Surgical Bleeding in Patients Undergoing Posterior Lumbar Inter body Fusion Surgery: A Randomized Clinical Trial Evaluating the Effect of Two Mechanical Ventilation Mode Types

Surgical Bleeding in Patients Undergoing Posterior Lumbar Inter body Fusion Surgery: A Randomized Clinical Trial Evaluating the Effect of Two Mechanical Ventilation Mode Types | 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 Surgical Bleeding in Patients Undergoing Posterior Lumbar Inter body Fusion Surgery: A Randomized Clinical Trial Evaluating the Effect of Two Mechanical Ventilation Mode Types Mohammad Hajijafari, Mohammad Hossein Ziloochi, Manoochehr Salimian, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2016748/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 12 Mar, 2023 Read the published version in European Journal of Medical Research → Version 1 posted 8 You are reading this latest preprint version Abstract Background The purpose of the study was to compare the effect of using Volume-Controlled Ventilation (VCV) versus Pressure-Controlled Ventilation (PCV) on blood loss in patients undergoing Posterior Lumbar Inter body Fusion (PLIF) surgery. Methods In a randomized, single-blinded, parallel design, 78 patients candidate for PLIF surgery were randomly allocated into two groups of 39 to mechanically ventilated using VCV or PCV mode. All the patients were operated in prone position by one surgeon. Amount of intraoperative surgical bleeding, transfusion requirement, surgeon satisfaction, hemodynamic parameters, heart rate, and blood pressure were measured as outcomes. Results PCV group showed slightly better outcomes than VCV group in terms of mean blood loss (431 cc vs. 465 cc), transfusion requirement (0.40 vs. 0.43 unit), and surgeon satisfaction (82.1% vs. 74.4%); however, the differences were not statistically significant. Diastolic blood pressure 90 and 105 min. after induction were significantly lower in PCV group (P = 0.043 & 0.019 respectively); however, blood pressure in other times, hemoglobin levels, and mean heart rate were similar in two groups. Conclusions In patients undergoing Posterior Lumbar Inter body Fusion surgery, mode of ventilation cannot make significant difference in terms of blood loss; however, some minor benefits in outcomes may lead to the selection of PCV rather than VCV. More studies with larger sample size, and investigating more factors may be needed. Pressure-Controlled Ventilation Volume-Controlled Ventilation Posterior Lumbar Inter body Fusion Surgical Blood Loss Figures Figure 1 Introduction Demand for lumbar spine fusion, a common surgical procedure used for the treatment of many spinal conditions, has been increased in recent decades ( 1 ). Although several surgical approaches exist for the interbody fusion, Posterior Lumbar Interbody Fusion (PLIF) is generally used due to its effective access and desirability of the surgical field ( 2 ). PLIF surgery may improve physical activity and satisfaction of patients with chronic back pain ( 3 ). However; surgical bleeding as a main concern in spine surgery has put lumbar spine fusion among the top 10 surgical procedures that necessitate blood transfusion ( 1 , 4 – 9 ). Reduction of surgical blood loss is crucial to maintain hemodynamic stability and the desirability of the surgical field. Meanwhile, convenience of the surgeon is associated with reduction of intraoperative blood loss due to reduced operation time ( 10 ). Many factors contribute to the amount of intraoperative blood loss including sex, body mass index (BMI), the severity of deformity, surgical approach, number of levels, and anesthetic factors, such as the mode of mechanical ventilation ( 7 , 11 , 12 ). Volume-controlled ventilation (VCV), which is known as the classic ventilation mode, has been used for decades with a constant flow to deliver a target tidal volume and thus ensure satisfactory minute ventilation; however, using VCV mode may result in high airway pressure levels when chest compliance decreased, such as in obese patients, and lead to ventilation induced lung injury ( 13 , 14 ). Limited inspiratory pressure in pressure-controlled ventilation (PCV), an alternative mode of mechanical ventilation, may reduce the risk of barotrauma and volutrauma. It also ensures that collapsed alveoli open up by extending the inspiratory time using sufficient positive end expiratory pressure (PEEP) levels ( 15 ). Although there is no remarkable differences between the two ventilation modes, some researchers have carefully recommended changing the ventilation settings from VCV to PCV in some situations ( 16 , 17 ). Regarding to bleeding outcome, some studies have particularly shown that using PCV can reduce intraoperative blood loss ( 13 , 18 – 21 ); however, there are some controversies in this regard ( 22 , 23 ). Considering the above-mentioned controversies, we carried out the present study to investigate the effect of mechanical ventilation mode on the outcomes in patients undergoing posterior lumbar inter body fusion (PLIF) in prone position. To reach this goal we compared VCV and PCV in terms of surgical outcomes. Our primary outcome was the amount of intraoperative blood loss. Secondary outcomes were heart rate, blood pressure, transfusion requirement, and surgeon satisfaction. Methods Study Design and Population This prospective, randomized, parallel and one-way blinded clinical trial, was conducted at Shahid Beheshti Hospital, a teaching hospital affiliated by Kashan University of Medical Sciences (KAUMS), Kashan, Iran; between 2017 and 2019. To recruit the participants, 100 patients with ASA class 1 and 2, aged between 18 and 75 years old, who were candidates for PLIF, were assessed. Among them, 22 patients were excluded. Exclusion criteria were: respiratory diseases like asthma and COPD (N = 3), heart diseases such as heart failure, myocardial infarction, and valvar diseases (N = 2), Coagulation diseases or anticoagulant consumption (N = 5), BMI > 30 (N = 8), and history of any previous lumbar or chest surgery (N = 4). After obtaining the written informed consent, the remained patients were randomly allocated into two groups of 39, namely VCV and PCV group (Fig. 1 ). The permuted block randomization was used for the participants’ allocation (allocation ratio = 1:1). To do this, a computer-generated list and sealed envelopes were used. All the patients were operated in prone position by one surgeon and a single surgical team using the same method. Although the surgeon and involved nurses were aware of the study, they were blinded to the details of the study’s protocol. Ethics This study was done from 2017 to 2019 at Shahid Beheshti Hospital, a teaching hospital affiliated by Kashan University of Medical Sciences (KAUMS). The study protocol was approved by the Ethics committee of KAUMS (Ethical code IR.KAUMS.REC.1395.50) All methods were carried out in accordance with relevant guidelines and regulations and with CONSORT recommendations. Anesthetic protocol Attending anesthesiologist managed the anesthesia process. After establishing routine patient monitoring (heart rate, noninvasive blood pressure, pulse oximetry, and end tidal CO2), anesthesia was induced with an intravenous premedication of 2µg/kg fentanyl, 0.03 mg/kg midazolam, 5 mg/kg sodium thiopental, and 0.5 mg/kg atracurium. Endotracheal tube with a suitable size, a high-volume, and a low-pressure cuff was inserted for the patients. Invasive monitoring of blood pressure