume in 1 s as a percentage of forced vital capacity; CTR, cardiothoracic ratio; CR-POPE, clinically relevant postoperative pleural effusion. In terms of intraoperative variables, type of abdominal incision, prolonged duration of hepatic pedicle occlusion, higher estimated blood loss, greater frequency of red blood cell transfusion, higher infusion volume, lower urine volume, greater number of resected liver segments, biliary reconstruction, and diaphragm incision were all associated with occurrence of CR-POPE (Table 2 ). Table 2 Intraoperative factors Non-CR-POPE n = 344 CR-POPE n = 38 P Abdominal incision < 0.001 Laparoscopy 95 (27.6%) 0 (0.0%) Median 33 (9.6%) 1 (2.6%) Reversed L-shape 151 (43.9%) 27 (71.1%) Inverted T-shape 66 (18.9%) 10 (26.3%) Hepatic pedicle occlusion time, min 53 (0-240) 61 (0-274) 0.020 Operation time, min 388 (87 − 1,094) 427 (170–990) 0.372 Estimated blood loss per BW, g/kg 6.9 (0-61.1) 21.3 (1.2-109.2) < 0.001 Red blood cell transfusion 93 (27.0%) 26 (68.4%) < 0.001 Intraoperative infusion volume per BW, mL/kg 63.2 (15.7-163.7) 109.2 (54.5-264.4) < 0.001 Intraoperative urine volume per BW, mL/kg 8.8 (0-58.2) 13.6 (0-64.4) 0.016 Surgical site on S7 or S8 154 (44.8%) 20 (52.6%) 0.393 Number of resected segments 2 (0–6) 3 (0–6) < 0.001 Biliary reconstruction 33 (9.6%) 14 (36.8%) < 0.001 Diaphragm incision 14 (4.1%) 5 (13.2%) 0.031 BW, body weight; CR-POPE, clinically relevant postoperative pleural effusion. Regarding postoperative variables, the CR-POPE group showed a higher CTR on both POD0 and POD1, higher infusion volume on POD1, higher urine volume on POD1, prolonged duration of hospitalization and a greater frequency of major postoperative complications excluding POPE (Table 3 ). Table 3 Postoperative factors Non-CR-POPE n = 344 CR-POPE n = 38 P Hospital stays, days 13 (3-163) 40 (7-164) < 0.001 Major postoperative complications excluding POPE 43 (12.5%) 25 (65.8%) < 0.001 Bile leakage 18 (5.2%) 7 (18.4%) 0.007 Intra-abdominal hemorrhage 3 (0.9%) 3 (7.9%) 0.015 Intra-abdominal infection 10 (2.9%) 8 (21.1%) < 0.001 Portal vein thrombosis 0 (0%) 2 (5.2%) 0.010 Liver failure 2 (0.6%) 4 (10.5%) 0.001 CTR on POD0, % 54.9 (41.6–67.6) 56.4 (45.4–65.0) 0.045 CTR on POD1, % 55.5 (42.7–66.7) 59.3 (49.4–67.8) < 0.001 Infusion volume on POD1 per BW, mL/kg 38.5 (8.5–95.2) 49.0 (18.7–74.3) < 0.001 Urine volume on POD1 per BW, mL/kg 25.6 (0-102.1) 17.3 (0-52.3) < 0.001 In-out balance on POD1 per BW, mL/kg 9.3 (-62.1-60.1) 20.2 (14.1–50.2) < 0.001 Pathological findings 0.004 Hepatocellur carcinoma 174 (50.6%) 14 (36.8%) Cholangiocarcinoma 48 (14.0%) 14 (36.8%) Metastatic tumor 106 (30.8%) 8 (21.1%) Other 16 (4.7%) 2 (5.3%) Cirrhosis of resected liver, F4 60 (17.4%) 8 (21.1%) 0.581 Cirrhosis was pathologically diagnosed according to the Inuyama classification. CTR, cardiothoracic ratio; POD, postoperative day; CR-POPE, clinically relevant postoperative pleural effusion. Correlation Between Ctr On Pod1 And Estimated Pope Volume Estimated POPE volume was evaluated from CT images among 250 patients at a median of 7 postoperative days (range, 1–16 days). Figure 3 shows scatter plots of CTR on POD1 and estimated POPE volume. Estimated POPE volume correlated with CTR on POD1 (r = 0.175; 95% confidence interval [CI], 0.055–0.290; P = 0.005). Calculation Of Optimal Ctr Cut-off The optimal cut-off was determined using ROC curve analysis (Fig. 4 ). Area under the ROC curve for CTR on POD1 was 0.678 (95%CI, 0.580–0.775) and the most appropriate cut-off was determined to be 59.0. This value offered 57.9% sensitivity and 80.5% specificity. Multivariate Analysis For Cr-pope Factors that showed significant correlations with CR-POPE on univariate analyses were entered into the multivariate analysis (Table 4 ). On multivariate analysis, abdominal incision with a reversed L-shape or inverted T-shape (odds ratio [OR], 3.07; 95%CI, 1.17–8.04; P = 0.023), estimated blood loss > 772 g (OR, 2.71; 95%CI, 1.01–7.28; P = 0.049), diaphragm incision (OR, 8.31; 95%CI, 1.75–39.45; P = 0.008), major postoperative complications excluding POPE (OR, 7.99; 95%CI, 3.13–20.41; P 80 mL/kg (OR, 4.8; 95%CI, 1.55–14.86; P = 0.007) and CTR on POD1 > 59.0% (OR, 4.34; 95%CI, 1.77–10.66; P = 0.001) were identified as independent risk factors for CR-POPE (Table 4 ). Table 4 Uni- and multivariate analyses to identify predictors of clinically relevant postoperative pleural effusion Univariate Multivariate Odds ratio (95% CI) P Odds ratio (95% CI) P Total bilirubin 33 min 1.95 (0.95–3.99) 0.067 Estimated blood loss > 772 g 9.37 (4.27–20.58) < 0.001 2.71 (1.01–7.28) 0.049 Red blood cell transfusion 5.82 (2.82–12.02) 3 3.23 (1.63–6.41) 0.001 0.77 (0.22–2.73) 0.684 Biliary reconstruction 5.50 (2.60–11.6) < 0.001 0.58 (0.09–3.66) 0.560 Diaphragm incision 3.57 (1.21–10.54) 0.021 8.31 (1.75–39.45) 0.008 Major postoperative complications excluding POPE 13.46 (6.41–28.28) < 0.001 7.99 (3.13–20.41) 80 mL/kg 11.44 (4.87–26.86) 20 mL/kg 3.79 (1.91–7.52) 59.0% 5.40 (2.70-10.83) < 0.001 4.34 (1.77–10.66) 0.001 POPE, postoperative pleural effusion; BW, body weight; CTR, cardiothoracic ratio; POD, postoperative day; CI, confidence interval. Discussion POPE is one of the most common postoperative complications after liver resection. Previous studies have reported various risk factors for POPE, including age, body mass index, chronic obstructive pulmonary disease, resection site of liver, resected liver weight, operative time, and transfusion [ 2 , 3 , 11 , 12 ]. The present study revealed abdominal incision, blood loss, diaphragm incision, and intraoperative infusion volume as independent risk factors for CR-POPE. CTR on POD1 was identified as an independent predictor. Moreover, estimated POPE volume using CT volumetry correlated with CTR on POD1. CT volumetry for POPE is a novel approach that allows continuous quantification of volume. Generally, PE is classified as exudative (due to imbalances in hydrostatic or oncotic pressures) or transudative (inflammatory) effusion based on the pathophysiology [ 13 , 14 ]. POPE following coronary artery bypass surgery is classified as exudative, but POPE following hepatobiliary surgery is uncertain. PE after liver resection might have a dual etiology of both hypoalbuminemia with cirrhosis and direct inflammatory responses to the thoracic cavity. Clinically, most POPE tends to arise in the right-sided pleural cavity. Risk factors including abdominal incision, resection site, incision in the diaphragm to reach the liver, and tumor invasion to the diaphragm, indicated the influence of local inflammation. Another strongly associated factor, was postoperative complications excluding POPE, such as bile leakage or cut-end abscess, which demonstrate local or systemic inflammation, leading to secondary POPE. However, since biochemical data for PE were lacking, it remains unclear whether POPE is a result of other complications or a sign of complications, or both. Postoperative hypoalbuminemia is also reportedly associated with POPE [ 15 ]. We therefore investigated the impact of hemodynamics on CR-POPE and whether CTR could predict CR-POPE. Excessive infusion volume has been reported to worsen postoperative pulmonary function [ 16 , 17 ]. Surgical invasion has direct effects on fluid retention. Plasma volume decreases with general anesthesia alone [ 18 ]. Under such conditions of intraoperative hemodynamics, fluid distributes into the interstitium. A Danish multicenter randomized trial showed that a higher volume of intraoperative fluid infusion resulted in sodium retention and weight gain for 2–3 days after surgery, then declined [ 19 ]. This accumulation of fluid and delayed clearance may cause excessive intravascular volume loading, leading to pulmonary edema and PE. Postoperative enlargement of the CTR is a sign of overloading and cardiomegaly. In the present study, the CR-POPE group showed a significantly higher infusion volume and lower urine volume intraoperatively. Furthermore, infusion volume correlated with both estimated POPE volume and CTR. This demonstrated that an excessive fluid balance resulted in POPE. Perioperative fluid management should be administered appropriately according to blood loss [ 20 ]. However, if the operation takes a longer time, total infusion volume will be correspondingly higher. In hepatobiliary surgery, bleeding from the liver parenchyma sometimes requires massive infusion or transfusion. Attention must be paid to the infusion volume, particularly in patients with poor cardiac, respiratory, or renal function or the elderly. Adjusting postoperative infusion volume and early administration of diuretics could inhibit excessive overloading. On the other hand, goal-directed fluid therapy that requires perioperative fluid restriction has become widespread, and is being trialed for liver resection [ 21 – 23 ]. Transition of surgery and anesthesia might affect the occurrence of postoperative complications. Actually, the present cohort showed a lower incidence of CR-POPE than previous reports [ 1 – 3 ]. In the present study, abdominal incision was an independent factor. Recent progress in minimally invasive surgery has led to increases in laparoscopic surgery [ 24 ]. Conversely, the occurrence of comorbidities has decreased in laparoscopic surgery [ 25 ]. The higher estimated blood loss, transfusion and biliary reconstruction in the CR-POPE group may support secondary POPE due to other postoperative complications. In fact, postoperative complications were independently associated with CR-POPE. The CTR is a well-established value in the clinical setting for evaluating cardiac morphology radiologically [ 4 ]. Rayner et al. reported that CTR on cardiac radiographs correlated with left ventricular mass on echocardiography [ 26 ]. Previous studies have reported the prognostic utility of the CTR. A larger CTR could be a predictive marker of sudden death in patients with chronic heart failure and long-term survival rate in patients with hemodialysis [ 5 , 6 ]. Those studies demonstrated that hemodynamics had an effect on CTR. Further, a larger CTR is a prognostic factor for short-term postoperative outcomes in cardiac surgery [ 27 , 28 ]. However, no investigations with non-cardiac surgery have been conducted and this is the first to show an impact of CTR on postoperative outcomes. This retrospective study showed several limitations. Imaging conditions for chest radiography might vary depending on the status of the patient. Postoperative abdominal pain alters respiratory functions. Patients with chronic obstructive pulmonary disease often have a smaller CTR, whereas patients with chronic heart failure have a larger CTR. The advantage of CTR measurement is that this simple method can be applied using chest radiographs. Several advanced imaging modalities have emerged recently, such as CT, magnetic resonance imaging, and radioisotope imaging [ 29 ]. However, radiographs cannot replace these options because of the convenience, speed, and low exposure. Radiographs can be taken anywhere using mobile equipment without patient transfer. Although the rate of increase in CTR from pre- to postoperatively is also useful, here we offer a use for postoperative CTR on POD1 with clinical utility. In the present study, the properties of PE using pleural fluid were not examined and further investigations should be conducted in the future. Conclusion The present study revealed CTR > 59.0% is one of the risk factors of CR-POPE following hepatectomy. Larger CTR may facilitate appropriate postoperative management. Declarations Authors’ Contributions: AS and KS contributed to the study conception and design. NF, MS, MU, TN, TU, KT, KS, KO, and YT performed surgeries and collected data. AS and KS wrote the first draft of the article. KO and YT contributed to the review and critical revision of the article. All authors have approved the final version of the manuscript. Conflicts of Interest: The authors declare no conflicts of interest regarding the publication of this paper. Funding: No funding was received. ORCID AS, 0000-0001-8042-1486, KS, 0000-0002-6431-0011, MU, 0000-0001-7517-5612, TN, 0000-0002-7635-9995, MH, 0000-0001-9642-4155, KT, 0000-0002-6077-5428, NF, 0000-0001-6076-6516, KO, 0000-0002-5672-6308, YT, 0000-0001-9743-1840 References Nitta H, Mitsuura C, Shiraishi Y, et al (2020) Predictive model for postoperative pleural effusion after hepatectomy. Ann Gastroenterol Surg 5:373-380 https://doi.org/10.1002/ags3.12417 Nobili C, Marzano E, Oussoultzoglou E, et al (2012) Multivariate analysis of risk factors for pulmonary complications after hepatic resection. Ann Surg 255:540-550 https://doi.org/10.1097/SLA.0b013e3182485857 Uchiyama H, Harimoto N, Itoh S, Yoshizumi T, Ikegami T, Maehara Y. Pleural Effusion After Hepatectomy for Hepatocellular Carcinoma: Risk Factor Analyses and Its Impact on Oncological Outcomes. 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Int J Cardiol 106:373-81 https://doi.org/10.1016/j.ijcard.2005.02.030 Jiang L, Chen WG, Geng QS, et al (2019) The cardiothoracic ratio: a neglected preoperative risk-stratified method for patients with rheumatic heart disease undergoing valve replacement surgery. Eur J Cardiothorac Surg 55:511-517 https://doi.org/10.1093/ejcts/ezy255 McAdams HP, Samei E, Dobbins J 3rd, Tourassi GD, Ravin CE (2006) Recent advances in chest radiography. Radiology 241:663-683 https://doi.org/10.1148/radiol.2413051535 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2807394","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":191785586,"identity":"6e1d4bef-6687-4e50-8a81-cc4994976993","order_by":0,"name":"Akimasa Sakamoto","email":"data:image/png;base64,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","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Akimasa","middleName":"","lastName":"Sakamoto","suffix":""},{"id":191785587,"identity":"f3e767af-6b3d-4f85-9a67-8e391c72f6ae","order_by":1,"name":"Katsunori Sakamoto","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Katsunori","middleName":"","lastName":"Sakamoto","suffix":""},{"id":191785588,"identity":"4ccdf582-f10f-4c13-86d7-05cc6405abf1","order_by":2,"name":"Mikiya Shine","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Mikiya","middleName":"","lastName":"Shine","suffix":""},{"id":191785589,"identity":"29c59b85-a240-436d-b641-dfc528e33e4e","order_by":3,"name":"Mio Uraoka","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Mio","middleName":"","lastName":"Uraoka","suffix":""},{"id":191785590,"identity":"f07b434d-b734-41ee-a057-cc4c5a038b8c","order_by":4,"name":"Tomoyuki Nagaoka","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tomoyuki","middleName":"","lastName":"Nagaoka","suffix":""},{"id":191785591,"identity":"033f6e78-89b7-4d3b-8be8-97958be6e514","order_by":5,"name":"Masahiko Honjo","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Masahiko","middleName":"","lastName":"Honjo","suffix":""},{"id":191785592,"identity":"25188963-fa0c-4785-8198-5195b6aeae35","order_by":6,"name":"Kei Tamura","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kei","middleName":"","lastName":"Tamura","suffix":""},{"id":191785593,"identity":"45336267-ec7c-4c00-8eb5-2a26ece36fbe","order_by":7,"name":"Naotake Funamizu","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Naotake","middleName":"","lastName":"Funamizu","suffix":""},{"id":191785594,"identity":"f8a809f2-4c44-4ea5-859a-27a8f489a404","order_by":8,"name":"Kohei Ogawa","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kohei","middleName":"","lastName":"Ogawa","suffix":""},{"id":191785595,"identity":"653722b4-f3f6-478b-a3fb-56993298e807","order_by":9,"name":"Yasutsugu Takada","email":"","orcid":"","institution":"Ehime University Graduate School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yasutsugu","middleName":"","lastName":"Takada","suffix":""}],"badges":[],"createdAt":"2023-04-12 15:14:23","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2807394/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2807394/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":35879496,"identity":"5e2bf59f-5b40-4f47-888f-843cf516bba6","added_by":"auto","created_at":"2023-04-17 14:46:22","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":254712,"visible":true,"origin":"","legend":"\u003cp\u003eCardiothoracic ratio was calculated as the ratio of the maximal horizontal diameter of the heart (C1 plus C2) to the maximal diameter of the thoracic wall (T1 plus T2) on a chest radiograph.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-2807394/v1/b5ad23d930673ee169b970de.png"},{"id":35879495,"identity":"5789515f-b96a-4d09-a764-d81a2b90c614","added_by":"auto","created_at":"2023-04-17 14:46:22","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":412385,"visible":true,"origin":"","legend":"\u003cp\u003eComputed tomography images were transferred from the Picture Archiving and Communication System (PACS) to the SYNPASE VINCENT medical imaging system. We traced the border of pleural effusion using the free-ROI manual method on axial images.