through radial artery were applied for all patients after induction. Anesthesia was maintained with infusion of propofol 100–200 µg /Kg/min as well as 30/70% of O2/N2O mixture to maintain MAP around 70 mmHg. Intervention In PCV group, mechanical ventilation begun with PIP = 15 mmHg, RR = 12/min, I/E= ½, and PEEP = 3. Then the PIP was adjusted to achieve a tidal volume that was calculated as the ideal body weight (50 [female: 45.5] + 0.91 [height − 152.4]) × 7 ml. In addition, the respiratory rate was controlled, using the end-tidal carbon dioxide pressure (ETco2) ranged from 35 to 40 mmHg. In VCV group, TV was set as 7 ml/IBW; however, RR, I/E, and PEEP were chosen as PCV group. Afterward, anesthesia was reversed with 0.04 mg/Kg neostigmine and 0.02 mg /Kg atropine. Outcome measures Amount of intraoperative surgical bleeding, transfusion requirement, surgeon satisfaction, hemodynamic parameters, heart rate, blood pressure, and duration of surgery were measured. The amount of bleeding was calculated and registered based on the number of completely impregnated gauze pieces (15 cc for each 4 x 4 cm, and 50 cc for each 30 x 30 cm gauze piece), and the amount of blood in the suction bottle. Desirability of surgical field was recorded by the surgeon as good, moderate, or weak. Hemodynamic variables were recorded before the induction, after the intubation, after changing to prone position, every 15 minutes during the operation, at the end of surgery, after extubation, and before leaving the recovery unit. The surgeon and the staff who measured and recorded the hemodynamic variables were blinded to the mode of ventilation. Statistical analysis The findings were analyzed using Kolmogorov-Smirnov test, t-test, Fisher’s exact test, and Chi-square test. SPSS-16 software was used to analyze data. Results During the study, 39 patients in each group of VCV and PCV were analyzed. The variables of sex, age, height, weight, and body mass index (BMI) were not significantly different between VCV and PCV groups; hence, two groups were comparable and similar in terms of demographic and anthropometric profiles (Table 1 ). Table 1 Demographic and anthropometric profiles VCV group (n = 39) PCV group (n = 39) p-value Male 15(38.5%) 16(41%) 0.82 Female 24(61.5%) 23(59%) Age (year) 42.41 ± 10.45 43.77 ± 11.38 0.53 Height(meter) 1.65 ± .9 1.66 ± .1 0.54 Weight(kg) 76.11 ± 11.47 78.77 ± 19.71 0.13 BMI 27.92 ± 4.89 28.42 ± 7.10 0.93 * Independent T test Two groups were also similar with respect to the number of surgical procedure level (Table 2 ). Table 2 number of surgical procedure level in studied groups Group Number of levels Sum P* 2 3 4 5 6 0.068 VCV 0 0% 21 53.8% 11 28.2% 7 17.9% 0 0% 39 100% PCV 1 2.5% 28 70%% 3 7.5% 7 17.5% 1 2.5% 39 100% Sum 1 1.3% 49 17.7% 14 17.7% 14 62% 1 1.3% 39 100% * Fisher’s Exact test Table 3 shows the amount of intraoperative surgical bleeding in the studied groups. Although PCV was associated with less bleeding (431.28 cc vs. 465.26 cc), the difference between two groups was not statistically significant (p = 0.67) (Table 2 ). Table 3 Mean blood loss in the studied groups Group Mean SD P value* VCV 465.26 33.81 0.67 PCV 431.28 36.10 * Independent T test Ten patients in VCV group and 9 cases in PCV group required transfusion of one or two units of packed-cell. The average transfusion requirement in VCV and PCV groups were 0.43 and 0.40 unit respectively; however, there was no significant difference between two groups (p = 1) (Table 4). Table 4 packed-cell units received by patients Group 0 1 2 Sum P value VCV 29(74.4%) 3(7.7%) 7(17.9%) 39(100%) 1 * PCV 30(75%) 3(10%) 6(15%) 39(100%) Sum 59(74.7%) 6(8.9%) 13(16.5%) 78(100%) * Fisher’s Exact test In terms of surgical field desirability, the surgeon evaluated 82.1% of PCV and 74.4% of VCV cases as “Good”; however, the difference between two groups was not significant (p = 0.58) (Table 5). Table 5 surgeon satisfaction Surgeon satisfaction VCV Group PCV Group Sum Good 29(74.36%) 32(82.1%) 61(78.2%) Moderate 9(23.8%) 7(17.9%) 16(20.5%) weak 1(2.56%) 0 1(1.3%) Sum 39(100%) 39(100%) 78(100%) P Value 0/58 * The patients who needed antihypertensive agents during the surgery were just two cases in PCV group. Although this number in VCV group was twice, the statistical test didn’t indicate a significant difference between two groups (p = 0.22) (Table 6 ). Table 6 need for antihypertensive drugs during the surgery Group Need for Blood pressure-lowering drugs No Need for Blood pressure-lowering drugs Sum VCV 4(10.3%) 35(89.7%) 39 (100%) PCV 2(5.1%) 37(94.9%) 39 (100%) Sum 6(7.7%) 72(92.3%) 78 (100%) P Value 0/22 * * Chi Square Like before surgery, measurement of mean hemoglobin in patients of two groups after the surgery showed no significant difference between two groups. (Table 7 ). Table 7 Mean hemoglobin of patients before and after surgery in the study groups Time Group Mean SD P value * Before surgery VCV 13.39 1.47 0.772 PCV 13.48 1.41 After surgery VCV 11.92 1.43 0.775 PCV 12.01 1.41 * Independent T test Diastolic blood pressure 90 and 105 min. after induction were significantly lower in PCV group (P = 0.043 & 0.019 respectively); however, there were no significant difference between blood pressure in other times (Table 8 ). Mean heart rate were also similar in two groups. Table 8 Diastolic blood pressure in studied groups throughout operative time Time VCV Group PCV Group Mean SD Mean SD P Value Before Induction 87.03 13.61 83.62 11.63 0.238 After Induction 74.23 14.16 71.44 12.64 0.361 After change of position (from supine to prone) 77.49 16.57 79.13 16.16 0.659 15 min. 72.26 14.30 72.00 15.28 0.939 30 min. 67.67 13.51 65.69 12.94 0.512 45 min. 65.74 13.45 60.74 12.61 0.094 60 min. 64.97 13.60 59.46 10.56 0.049 75 min. 65.74 13.24 60.90 9.43 0.066 90 min. 66.79 13.03 61.41 9.83 0.043 105 min. 67.38 11.59 61.59 9.61 0.019 120 min. 66.05 13.57 61.33 9.05 0.075 End of Surgery 71.31 12.83 65.82 11.36 0.049 After repositioning (from prone to supine) 73.74 12.77 70.10 10.16 0.168 Extubation Time 72.00 16.72 72.28 8.36 0.925 Recovery 74.87 10.78 72.03 8.42 0.198 Discussion This study was done to investigate the effect of mechanical ventilation mode on the outcomes in patients undergoing PLIF in prone position. As main outcomes, amount of intraoperative surgical bleeding, transfusion requirement, and surgeon satisfaction were compared in two groups of VCV and PCV. Hemodynamic parameters, heart rate, and blood pressure were also measured and compared in the two groups as other outcomes. PCV group showed slightly better outcomes than VCV group in terms of mean blood loss (431 cc vs. 465 cc), transfusion requirement (0.40 vs. 0.43 unit), and satisfaction of the surgeon from surgical field (82.1% vs. 74.4%); however, the differences were not statistically significant. Zhendan Peng et al after a similar randomized controlled trial reported a similar result of less, but not significant blood loss in PCV group (13). Also, Lauren K. Dunn et al. in a retrospective study on a large sample size found that neither mode of mechanical ventilation nor airway pressure was associated with surgical bleeding or transfusion requirements (22). However, there are some studies in which PCV has been reported to be significantly associated with lesser intraoperative blood loss (18–20, 23). Reduced intraoperative blood loss has been argued to be related to decreased intrathoracic pressure and improved venous drainage which may be in turn due to decreased peak inspiratory pressure (PIP) during PCV (20, 21, 24). To explain the inconsistency of our results with studies that demonstrated significant lesser surgical bleeding during PCV, other factors influencing intraoperative blood loss should be considered. For example, age is an important factor that affects cardiovascular and coagulation status. The mean age of patients in our study was 42–44 years, while the patients in Kang et al study aged more than 64 years old in average. Moreover, all patients in our study were operated in prone position, whereas in some studies the patient’s position during the surgery had been different. Length of surgery and number of surgical levels are among other factors that were different in our study and can explain our different results about surgical blood loss. In our study, diastolic blood pressures 90 and 105 min. after induction were significantly lower in PCV group (P = 0.043 & 0.019 respectively); however, blood pressure in other times, hemoglobin levels, and mean heart rate were similar in two groups. Jun Han et al in a recently published systematic review and meta-analysis have presented that hemodynamics variables are not significantly related to mode of ventilation during spine surgery in prone position (23). Some authors believe that because of hemodynamic stability and providing lower PIP, PCV is a better choice than VCV for patients undergoing lumbar spine fusion surgery (13, 20, 25, 26). In conclusion, this study suggests that mode of ventilation cannot make significant difference in terms of blood loss in patients undergoing Posterior Lumbar Inter body Fusion surgery,; however, some minor benefits in outcomes may lead to the selection of PCV rather than VCV. More studies with larger sample size, and investigating more factors may be needed. Declarations Ethical Approval The study protocol was approved by the Ethical committee of Kashan University of Medical Sciences, Kashan, Iran (reference number: IR.KAUMS.REC.1395.50). The study was registered at Iranian Registry of Clinical Trials (IRCT.IR). (IRCT Id: IRCT2016122731611N1, Registration date: 18/03/2017). CONSORT recommendations and guidelines were followed. Consent to participate All participants signed the informed consent form prior the study. Competing interests The authors have no relevant financial or non-financial interests to disclose. Authors' contributions M.H. designed and directed the study, analyzed the data, and interpreted the results. M.H.Z. contributed to the design of the work and interpretation of the results, drafted the manuscript, and revised the article. M.S. performed the experiments under supervision of M.H, did the measurements and collected the data. E.F. implemented the experiments and helped in data collection. All authors approved the final manuscript. Funding No funding Availability of data and materials Data used in this study can be accessed from the corresponding author. References Ristagno G, Beluffi S, Tanzi D, Belloli F, Carmagnini P, Croci M, et al. Red Blood Cell Transfusion Need for Elective Primary Posterior Lumbar Fusion in A High-Volume Center for Spine Surgery. Journal of clinical medicine. 2018;7(2). Malhotra A, Gupta V, Abraham M, Punetha P, Bundela Y. 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Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 12 Mar, 2023 Read the published version in European Journal of Medical Research → Version 1 posted Editorial decision: Major revision 02 Feb, 2023 Reviewers agreed at journal 03 Dec, 2022 Reviews received at journal 11 Oct, 2022 Reviewers agreed at journal 09 Oct, 2022 Reviewers invited by journal 08 Oct, 2022 Editor assigned by journal 06 Sep, 2022 Submission checks completed at journal 05 Sep, 2022 First submitted to journal 31 Aug, 2022 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-2016748","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":134190331,"identity":"be410778-38a7-4794-8bff-6c578a492c7c","order_by":0,"name":"Mohammad Hajijafari","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYDCCAwxsDAw8EswMzAcYGBIqGBgMiNfClgDUcoZoLSAA0sLYRoQWvtsH2B78kLFg529jfvbh4bzD8ubszQcYflRsw6lF8lwCu2EP0GESx9iMZyRuO2y4s+dYAmPPmds4tRicYWCT4AH55X6DMQNQC+OGGzkGzIxt+LVI/gFqkT/G/pkhcc5he6K0SINsMTjGA7Sl4XAiQS2SIC0yQC2Gx3iKGRKOpSdvOHMs4SA+v/CBHPa2py5Z7hj7ZsYfNda2G443H3zwowK3FgYG/g8MjD0MyVBeM5g8gEc9FPxgsIOy6ggrHgWjYBSMghEHAFQRVBgEMX+2AAAAAElFTkSuQmCC","orcid":"","institution":"anesthesiology department, Kashan university of medical sciences and health services","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Hajijafari","suffix":""},{"id":134190333,"identity":"6dd8f6b9-dda0-43a7-95d0-e85b5671d671","order_by":1,"name":"Mohammad Hossein Ziloochi","email":"","orcid":"","institution":"Department of Community Medicine, School of Medicine, Kashan University of Medical Sciences","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"Hossein","lastName":"Ziloochi","suffix":""},{"id":134190335,"identity":"de798426-a700-4544-b855-c3f93981d589","order_by":2,"name":"Manoochehr Salimian","email":"","orcid":"","institution":"KAUMS","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Manoochehr","middleName":"","lastName":"Salimian","suffix":""},{"id":134190338,"identity":"aac1515c-8a93-4866-aaa2-1f1bb775604a","order_by":3,"name":"Esmaeil Fakharian","email":"","orcid":"","institution":"KAUMS","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Esmaeil","middleName":"","lastName":"Fakharian","suffix":""}],"badges":[],"createdAt":"2022-08-31 07:59:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2016748/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2016748/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s40001-023-01080-z","type":"published","date":"2023-03-12T19:31:02+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":26216061,"identity":"0135f0e2-f355-41a5-8db0-9e40c50a8834","added_by":"auto","created_at":"2022-09-08 16:49:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":68512,"visible":true,"origin":"","legend":"\u003cp\u003eCONSORT flow diagram\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-2016748/v1/2c8877db87cd2606dd351896.png"},{"id":44721568,"identity":"163c49e2-2d5f-4998-bb0f-a1b30d625233","added_by":"auto","created_at":"2023-10-16 19:35:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":419093,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2016748/v1/e473ec12-e099-4232-9813-cf27784abc92.