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-2807394/v1/b42eb1141f4d27d7e9ed3e4f.png"},{"id":35880393,"identity":"72cccc30-1c05-4d37-ad31-1f07f0319d48","added_by":"auto","created_at":"2023-04-17 14:54:22","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25337,"visible":true,"origin":"","legend":"\u003cp\u003eScatter plot of estimated pleural effusion (PE) volume. Estimated PE volume was calculated using computed tomography (CT) volumetry (Fig. 1). Postoperative CT was performed around 1 week after surgery. In the clinically relevant postoperative PE (CR-POPE) group, estimated PE volume was evaluated before thoracentesis. The CR-POPE group is shown as cross marks and the non-CR-POPE group as circles. Positive correlations are evident between amount of PE and cardiothoracic ratio.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-2807394/v1/8f637c9b6d3d36c021d95c6d.png"},{"id":35879494,"identity":"6a4eb099-cfc2-40ce-9eff-5e676f1a4ab0","added_by":"auto","created_at":"2023-04-17 14:46:22","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":25078,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver operating characteristic (ROC) curve analysis of cardiothoracic ratio. ROC curve analysis estimates a cardiothoracic ratio of 59.0% as the optimal cut-off for predicting postoperative pleural effusion.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-2807394/v1/ee4add60177974e21704d02e.png"},{"id":38389365,"identity":"44072b31-c3e1-4a0e-9230-eeefe7d1d776","added_by":"auto","created_at":"2023-06-12 10:44:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":970819,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2807394/v1/3b00e1db-eff7-49c4-a16a-5d56cd41941a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Postoperative cardiothoracic ratio on the first postoperative day is a predictor of postoperative pleural effusion drainage following hepatectomy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eLiver resection is a widely accepted curative treatment for malignant and benign diseases of the liver. Several postoperative complications after liver resection have been reported, such as intra-abdominal hemorrhage, intra-abdominal infection, bile leakage, ascites effusion, and pleural effusion (PE).\u003c/p\u003e \u003cp\u003ePostoperative pleural effusion (POPE) is one of the most common complications after liver resection. The incidence of POPE following hepatectomy has been reported as 18\u0026ndash;71% [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The clinical presentation of POPE varies widely, from mild asymptomatic cases to severe cases with respiratory failure. POPE is rarely fatal, but sometimes necessitates thoracentesis or thoracic drain placement, as POPE is an important cause of postoperative hypoxia, which may result in liver failure [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. POPE can thus prolong hospitalization and increase costs [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Furthermore, occurrence of POPE not only affects short-term outcomes, but can also delay postoperative rehabilitation and subsequent disease treatment. In patients with hepatocellular carcinoma, POPE has been reported as an independent risk factor for recurrence and patient death [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Identification of risk factors for POPE is therefore important.\u003c/p\u003e \u003cp\u003eCardiothoracic ratio (CTR) is a simple value to evaluate heart size from chest radiographs [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. CTR has been found to offer a useful prognostic factor in several diseases. In cardiovascular disease, CTR is used to indicate cardiomegaly and is associated with heart failure [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. A higher CTR is associated with higher mortality among patients on hemodialysis [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Higher CTR also indicates pulmonary venous congestion [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, to best of our knowledge, no association between CTR and POPE after hepatectomy has been reported.\u003c/p\u003e \u003cp\u003eWe investigated risk factors for POPE and examined whether CTR could allow early detection of POPE.\u003c/p\u003e"},{"header":"Material And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003e Participants in this retrospective study comprised 382 consecutive patients who had undergone hepatectomy (including both with/without biliary reconstruction followed by extrahepatic bile duct resection) for malignant or benign disease between January 2012 and December 2021 at Ehime University Hospital. Donors and recipients of liver transplantation as well as patients who had received placement of an intraoperative thoracic drainage tube due to accidental thoracotomy were excluded. Data on background characteristics, perioperative laboratory data, perioperative clinical data, pathological findings, and CTR were collected from medical records. This protocol was reviewed and approved by the institutional ethics committee of Ehime University Hospital in 2022. All participants, including retrospectively registered patients or their guardians, verbally consented to the use of their medical information for scientific research (approval no. EUH2205008).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eOperative Procedures And Perioperative Management\u003c/h3\u003e\n\u003cp\u003eIndications for surgery and surgical procedures were decided by a multidisciplinary team. Mobilization of the liver was performed only when required to resect a tumor safely. Patients essentially underwent intermittent hepatic pedicle occlusion during parenchymal dissection. The liver parenchyma was transected using a Cavitron ultrasonic surgical aspirator (Integra Lifesciences Corporation, Plainsboro, NJ, USA) and electric cautery equipped with channels for water dripping. Vessels that appeared in transected sections were generally ligated. Stumps of hepatic or portal veins were sutured using non-absorbable monofilament suture or divided using a linear stapler. One or two closed suction drainage tubes were usually placed close to the cut surface of the liver Winslow\u0026rsquo;s foramen according to the preference of the operator. Regarding postoperative management, patients with hypoxia or dyspnea for whom PE could be drained safely under computed tomography (CT) or ultrasound (US) guidance was one of the criteria for PE drainage. Asymptomatic hypoxia or assumption of worsened dyspnea with \u0026gt;\u0026thinsp;500 mL of PE on CT or US was another criterion. In-out balance was calculated as the infusion volume minus urine volume minus drain output on postoperative day (POD)1. Albumin was transfused when serum albumin value was \u0026lt;\u0026thinsp;2.5mg/dL in early postoperative phase or to maintain appropriate blood pressure.\u003c/p\u003e \u003cp\u003ePostoperative complications were defined according to the Clavien\u0026ndash;Dindo classification, and events of grade III or above were defined as major complications. POPE of grade III (thoracentesis or thoracic drain placement) or above was defined as clinically relevant POPE (CR-POPE) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eCalculation Of Ctr And Ct Volumetry For Pope\u003c/h3\u003e\n\u003cp\u003eCTR was calculated as the ratio of the maximal horizontal diameter of the heart to the maximal diameter of the thoracic wall on a chest radiograph (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Preoperative chest radiographs were taken in a standing position within 1 month before surgery. Postoperative chest radiographs in a supine position were taken in the operating room immediately postoperatively and in the intensive care unit the next morning.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ePostoperative chest and abdominal CT were taken around 1 week after surgery in most patients. Estimated POPE volume was calculated using 3-dimensional imaging software (SYNPASE VINCENT medical imaging system; Fujifilm Medical, Tokyo, Japan) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Estimated POPE volume was measured before thoracentesis in the CR-POPE group.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eAll statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS\u0026reg;) for Windows\u0026reg; (v.24.0; SPSS, Chicago, IL, USA). Longitudinal trends between CTR and estimated POPE volume were calculated using Spearman ρ correlations. Continuous variables were compared using Mann\u0026ndash;Whitney U tests and are presented as medians with ranges. Optimal cut-offs for CTR and other risk factors were determined using receiver operating characteristic (ROC) curve analysis or standard cut-offs. Categorical variables were compared using χ\u003csup\u003e2\u003c/sup\u003e or Fisher\u0026rsquo;s exact tests and are presented with ratios. Significant variables on univariate analyses were included in multivariate analyses with stepdown logistic regression and likelihood tests. Regression models were calibrated using Hosmer\u0026ndash;Lemeshow tests. Significance was defined at the level of \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv class=\"Section2\" id=\"Sec8\"\u003e\n \u003ch2\u003eUnivariate analysis for CR-POPE\u003c/h2\u003e\n \u003cp\u003eOf the 382 patients who underwent hepatectomy, 38 patients (10.0%) had CR-POPE. Thirty-seven patients had right-sided POPE and one had left-sided POPE. Median time from hepatectomy to drainage of POPE was 6 days (range, 2\u0026ndash;35 days). Median volume of pleural fluid drained on the day of thoracentesis was 732 mL (range, 160\u0026ndash;2,150 mL). Patient characteristics are summarized in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. The CR-POPE group showed higher preoperative total serum bilirubin level. Preoperative CTR, preoperative cardiac function and respiratory function did not differ significantly between groups.\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePreoperative factors\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" style=\"width: 35.592%;\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003eNon-CR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;344\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003eCR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;38\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eSex, male\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e254 (73.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e29 (76.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.741\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eAge, years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e70 (26\u0026ndash;89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e72 (41\u0026ndash;80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.793\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eBody mass index, kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e23.8 (15.4\u0026ndash;39.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e23.8 (17.2\u0026ndash;32.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.740\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eComorbidities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eDiabetes mellitus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e111 (32.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e9 (23.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.295\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eHypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e194 (56.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e23 (60.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.626\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eChronic kidney disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e16 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e3 (7.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.290\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eCardiovascular disease\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e50 (14.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e6 (15.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.836\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003ePrevious hepatectomy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e66 (19.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e3 (8.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.086\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eChemotherapy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e76 (22.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e5 (13.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.201\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eRFA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e44 (12.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e3 (7.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.601\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eTACE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e86 (24.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e6 (15.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.249\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eBlood biochemistry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eHemoglobin, g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e12.9 (7.9\u0026ndash;19.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e12.6 (7.9\u0026ndash;16.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.938\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003ePlatelet, 10\u003csup\u003e4\u003c/sup\u003e/\u0026micro;L\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e18.8 (4.5\u0026ndash;64.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e17.6 (8.0-56.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.567\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eTotal bilirubin, mg/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e0.6 (0.2\u0026ndash;22.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e0.8 (0.3\u0026ndash;10.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eAlbumin, g/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e3.8 (2.5\u0026ndash;5.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e3.8 (2.6\u0026ndash;4.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.606\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eCreatinine, mg/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e0.80 (0.20\u0026ndash;8.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e0.82 (0.41\u0026ndash;6.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.451\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003ePT-INR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e1.00 (0.83\u0026ndash;2.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e1.00 (0.84\u0026ndash;1.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.555\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eICGR15, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e12 (1\u0026ndash;48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e10 (2\u0026ndash;25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.06\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eEchocardiography\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eLVDd, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e45.6 (28.2\u0026ndash;65.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e26.9 (40.4\u0026ndash;56.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.105\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eLVDs, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e28.0 (17.0\u0026ndash;46.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e29.0 (20.0-40.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.203\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eLVEF, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e66.7 (44.2\u0026ndash;83.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e66.2 (43.5\u0026ndash;78.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.707\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eLAD, mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e36.0 (17.2\u0026ndash;51.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e36.1 (25.1\u0026ndash;59.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.980\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eSpirometry\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003e%VC, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e108 (39\u0026ndash;151)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e102 (65\u0026ndash;129)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.062\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003e%FEV\u003csub\u003e1.0\u003c/sub\u003e, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e76 (27\u0026ndash;100)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e76 (54\u0026ndash;81)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.663\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eChild-Pugh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.647\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e320 (93.