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Surgical Bleeding in Patients Undergoing Posterior Lumbar Inter body Fusion Surgery: A Randomized Clinical Trial Evaluating the Effect of Two Mechanical Ventilation Mode Types","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDemand for lumbar spine fusion, a common surgical procedure used for the treatment of many spinal conditions, has been increased in recent decades (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Although several surgical approaches exist for the interbody fusion, Posterior Lumbar Interbody Fusion (PLIF) is generally used due to its effective access and desirability of the surgical field (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). PLIF surgery may improve physical activity and satisfaction of patients with chronic back pain (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). However; surgical bleeding as a main concern in spine surgery has put lumbar spine fusion among the top 10 surgical procedures that necessitate blood transfusion (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan additionalcitationids=\"CR5 CR6 CR7 CR8\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eReduction of surgical blood loss is crucial to maintain hemodynamic stability and the desirability of the surgical field. Meanwhile, convenience of the surgeon is associated with reduction of intraoperative blood loss due to reduced operation time (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). Many factors contribute to the amount of intraoperative blood loss including sex, body mass index (BMI), the severity of deformity, surgical approach, number of levels, and anesthetic factors, such as the mode of mechanical ventilation (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eVolume-controlled ventilation (VCV), which is known as the classic ventilation mode, has been used for decades with a constant flow to deliver a target tidal volume and thus ensure satisfactory minute ventilation; however, using VCV mode may result in high airway pressure levels when chest compliance decreased, such as in obese patients, and lead to ventilation induced lung injury (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). Limited inspiratory pressure in pressure-controlled ventilation (PCV), an alternative mode of mechanical ventilation, may reduce the risk of barotrauma and volutrauma. It also ensures that collapsed alveoli open up by extending the inspiratory time using sufficient positive end expiratory pressure (PEEP) levels (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough there is no remarkable differences between the two ventilation modes, some researchers have carefully recommended changing the ventilation settings from VCV to PCV in some situations (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Regarding to bleeding outcome, some studies have particularly shown that using PCV can reduce intraoperative blood loss (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR19 CR20\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e); however, there are some controversies in this regard (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eConsidering the above-mentioned controversies, we carried out the present study to investigate the effect of mechanical ventilation mode on the outcomes in patients undergoing posterior lumbar inter body fusion (PLIF) in prone position. To reach this goal we compared VCV and PCV in terms of surgical outcomes. Our primary outcome was the amount of intraoperative blood loss. Secondary outcomes were heart rate, blood pressure, transfusion requirement, and surgeon satisfaction.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design and Population\u003c/h2\u003e \u003cp\u003eThis prospective, randomized, parallel and one-way blinded clinical trial, was conducted at Shahid Beheshti Hospital, a teaching hospital affiliated by Kashan University of Medical Sciences (KAUMS), Kashan, Iran; between 2017 and 2019.\u003c/p\u003e \u003cp\u003eTo recruit the participants, 100 patients with ASA class 1 and 2, aged between 18 and 75 years old, who were candidates for PLIF, were assessed. Among them, 22 patients were excluded. Exclusion criteria were: respiratory diseases like asthma and COPD (N\u0026thinsp;=\u0026thinsp;3), heart diseases such as heart failure, myocardial infarction, and valvar diseases (N\u0026thinsp;=\u0026thinsp;2), Coagulation diseases or anticoagulant consumption (N\u0026thinsp;=\u0026thinsp;5), BMI\u0026thinsp;\u0026gt;\u0026thinsp;30 (N\u0026thinsp;=\u0026thinsp;8), and history of any previous lumbar or chest surgery (N\u0026thinsp;=\u0026thinsp;4). After obtaining the written informed consent, the remained patients were randomly allocated into two groups of 39, namely VCV and PCV group (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe permuted block randomization was used for the participants\u0026rsquo; allocation (allocation ratio\u0026thinsp;=\u0026thinsp;1:1). To do this, a computer-generated list and sealed envelopes were used. All the patients were operated in prone position by one surgeon and a single surgical team using the same method. Although the surgeon and involved nurses were aware of the study, they were blinded to the details of the study\u0026rsquo;s protocol.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eEthics\u003c/h2\u003e \u003cp\u003eThis study was done from 2017 to 2019 at Shahid Beheshti Hospital, a teaching hospital affiliated by Kashan University of Medical Sciences (KAUMS). The study protocol was approved by the Ethics committee of KAUMS (Ethical code IR.KAUMS.REC.1395.50) All methods were carried out in accordance with relevant guidelines and regulations and with CONSORT recommendations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eAnesthetic protocol\u003c/h2\u003e \u003cp\u003eAttending anesthesiologist managed the anesthesia process. After establishing routine patient monitoring (heart rate, noninvasive blood pressure, pulse oximetry, and end tidal CO2), anesthesia was induced with an intravenous premedication of 2\u0026micro;g/kg fentanyl, 0.03 mg/kg midazolam, 5 mg/kg sodium thiopental, and 0.5 mg/kg atracurium. Endotracheal tube with a suitable size, a high-volume, and a low-pressure cuff was inserted for the patients. Invasive monitoring of blood pressure through radial artery were applied for all patients after induction. Anesthesia was maintained with infusion of propofol 100\u0026ndash;200 \u0026micro;g /Kg/min as well as 30/70% of O2/N2O mixture to maintain MAP around 70 mmHg.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003eIntervention\u003c/h2\u003e \u003cp\u003eIn PCV group, mechanical ventilation begun with PIP\u0026thinsp;=\u0026thinsp;15 mmHg, RR\u0026thinsp;=\u0026thinsp;12/min, I/E= \u0026frac12;, and PEEP\u0026thinsp;=\u0026thinsp;3. Then the PIP was adjusted to achieve a tidal volume that was calculated as the ideal body weight (50 [female: 45.5]\u0026thinsp;+\u0026thinsp;0.91 [height\u0026thinsp;\u0026minus;\u0026thinsp;152.4]) \u0026times; 7 ml. In addition, the respiratory rate was controlled, using the end-tidal carbon dioxide pressure (ETco2) ranged from 35 to 40 mmHg.\u003c/p\u003e \u003cp\u003eIn VCV group, TV was set as 7 ml/IBW; however, RR, I/E, and PEEP were chosen as PCV group. Afterward, anesthesia was reversed with 0.04 mg/Kg neostigmine and 0.02 mg /Kg atropine.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eOutcome measures\u003c/h2\u003e \u003cp\u003eAmount of intraoperative surgical bleeding, transfusion requirement, surgeon satisfaction, hemodynamic parameters, heart rate, blood pressure, and duration of surgery were measured. The amount of bleeding was calculated and registered based on the number of completely impregnated gauze pieces (15 cc for each 4 x 4 cm, and 50 cc for each 30 x 30 cm gauze piece), and the amount of blood in the suction bottle. Desirability of surgical field was recorded by the surgeon as good, moderate, or weak. Hemodynamic variables were recorded before the induction, after the intubation, after changing to prone position, every 15 minutes during the operation, at the end of surgery, after extubation, and before leaving the recovery unit. The surgeon and the staff who measured and recorded the hemodynamic variables were blinded to the mode of ventilation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eThe findings were analyzed using Kolmogorov-Smirnov test, t-test, Fisher\u0026rsquo;s exact test, and Chi-square test. SPSS-16 software was used to analyze data.