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e34 (89.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e23 (6.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e4 (10.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e1 (0.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 35.592%;\"\u003e\n \u003cp\u003eCTR, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e47.0 (35.0-60.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 24.3524%;\"\u003e\n \u003cp\u003e48.6 (40.1\u0026ndash;67.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 7.7428%;\"\u003e\n \u003cp\u003e0.065\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\" style=\"width: 92.664%;\"\u003e\n \u003cp\u003eRFA, radiofrequency ablation; TACE, transcatheter arterial chemoembolization; PT-INR, prothrombin time-international normalized ratio; ICGR15: indocyanine green retention rate at 15 min; LVDd, left ventricular diameter at end-diastole; LVDs: left ventricular diameter at end-systole; LVEF: left ventricular ejection fraction; LAD: left atrial dimension; %VC: vital capacity percentage; %FEV1.0: forced expiratory volume in 1 s as a percentage of forced vital capacity; CTR, cardiothoracic ratio; CR-POPE, clinically relevant postoperative pleural effusion.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eIn terms of intraoperative variables, type of abdominal incision, prolonged duration of hepatic pedicle occlusion, higher estimated blood loss, greater frequency of red blood cell transfusion, higher infusion volume, lower urine volume, greater number of resected liver segments, biliary reconstruction, and diaphragm incision were all associated with occurrence of CR-POPE (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eIntraoperative factors\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNon-CR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;344\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;38\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbdominal incision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLaparoscopy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e95 (27.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0 (0.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33 (9.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (2.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReversed L-shape\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e151 (43.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27 (71.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eInverted T-shape\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66 (18.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 (26.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHepatic pedicle occlusion time, min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53 (0-240)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61 (0-274)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.020\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOperation time, min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e388 (87\u0026thinsp;\u0026minus;\u0026thinsp;1,094)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e427 (170\u0026ndash;990)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.372\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEstimated blood loss per BW, g/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.9 (0-61.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21.3 (1.2-109.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRed blood cell transfusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93 (27.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26 (68.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntraoperative infusion volume per BW, mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e63.2 (15.7-163.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e109.2 (54.5-264.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntraoperative urine volume per BW, mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.8 (0-58.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.6 (0-64.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSurgical site on S7 or S8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e154 (44.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20 (52.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.393\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNumber of resected segments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (0\u0026ndash;6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 (0\u0026ndash;6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBiliary reconstruction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33 (9.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (36.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiaphragm incision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (4.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 (13.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.031\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eBW, body weight; CR-POPE, clinically relevant postoperative pleural effusion.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eRegarding postoperative variables, the CR-POPE group showed a higher CTR on both POD0 and POD1, higher infusion volume on POD1, higher urine volume on POD1, prolonged duration of hospitalization and a greater frequency of major postoperative complications excluding POPE (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePostoperative factors\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" style=\"width: 42.8219%;\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003eNon-CR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;344\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003eCR-POPE\u003c/p\u003e\n \u003cp\u003e\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;38\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eHospital stays, days\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e13 (3-163)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e40 (7-164)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eMajor postoperative complications excluding POPE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e43 (12.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e25 (65.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eBile leakage\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e18 (5.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e7 (18.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eIntra-abdominal hemorrhage\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e3 (0.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e3 (7.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eIntra-abdominal infection\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e10 (2.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e8 (21.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003ePortal vein thrombosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e2 (5.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.010\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eLiver failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e2 (0.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e4 (10.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eCTR on POD0, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e54.9 (41.6\u0026ndash;67.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e56.4 (45.4\u0026ndash;65.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.045\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eCTR on POD1, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e55.5 (42.7\u0026ndash;66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e59.3 (49.4\u0026ndash;67.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eInfusion volume on POD1 per BW, mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e38.5 (8.5\u0026ndash;95.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e49.0 (18.7\u0026ndash;74.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eUrine volume on POD1 per BW, mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e25.6 (0-102.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e17.3 (0-52.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eIn-out balance on POD1 per BW, mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e9.3 (-62.1-60.