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eDuring the study, 39 patients in each group of VCV and PCV were analyzed. The variables of sex, age, height, weight, and body mass index (BMI) were not significantly different between VCV and PCV groups; hence, two groups were comparable and similar in terms of demographic and anthropometric profiles (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u0026nbsp;\u003c/p\u003e\n\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\u003eDemographic and anthropometric profiles\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\u003eVCV group (n\u0026thinsp;=\u0026thinsp;39)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePCV group (n\u0026thinsp;=\u0026thinsp;39)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep-value\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\u003e\u003cstrong\u003eMale\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15(38.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16(41%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.82\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFemale\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24(61.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23(59%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (year)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.41\u0026thinsp;\u0026plusmn;\u0026thinsp;10.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.77\u0026thinsp;\u0026plusmn;\u0026thinsp;11.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.53\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eHeight(meter)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.65\u0026thinsp;\u0026plusmn;\u0026thinsp;.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.66\u0026thinsp;\u0026plusmn;\u0026thinsp;.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.54\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eWeight(kg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e76.11\u0026thinsp;\u0026plusmn;\u0026thinsp;11.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78.77\u0026thinsp;\u0026plusmn;\u0026thinsp;19.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e27.92\u0026thinsp;\u0026plusmn;\u0026thinsp;4.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.42\u0026thinsp;\u0026plusmn;\u0026thinsp;7.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.93\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e* Independent T test\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eTwo groups were also similar with respect to the number of surgical procedure level (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). \u0026nbsp;\u003c/p\u003e\n\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\u003enumber of surgical procedure level in studied groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003eNumber of levels\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"4\"\u003e\n \u003cp\u003e0.068\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003cp\u003e53.8%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003cp\u003e28.2%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003cp\u003e17.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003cp\u003e0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e2.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003cp\u003e70%%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e7.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003cp\u003e17.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e2.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e1.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003cp\u003e17.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003cp\u003e17.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003cp\u003e62%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e1.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003cp\u003e100%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"8\"\u003e* Fisher\u0026rsquo;s Exact test\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eTable \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e shows the amount of intraoperative surgical bleeding in the studied groups. Although PCV was associated with less bleeding (431.28 cc vs. 465.26 cc), the difference between two groups was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.67) (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). \u0026nbsp;\u003c/p\u003e\n\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\u003eMean blood loss in the studied groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP value*\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\u003e\u003cstrong\u003eVCV\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e465.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.67\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePCV\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e431.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e36.10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003e* Independent T test\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eTen patients in VCV group and 9 cases in PCV group required transfusion of one or two units of packed-cell. The average transfusion requirement in VCV and PCV groups were 0.43 and 0.40 unit respectively; however, there was no significant difference between two groups (p\u0026thinsp;=\u0026thinsp;1) (Table 4).\u0026nbsp;\u003c/p\u003e\n\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\u003epacked-cell units received by patients\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP value\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\u003eVCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29(74.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3(7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(17.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003csup\u003e\u003cstrong\u003e*\u003c/strong\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30(75%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3(10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6(15%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59(74.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6(8.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13(16.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e* Fisher\u0026rsquo;s Exact test\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eIn terms of surgical field desirability, the surgeon evaluated 82.1% of PCV and 74.4% of VCV cases as \u0026ldquo;Good\u0026rdquo;; however, the difference between two groups was not significant (p\u0026thinsp;=\u0026thinsp;0.58) (Table 5).\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab5\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003esurgeon satisfaction\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSurgeon satisfaction\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVCV Group\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePCV Group\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSum\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\u003eGood\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29(74.36%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32(82.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e61(78.2%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eModerate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9(23.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(17.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e16(20.5%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eweak\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1(2.56%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1(1.3%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e39(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e78(100%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0/58\u003csup\u003e*\u003c/sup\u003e\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 \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe patients who needed antihypertensive agents during the surgery were just two cases in PCV group. Although this number in VCV group was twice, the statistical test didn\u0026rsquo;t indicate a significant difference between two groups (p\u0026thinsp;=\u0026thinsp;0.22) (Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab6\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eneed for antihypertensive drugs during the surgery\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eNeed for Blood pressure-lowering drugs\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNo Need for Blood pressure-lowering drugs\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSum\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\" colspan=\"2\"\u003e\n \u003cp\u003eVCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e4(10.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35(89.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e39\u003c/strong\u003e(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e2(5.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37(94.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e39\u003c/strong\u003e(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSum\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e6(7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72(92.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e78\u003c/strong\u003e(100%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eP Value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003e0/22\u003csup\u003e*\u003c/sup\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"1\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\"\u003e* Chi Square\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eLike before surgery, measurement of mean hemoglobin in patients of two groups after the surgery showed no significant difference between two groups. (Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e). \u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab7\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eMean hemoglobin of patients before and after surgery in the study groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGroup\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP value\u003csup\u003e*\u003c/sup\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\" rowspan=\"2\"\u003e\n \u003cp\u003eBefore surgery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e0.772\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eAfter surgery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e0.775\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePCV\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e* Independent T test\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n\u003c/table\u003e\n\u003cp\u003eDiastolic blood pressure 90 and 105 min. after induction were significantly lower in PCV group (P\u0026thinsp;=\u0026thinsp;0.043 \u0026amp; 0.019 respectively); however, there were no significant difference between blood pressure in other times (Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e). Mean heart rate were also similar in two groups.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab8\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDiastolic blood pressure in studied groups throughout operative time\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\" name=\"Emphasis\" type=\"Underline\"\u003eVCV Group\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cspan class=\"Underline\" name=\"Emphasis\" type=\"Underline\"\u003ePCV Group\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eMean\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSD\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eP Value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBefore Induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e87.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e83.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.238\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfter Induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e74.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.361\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfter change of position\u003c/p\u003e\n \u003cp\u003e(from supine to prone)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e77.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e79.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.659\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.939\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.94\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.512\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e45 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e64.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.049\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e75 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60.90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.066\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66.79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.043\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e105 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e67.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.019\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e120 min.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.075\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEnd of Surgery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e65.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.049\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAfter repositioning (from prone to supine)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e73.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.168\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eExtubation Time\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.925\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRecovery\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e74.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.198\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cdiv type=\"Discussion\"\u003e\n \u003cp\u003eThis study was done to investigate the effect of mechanical ventilation mode on the outcomes in patients undergoing PLIF in prone position. As main outcomes, amount of intraoperative surgical bleeding, transfusion requirement, and surgeon satisfaction were compared in two groups of VCV and PCV. Hemodynamic parameters, heart rate, and blood pressure were also measured and compared in the two groups as other outcomes.\u003c/p\u003e\n \u003cp\u003ePCV group showed slightly better outcomes than VCV group in terms of mean blood loss (431 cc vs. 465 cc), transfusion requirement (0.40 vs. 0.43 unit), and satisfaction of the surgeon from surgical field (82.1% vs. 74.4%); however, the differences were not statistically significant.