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e20.2 (14.1\u0026ndash;50.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003ePathological findings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eHepatocellur carcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e174 (50.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e14 (36.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eCholangiocarcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e48 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e14 (36.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eMetastatic tumor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e106 (30.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e8 (21.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eOther\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e16 (4.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e2 (5.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 42.8219%;\"\u003e\n \u003cp\u003eCirrhosis of resected liver, F4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e60 (17.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 14.0223%;\"\u003e\n \u003cp\u003e8 (21.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6876%;\"\u003e\n \u003cp\u003e0.581\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\" style=\"width: 78.3091%;\"\u003e\n \u003cp\u003eCirrhosis was pathologically diagnosed according to the Inuyama classification.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"4\" style=\"width: 78.3091%;\"\u003e\n \u003cp\u003eCTR, cardiothoracic ratio; POD, postoperative day; CR-POPE, clinically relevant postoperative pleural effusion.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eCorrelation Between Ctr On Pod1 And Estimated Pope Volume\u003c/h3\u003e\n\u003cp\u003eEstimated POPE volume was evaluated from CT images among 250 patients at a median of 7 postoperative days (range, 1\u0026ndash;16 days). Figure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows scatter plots of CTR on POD1 and estimated POPE volume. Estimated POPE volume correlated with CTR on POD1 (r\u0026thinsp;=\u0026thinsp;0.175; 95% confidence interval [CI], 0.055\u0026ndash;0.290; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.005).\u003c/p\u003e\n\u003ch3\u003eCalculation Of Optimal Ctr Cut-off\u003c/h3\u003e\n\u003cp\u003eThe optimal cut-off was determined using ROC curve analysis (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). Area under the ROC curve for CTR on POD1 was 0.678 (95%CI, 0.580\u0026ndash;0.775) and the most appropriate cut-off was determined to be 59.0. This value offered 57.9% sensitivity and 80.5% specificity.\u003c/p\u003e\n\u003ch2\u003eMultivariate Analysis For Cr-pope\u003c/h2\u003e\n\u003cp\u003eFactors that showed significant correlations with CR-POPE on univariate analyses were entered into the multivariate analysis (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). On multivariate analysis, abdominal incision with a reversed L-shape or inverted T-shape (odds ratio [OR], 3.07; 95%CI, 1.17\u0026ndash;8.04; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.023), estimated blood loss\u0026thinsp;\u0026gt;\u0026thinsp;772 g (OR, 2.71; 95%CI, 1.01\u0026ndash;7.28; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.049), diaphragm incision (OR, 8.31; 95%CI, 1.75\u0026ndash;39.45; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008), major postoperative complications excluding POPE (OR, 7.99; 95%CI, 3.13\u0026ndash;20.41; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), intraoperative infusion volume per body weight (BW)\u0026thinsp;\u0026gt;\u0026thinsp;80 mL/kg (OR, 4.8; 95%CI, 1.55\u0026ndash;14.86; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007) and CTR on POD1\u0026thinsp;\u0026gt;\u0026thinsp;59.0% (OR, 4.34; 95%CI, 1.77\u0026ndash;10.66; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001) were identified as independent risk factors for CR-POPE (Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab4\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eUni- and multivariate analyses to identify predictors of clinically relevant postoperative pleural effusion\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" style=\"width: 43.7372%;\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003eUnivariate\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 6.6557%;\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003eMultivariate\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" style=\"width: 6.7613%;\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003eOdds ratio\u003c/p\u003e\n \u003cp\u003e(95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003eOdds ratio\u003c/p\u003e\n \u003cp\u003e(95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eTotal bilirubin\u0026thinsp;\u0026lt;\u0026thinsp;0.9 mg/dL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e2.60\u003c/p\u003e\n \u003cp\u003e(1.28\u0026ndash;5.31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003cp\u003e(0.09\u0026ndash;3.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.560\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eAbdominal incision\u003c/p\u003e\n \u003cp\u003e(reversed L-shape or inverted T-shape)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e3.48\u003c/p\u003e\n \u003cp\u003e(1.63\u0026ndash;7.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e3.07\u003c/p\u003e\n \u003cp\u003e(1.17\u0026ndash;8.04)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.023\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eHepatic pedicle occlusion time\u0026thinsp;\u0026gt;\u0026thinsp;33 min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e1.95\u003c/p\u003e\n \u003cp\u003e(0.95\u0026ndash;3.99)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.067\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eEstimated blood loss\u0026thinsp;\u0026gt;\u0026thinsp;772 g\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e9.37\u003c/p\u003e\n \u003cp\u003e(4.27\u0026ndash;20.58)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e2.71\u003c/p\u003e\n \u003cp\u003e(1.01\u0026ndash;7.28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.049\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eRed blood cell transfusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e5.82\u003c/p\u003e\n \u003cp\u003e(2.82\u0026ndash;12.02)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e1.74\u003c/p\u003e\n \u003cp\u003e(0.66\u0026ndash;4.60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.266\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eResected Segments\u0026thinsp;\u0026gt;\u0026thinsp;3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e3.23\u003c/p\u003e\n \u003cp\u003e(1.63\u0026ndash;6.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e0.77\u003c/p\u003e\n \u003cp\u003e(0.22\u0026ndash;2.73)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.684\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eBiliary reconstruction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e5.50\u003c/p\u003e\n \u003cp\u003e(2.60\u0026ndash;11.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003cp\u003e(0.09\u0026ndash;3.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.560\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eDiaphragm incision\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e3.57\u003c/p\u003e\n \u003cp\u003e(1.21\u0026ndash;10.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e8.31\u003c/p\u003e\n \u003cp\u003e(1.75\u0026ndash;39.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eMajor postoperative complications excluding POPE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e13.46\u003c/p\u003e\n \u003cp\u003e(6.41\u0026ndash;28.28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e7.99\u003c/p\u003e\n \u003cp\u003e(3.13\u0026ndash;20.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eIntraoperatieve infusion volume per BW\u0026thinsp;\u0026gt;\u0026thinsp;80 mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e11.44\u003c/p\u003e\n \u003cp\u003e(4.87\u0026ndash;26.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e4.80\u003c/p\u003e\n \u003cp\u003e(1.55\u0026ndash;14.