\u003c/p\u003e\n \u003cp\u003eZhendan Peng et al after a similar randomized controlled trial reported a similar result of less, but not significant blood loss in PCV group (13). Also, Lauren K. Dunn et al. in a retrospective study on a large sample size found that neither mode of mechanical ventilation nor airway pressure was associated with surgical bleeding or transfusion requirements (22).\u003c/p\u003e\n \u003cp\u003eHowever, there are some studies in which PCV has been reported to be significantly associated with lesser intraoperative blood loss (18\u0026ndash;20, 23). Reduced intraoperative blood loss has been argued to be related to decreased intrathoracic pressure and improved venous drainage which may be in turn due to decreased peak inspiratory pressure (PIP) during PCV (20, 21, 24).\u003c/p\u003e\n \u003cp\u003eTo explain the inconsistency of our results with studies that demonstrated significant lesser surgical bleeding during PCV, other factors influencing intraoperative blood loss should be considered. For example, age is an important factor that affects cardiovascular and coagulation status. The mean age of patients in our study was 42\u0026ndash;44 years, while the patients in Kang et al study aged more than 64 years old in average. Moreover, all patients in our study were operated in prone position, whereas in some studies the patient\u0026rsquo;s position during the surgery had been different. Length of surgery and number of surgical levels are among other factors that were different in our study and can explain our different results about surgical blood loss.\u003c/p\u003e\n \u003cp\u003eIn our study, diastolic blood pressures 90 and 105 min. after induction were significantly lower in PCV group (P\u0026thinsp;=\u0026thinsp;0.043 \u0026amp; 0.019 respectively); however, blood pressure in other times, hemoglobin levels, and mean heart rate were similar in two groups. Jun Han et al in a recently published systematic review and meta-analysis have presented that hemodynamics variables are not significantly related to mode of ventilation during spine surgery in prone position (23).\u003c/p\u003e\n \u003cp\u003eSome authors believe that because of hemodynamic stability and providing lower PIP, PCV is a better choice than VCV for patients undergoing lumbar spine fusion surgery (13, 20, 25, 26).\u003c/p\u003e\n \u003cp\u003eIn conclusion, this study suggests that mode of ventilation cannot make significant difference in terms of blood loss in patients undergoing Posterior Lumbar Inter body Fusion surgery,; however, some minor benefits in outcomes may lead to the selection of PCV rather than VCV. More studies with larger sample size, and investigating more factors may be needed.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Declarations","content":"\u003cdiv type=\"Discussion\"\u003e\n \u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe study protocol was approved by the Ethical committee of Kashan University of Medical Sciences, Kashan, Iran (reference number: IR.KAUMS.REC.1395.50). The study was registered at Iranian Registry of Clinical Trials (IRCT.IR). (IRCT Id: IRCT2016122731611N1, Registration date: 18/03/2017). CONSORT recommendations and guidelines were followed.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eAll participants signed the informed consent form prior the study.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eM.H. designed and directed the study, analyzed the data, and interpreted the results. M.H.Z. contributed to the design of the work and interpretation of the results, drafted the manuscript, and revised the article. M.S. performed the experiments under supervision of M.H, did the measurements and collected the data. E.F. implemented the experiments and helped in data collection. All authors approved the final manuscript.\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eNo funding\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003eData used in this study can be accessed from the corresponding author.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRistagno G, Beluffi S, Tanzi D, Belloli F, Carmagnini P, Croci M, et al. Red Blood Cell Transfusion Need for Elective Primary Posterior Lumbar Fusion in A High-Volume Center for Spine Surgery. Journal of clinical medicine. 2018;7(2).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMalhotra A, Gupta V, Abraham M, Punetha P, Bundela Y. Quantifying the amount of bleeding and associated changes in intra-abdominal pressure and mean airway pressure in patients undergoing lumbar fixation surgeries: a comparison of three positioning systems. Asian Spine Journal. 2016;10(2):199.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eResnick DK, Choudhri TF, Dailey AT, Groff MW, Khoo L, Matz PG, et al. Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 7: intractable low-back pain without stenosis or spondylolisthesis. Journal of Neurosurgery: Spine. 2005;2(6):670\u0026ndash;2.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoo JS, Ahn J, Karmarkar SS, Lamoutte EH, Singh K. The use of tranexamic acid in spine surgery. Annals of translational medicine. 2019;7(Suppl 5):S172.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNorton RP, Bianco K, Lafage V, Schwab FJ. Complications and intercenter variability of three-column resection osteotomies for spinal deformity surgery: a retrospective review of 423 patients. Evidence-based spine-care journal. 2013;4(02):157\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHorlocker TT, Nuttall GA, Dekutoski MB, Bryant SC. The accuracy of coagulation tests during spinal fusion and instrumentation. Anesthesia \u0026amp; Analgesia. 2001;93(1):33\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu SS. Blood loss in adult spinal surgery. European Spine Journal. 2004;13(1):S3-S5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCole JW, Murray DJ, Snider RJ, Bassett GS, Bridwell KH, Lenke LG. Aprotinin reduces blood loss during spinal surgery in children. Spine. 2003;28(21):2482\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSzpalski M, Gunzburg R, Sztern B. An overview of blood-sparing techniques used in spine surgery during the perioperative period. European spine journal. 2004;13(1):S18-S27.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJanatmakan F, Nesioonpour S, Zadeh FJ, Teimouri A, Vaziri M. Comparing the effect of clonidine and dexmedetomidine on intraoperative bleeding in spine surgery. Anesthesiology and pain medicine. 2019;9(1).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKelly MP, Lenke LG, Shaffrey CI, Ames CP, Carreon LY, Lafage V, et al. Evaluation of complications and neurological deficits with three-column spine reconstructions for complex spinal deformity: a retrospective Scoli-RISK-1 study. Neurosurgical focus. 2014;36(5):E17.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi Z-J, Fu X, Xing D, Zhang H-F, Zang J-C, Ma X-L. Is tranexamic acid effective and safe in spinal surgery? A meta-analysis of randomized controlled trials. European spine journal. 2013;22(9):1950\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePeng Z, Xia J, Yin N, Xue H. The effects of volume-controlled ventilation versus pressure-controlled ventilation on hemodynamic and respiratory parameters in patients undergoing lumbar spine fusion surgery: a randomized controlled trial. Annals of Palliative Medicine. 2021;10(9):9553\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMovassagi R, Montazer M, Mahmoodpoor A, Fattahi V, Iranpour A, Sanaie S. Comparison of pressure vs. volume controlled ventilation on oxygenation parameters of obese patients undergoing laparoscopic cholecystectomy. Pakistan journal of medical sciences. 