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eIn-out balance on POD1 per BW\u0026thinsp;\u0026gt;\u0026thinsp;20 mL/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e3.79\u003c/p\u003e\n \u003cp\u003e(1.91\u0026ndash;7.52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e2.20\u003c/p\u003e\n \u003cp\u003e(0.91\u0026ndash;5.31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.081\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003ePathological findings, cholangiocarcinoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e3.60\u003c/p\u003e\n \u003cp\u003e(1.74\u0026ndash;7.44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e1.19\u003c/p\u003e\n \u003cp\u003e(0.43\u0026ndash;3.28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.739\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" style=\"width: 43.7372%;\"\u003e\n \u003cp\u003eCTR on POD1\u0026thinsp;\u0026gt;\u0026thinsp;59.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.0928%;\"\u003e\n \u003cp\u003e5.40\u003c/p\u003e\n \u003cp\u003e(2.70-10.83)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.6557%;\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 11.5154%;\"\u003e\n \u003cp\u003e4.34\u003c/p\u003e\n \u003cp\u003e(1.77\u0026ndash;10.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" style=\"width: 6.7613%;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"5\" style=\"width: 80.7131%;\"\u003e\n \u003cp\u003ePOPE, postoperative pleural effusion; BW, body weight; CTR, cardiothoracic ratio; POD, postoperative day; CI, confidence interval.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003ePOPE is one of the most common postoperative complications after liver resection. Previous studies have reported various risk factors for POPE, including age, body mass index, chronic obstructive pulmonary disease, resection site of liver, resected liver weight, operative time, and transfusion [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The present study revealed abdominal incision, blood loss, diaphragm incision, and intraoperative infusion volume as independent risk factors for CR-POPE. CTR on POD1 was identified as an independent predictor. Moreover, estimated POPE volume using CT volumetry correlated with CTR on POD1. CT volumetry for POPE is a novel approach that allows continuous quantification of volume.\u003c/p\u003e \u003cp\u003eGenerally, PE is classified as exudative (due to imbalances in hydrostatic or oncotic pressures) or transudative (inflammatory) effusion based on the pathophysiology [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. POPE following coronary artery bypass surgery is classified as exudative, but POPE following hepatobiliary surgery is uncertain. PE after liver resection might have a dual etiology of both hypoalbuminemia with cirrhosis and direct inflammatory responses to the thoracic cavity. Clinically, most POPE tends to arise in the right-sided pleural cavity. Risk factors including abdominal incision, resection site, incision in the diaphragm to reach the liver, and tumor invasion to the diaphragm, indicated the influence of local inflammation. Another strongly associated factor, was postoperative complications excluding POPE, such as bile leakage or cut-end abscess, which demonstrate local or systemic inflammation, leading to secondary POPE. However, since biochemical data for PE were lacking, it remains unclear whether POPE is a result of other complications or a sign of complications, or both.\u003c/p\u003e \u003cp\u003ePostoperative hypoalbuminemia is also reportedly associated with POPE [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. We therefore investigated the impact of hemodynamics on CR-POPE and whether CTR could predict CR-POPE. Excessive infusion volume has been reported to worsen postoperative pulmonary function [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Surgical invasion has direct effects on fluid retention. Plasma volume decreases with general anesthesia alone [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Under such conditions of intraoperative hemodynamics, fluid distributes into the interstitium. A Danish multicenter randomized trial showed that a higher volume of intraoperative fluid infusion resulted in sodium retention and weight gain for 2\u0026ndash;3 days after surgery, then declined [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. This accumulation of fluid and delayed clearance may cause excessive intravascular volume loading, leading to pulmonary edema and PE. Postoperative enlargement of the CTR is a sign of overloading and cardiomegaly. In the present study, the CR-POPE group showed a significantly higher infusion volume and lower urine volume intraoperatively. Furthermore, infusion volume correlated with both estimated POPE volume and CTR. This demonstrated that an excessive fluid balance resulted in POPE. Perioperative fluid management should be administered appropriately according to blood loss [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, if the operation takes a longer time, total infusion volume will be correspondingly higher. In hepatobiliary surgery, bleeding from the liver parenchyma sometimes requires massive infusion or transfusion. Attention must be paid to the infusion volume, particularly in patients with poor cardiac, respiratory, or renal function or the elderly.\u003c/p\u003e \u003cp\u003eAdjusting postoperative infusion volume and early administration of diuretics could inhibit excessive overloading. On the other hand, goal-directed fluid therapy that requires perioperative fluid restriction has become widespread, and is being trialed for liver resection [\u003cspan additionalcitationids=\"CR22\" citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Transition of surgery and anesthesia might affect the occurrence of postoperative complications. Actually, the present cohort showed a lower incidence of CR-POPE than previous reports [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the present study, abdominal incision was an independent factor. Recent progress in minimally invasive surgery has led to increases in laparoscopic surgery [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Conversely, the occurrence of comorbidities has decreased in laparoscopic surgery [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The higher estimated blood loss, transfusion and biliary reconstruction in the CR-POPE group may support secondary POPE due to other postoperative complications. In fact, postoperative complications were independently associated with CR-POPE.\u003c/p\u003e \u003cp\u003eThe CTR is a well-established value in the clinical setting for evaluating cardiac morphology radiologically [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Rayner et al. reported that CTR on cardiac radiographs correlated with left ventricular mass on echocardiography [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Previous studies have reported the prognostic utility of the CTR. A larger CTR could be a predictive marker of sudden death in patients with chronic heart failure and long-term survival rate in patients with hemodialysis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Those studies demonstrated that hemodynamics had an effect on CTR. Further, a larger CTR is a prognostic factor for short-term postoperative outcomes in cardiac surgery [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. However, no investigations with non-cardiac surgery have been conducted and this is the first to show an impact of CTR on postoperative outcomes.\u003c/p\u003e \u003cp\u003eThis retrospective study showed several limitations. Imaging conditions for chest radiography might vary depending on the status of the patient. Postoperative abdominal pain alters respiratory functions. Patients with chronic obstructive pulmonary disease often have a smaller CTR, whereas patients with chronic heart failure have a larger CTR. The advantage of CTR measurement is that this simple method can be applied using chest radiographs. Several advanced imaging modalities have emerged recently, such as CT, magnetic resonance imaging, and radioisotope imaging [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. However, radiographs cannot replace these options because of the convenience, speed, and low exposure. Radiographs can be taken anywhere using mobile equipment without patient transfer. Although the rate of increase in CTR from pre- to postoperatively is also useful, here we offer a use for postoperative CTR on POD1 with clinical utility. In the present study, the properties of PE using pleural fluid were not examined and further investigations should be conducted in the future.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe present study revealed CTR\u0026thinsp;\u0026gt;\u0026thinsp;59.0% is one of the risk factors of CR-POPE following hepatectomy. Larger CTR may facilitate appropriate postoperative management.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions:\u003c/strong\u003e AS and KS contributed to the study conception and design. NF, MS, MU, TN, TU, KT, KS, KO, and YT performed surgeries and collected data. AS and KS wrote the first draft of the article. KO and YT contributed to the review and critical revision of the article. All authors have approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e The authors declare no conflicts of interest regarding the publication of this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e No funding was received.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eORCID\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAS, 0000-0001-8042-1486, KS, 0000-0002-6431-0011, MU, 0000-0001-7517-5612, TN, 0000-0002-7635-9995, MH, 0000-0001-9642-4155, KT, 0000-0002-6077-5428, NF, 0000-0001-6076-6516, KO, 0000-0002-5672-6308, YT, 0000-0001-9743-1840\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eNitta H, Mitsuura C, Shiraishi Y, et al (2020) Predictive model for postoperative pleural effusion after hepatectomy. Ann Gastroenterol Surg 5:373-380 https://doi.org/10.1002/ags3.12417\u003c/li\u003e\n\u003cli\u003eNobili C, Marzano E, Oussoultzoglou E, et al (2012) Multivariate analysis of risk factors for pulmonary complications after hepatic resection. Ann Surg 255:540-550 https://doi.org/10.1097/SLA.0b013e3182485857\u003c/li\u003e\n\u003cli\u003eUchiyama H, Harimoto N, Itoh S, Yoshizumi T, Ikegami T, Maehara Y. Pleural Effusion After Hepatectomy for Hepatocellular Carcinoma: Risk Factor Analyses and Its Impact on Oncological Outcomes. World J Surg 41:1089-1099 https://doi.org/10.1007/s00268-016-3826-1\u003c/li\u003e\n\u003cli\u003eJiang L, Chen WG, Geng QS, et al (2019) The cardiothoracic ratio: a neglected preoperative risk-stratified method for patients with rheumatic heart disease undergoing valve replacement surgery. Eur J Cardiothorac Surg 55:511-517 https://doi.org/10.1093/ejcts/ezy255\u003c/li\u003e\n\u003cli\u003eKearney MT, Fox KA, Lee AJ, et al (2004) Predicting sudden death in patients with mild to moderate chronic heart failure. Heart 90:1137-1143 https://doi.org/10.1136/hrt.2003.021733 \u003c/li\u003e\n\u003cli\u003eDimopoulos K, Giannakoulas G, Bendayan I, et al (2013) Cardiothoracic ratio from postero-anterior chest radiographs: a simple, reproducible and independent marker of disease severity and outcome in adults with congenital heart disease. Int J Cardiol 166:453-457 https://doi.org/10.1016/j.ijcard.2011.10.125\u003c/li\u003e\n\u003cli\u003eYotsueda R, Taniguchi M, Tanaka S, et al (2017) Cardiothoracic Ratio and All-Cause Mortality and Cardiovascular Disease Events in Hemodialysis Patients: The Q-Cohort Study. 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Dig Surg 36:514-521 https://doi.org/10.1159/000494218 \u003c/li\u003e\n\u003cli\u003eShimizu Y, Sano T, Yasui K (2007) Predicting pleural effusion and ascites following extended hepatectomy in the non-cirrhotic liver. J Gastroenterol Hepatol 22:837-840 https://doi.org/10.1111/j.1440-1746.2007.04872.x.\u003c/li\u003e\n\u003cli\u003eLight RW (2002) Clinical practice. Pleural effusion. N Engl J Med 346:1971-1977 https://doi.org/10.1056/NEJMcp010731.\u003c/li\u003e\n\u003cli\u003eSahn SA (1982) The differential diagnosis of pleural effusions. West J Med 137:99-108\u003c/li\u003e\n\u003cli\u003eJeong HW, Kim JW, Shin WJ, et al (2019) Early postoperative hypoalbuminaemia is associated with pleural effusion after donor hepatectomy: A propensity score analysis of 2316 donors. Sci Rep 9:2790 https://doi.org/10.1038/s41598-019-39126-0\u003c/li\u003e\n\u003cli\u003eLowell JA, Schifferdecker C, Driscoll DF, Benotti PN, Bistrian BR (1990) Postoperative fluid overload: not a benign problem. Crit Care Med 18:728-733 https://doi.org/10.1097/00003246-199007000-00010\u003c/li\u003e\n\u003cli\u003eNational Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network, Wiedemann HP, et al (2006) Comparison of two fluid-management strategies in acute lung injury. N Engl J Med 354:2564-2575 https://doi.org/10.1056/NEJMoa062200\u003c/li\u003e\n\u003cli\u003eNorberg A, Hahn RG, Li H, et al (2007) Population volume kinetics predicts retention of 0.9% saline infused in awake and isoflurane-anesthetized volunteers. Anesthesiology 107:24-32 https://doi.org/10.1097/01.anes.0000268387.34758.6d.\u003c/li\u003e\n\u003cli\u003eBrandstrup B, T\u0026oslash;nnesen H, Beier-Holgersen R, et al (2003) Effects of intravenous fluid restriction on postoperative complications: comparison of two perioperative fluid regimens: a randomized assessor-blinded multicenter trial. 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Eur J Cardiothorac Surg 55:511-517 https://doi.org/10.1093/ejcts/ezy255 \u003c/li\u003e\n\u003cli\u003eMcAdams HP, Samei E, Dobbins J 3rd, Tourassi GD, Ravin CE (2006) Recent advances in chest radiography. Radiology 241:663-683 https://doi.org/10.1148/radiol.2413051535\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"cardiothoracic ratio, hepatectomy, pleural effusion, postoperative complication","lastPublishedDoi":"10.21203/rs.3.rs-2807394/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2807394/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003ePurpose\u003c/b\u003e\u003c/p\u003e \u003cp\u003eAlthough several preoperative risk factors for postoperative pleural effusion (POPE) after hepatectomy have been reported, few postoperative predictors have been investigated. We aimed to examine risk factors for clinically relevant POPE (CR-POPE) and whether cardiothoracic ratio (CTR) could be a predictive factor.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eParticipants in this retrospective investigation comprised 382 patients who underwent hepatectomy between January 2012 and December 2021. Perioperative characteristics that were considered potential risk factors for CR-POPE were evaluated. CR-POPE was defined as having undergone thoracentesis or thoracic drain placement.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003ePatients were divided into a CR-POPE group (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;38; 10.0%) and a non-CR-POPE group (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;344; 90.0%). The CR-POPE group showed significantly higher intraoperative infusion volume (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and lower intraoperative urine volume (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.015). In multivariate analysis, abdominal incision with a reversed L-shape or inverted T-shape (odds ratio [OR]\u0026thinsp;=\u0026thinsp;3.07, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.023], estimated blood loss\u0026thinsp;\u0026gt;\u0026thinsp;772 g (OR\u0026thinsp;=\u0026thinsp;2.71, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.049), diaphragm incision (OR\u0026thinsp;=\u0026thinsp;8.31, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.008), major postoperative complications excluding CR-POPE (OR\u0026thinsp;=\u0026thinsp;7.99, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), intraoperative infusion volume per body weight\u0026thinsp;\u0026gt;\u0026thinsp;80 mL/kg (OR\u0026thinsp;=\u0026thinsp;4.80, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.007) and CTR on postoperative day (POD)1\u0026thinsp;\u0026gt;\u0026thinsp;59.0% (OR\u0026thinsp;=\u0026thinsp;4.34, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001) were all independently associated with occurrence of POPE.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eWe clarified risk factors for CR-POPE following hepatectomy. The occurrence of CR-POPE might be predictable from the CTR on POD1.\u003c/p\u003e","manuscriptTitle":"Postoperative cardiothoracic ratio on the first postoperative day is a predictor of postoperative pleural effusion drainage following hepatectomy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-04-17 14:46:17","doi":"10.21203/rs.3.rs-2807394/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a37d9fa7-b2ae-49a9-be74-328ee736b22a","owner":[],"postedDate":"April 17th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-06-12T10:44:32+00:00","versionOfRecord":[],"versionCreatedAt":"2023-04-17 14:46:17","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2807394","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2807394","identity":"rs-2807394","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}