2017;33(5):1117.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeininger D, Byhahn C, Mierdl S, Westphal K, Zwissler B. Positive end-expiratory pressure improves arterial oxygenation during prolonged pneumoperitoneum. Acta Anaesthesiologica Scandinavica. 2005;49(6):778\u0026ndash;83.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang J, Li B, Kang N, Wu A, Yue Y. Pressure-controlled versus volume-controlled ventilation for surgical patients: a systematic review and meta-analysis. Journal of Cardiothoracic and Vascular Anesthesia. 2016;30(2):501\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAl Shehri AM, El-Tahan MR, Al Metwally R, Qutub H, El Ghoneimy YF, Regal MA, et al. Right ventricular function during one-lung ventilation: effects of pressure-controlled and volume-controlled ventilation. Journal of Cardiothoracic and Vascular Anesthesia. 2014;28(4):880\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKundra S, Gupta R, Luthra N, Dureja M, Katyal S. Effects of ventilation mode type on intra-abdominal pressure and intra-operative blood loss in patients undergoing lumbar spine surgery: A randomised clinical study. Indian Journal of Anaesthesia. 2021;65(Suppl 1):S12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEl-Sayed AA, Arafa SK, El-Demerdash AM. Pressure-controlled ventilation could decrease intraoperative blood loss and improve airway pressure measures during lumbar discectomy in the prone position: A comparison with volume-controlled ventilation mode. Journal of Anaesthesiology, Clinical Pharmacology. 2019;35(4):468.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKang W-S, Oh C-S, Kwon W-K, Rhee KY, Lee YG, Kim T-H, et al. Effect of mechanical ventilation mode type on intra-and postoperative blood loss in patients undergoing posterior lumbar interbody fusion surgery: a randomized controlled trial. Anesthesiology. 2016;125(1):115\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLI N. Comparison of Effects of Pressure Controlled Ventilation and Volume Controlled Ventilation on Perioperative Blood Loss of Patients with Posterior Lumbar Interbody Fusion. Journal of Medical Research. 2017:154\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDunn LK, Taylor DG, Chen C-J, Singla P, Fern\u0026aacute;ndez L, Wiedle CH, et al. Ventilator mode does not influence blood loss or transfusion requirements during major spine surgery: a retrospective study. Anesthesia \u0026amp; Analgesia. 2020;130(1):100\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHan J, Hu Y, Liu S, Hu Z, Liu W, Wang H. Volume-controlled ventilation versus pressure-controlled ventilation during spine surgery in the prone position: A meta-analysis. Annals of Medicine and Surgery. 2022:103878.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim HB, Kweon TD, Chang CH, Kim JY, Kim KS. Equal Ratio Ventilation Reduces Blood Loss During Posterior Lumbar Interbody Fusion Surgery. Spine. 2021;46(16):E852.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChoi EM, Na S, Choi SH, An J, Rha KH, Oh YJ. Comparison of volume-controlled and pressure-controlled ventilation in steep Trendelenburg position for robot-assisted laparoscopic radical prostatectomy. Journal of clinical anesthesia. 2011;23(3):183\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJo YY, Kim JY, Kwak YL, Kim YB, Kwak HJ. The effect of pressure-controlled ventilation on pulmonary mechanics in the prone position during posterior lumbar spine surgery: a comparison with volume-controlled ventilation. Journal of Neurosurgical Anesthesiology. 2012;24(1):14\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Pressure-Controlled Ventilation, Volume-Controlled Ventilation, Posterior Lumbar Inter body Fusion, Surgical Blood Loss ","lastPublishedDoi":"10.21203/rs.3.rs-2016748/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2016748/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe purpose of the study was to compare the effect of using Volume-Controlled Ventilation (VCV) versus Pressure-Controlled Ventilation (PCV) on blood loss in patients undergoing Posterior Lumbar Inter body Fusion (PLIF) surgery.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eIn a randomized, single-blinded, parallel design, 78 patients candidate for PLIF surgery were randomly allocated into two groups of 39 to mechanically ventilated using VCV or PCV mode. All the patients were operated in prone position by one surgeon. Amount of intraoperative surgical bleeding, transfusion requirement, surgeon satisfaction, hemodynamic parameters, heart rate, and blood pressure were measured as outcomes.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePCV group showed slightly better outcomes than VCV group in terms of mean blood loss (431 cc vs. 465 cc), transfusion requirement (0.40 vs. 0.43 unit), and surgeon satisfaction (82.1% vs. 74.4%); however, the differences were not statistically significant. Diastolic blood pressure 90 and 105 min. after induction were significantly lower in PCV group (P\u0026thinsp;=\u0026thinsp;0.043 \u0026amp; 0.019 respectively); however, blood pressure in other times, hemoglobin levels, and mean heart rate were similar in two groups.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eIn patients undergoing Posterior Lumbar Inter body Fusion surgery, mode of ventilation cannot make significant difference in terms of blood loss; however, some minor benefits in outcomes may lead to the selection of PCV rather than VCV. More studies with larger sample size, and investigating more factors may be needed.\u003c/p\u003e","manuscriptTitle":"Surgical Bleeding in Patients Undergoing Posterior Lumbar Inter body Fusion Surgery: A Randomized Clinical Trial Evaluating the Effect of Two Mechanical Ventilation Mode Types","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-09-08 16:49:19","doi":"10.21203/rs.3.rs-2016748/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2023-02-02T12:33:28+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"1dbce1dd-1885-4c2a-ae73-4cfc41f39b82","date":"2022-12-03T12:53:27+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-10-11T16:00:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"abfa76ec-7c44-4bf8-8163-88b62447dbcd","date":"2022-10-09T07:24:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-10-08T15:44:25+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-09-06T07:19:22+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-09-05T09:58:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Medical Research","date":"2022-08-31T07:53:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b5484c24-6c7a-4fb1-a008-c6db9673c66b","owner":[],"postedDate":"September 8th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T19:33:58+00:00","versionOfRecord":{"articleIdentity":"rs-2016748","link":"https://doi.org/10.1186/s40001-023-01080-z","journal":{"identity":"european-journal-of-medical-research","isVorOnly":false,"title":"European Journal of Medical Research"},"publishedOn":"2023-03-12 19:31:02","publishedOnDateReadable":"March 12th, 2023"},"versionCreatedAt":"2022-09-08 16:49:19","video":"","vorDoi":"10.1186/s40001-023-01080-z","vorDoiUrl":"https://doi.org/10.1186/s40001-023-01080-z","workflowStages":[]},"version":"v1","identity":"rs-2016748","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2016748","identity":"rs-2016748","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}