Correlation Between Perioperative Hemodynamics and Flap outcome in Microvascular Flap Reconstruction – A Retrospective Study

Correlation Between Perioperative Hemodynamics and Flap outcome in Microvascular Flap Reconstruction – A Retrospective Study | 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 Correlation Between Perioperative Hemodynamics and Flap outcome in Microvascular Flap Reconstruction – A Retrospective Study Manjula Sudhakar Rao, Shruthi G Raikar, Ijaz Ahamed, Deviprasad S, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6246819/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 Background Microvascular free flap reconstruction is a complex surgical procedure used to repair tissue defects from trauma, oncology, or chronic wounds. Despite advancements in surgical techniques, flap failure due to hypoperfusion and necrosis remains a challenge. Hemodynamic stability during the perioperative period is a key determinant of flap survival, but the influence of anaesthetic management on flap outcomes is not well studied. Objective To analyse the impact of intraoperative hemodynamic stability and anaesthetic factors on the success of microvascular free flap reconstruction. Methods A retrospective study was conducted in a tertiary hospital in India from March 2023 to April 2024. A total of 30 patients (aged 25–75 years) undergoing elective microvascular free flap reconstruction under general anaesthesia were included. Hemodynamic parameters (blood pressure, heart rate), arterial blood gas (ABG) values, and flap outcomes were recorded preoperatively, intraoperatively, and postoperatively. Statistical analysis was performed using SPSS version 23.0, with significance set at p ≤ 0.05. Results The overall success rate of free flap reconstruction was 90%. No significant differences in intraoperative systolic and diastolic blood pressure were observed between the success and failure groups, except at the time of anastomosis (SBP: p < 0.001, DBP: p < 0.001) and postoperatively (SBP: p < 0.001, DBP: p < 0.001). Use of noradrenaline to manage intraoperative hypotension did not negatively affect flap survival. Excessive fluid administration was associated with flap edema and increased failure risk. Conclusion Perioperative hemodynamic stability is critical for successful microvascular free flap outcomes. Noradrenaline is a safe and effective agent for maintaining blood pressure without compromising flap viability. Careful fluid management and stable hemodynamic control are essential to optimize flap survival rates. Further studies with larger sample sizes are warranted to validate these findings. Microvascular flap reconstruction Flap anaesthesia reconstructive surgery general anaesthesia Introduction Microvascular flap reconstruction is one of the greatest achievements in surgical field to achieve the closure of various tissue defects. These defects maybe caused due to various etiological factors such as trauma, oncology, chronic infection or wounds. (1) Free tissue transfer, in contrast to conventional surgical techniques provide a reliable and wide range of donor sites, resulting in improved flap characteristics. (2) The advantages of free flap being early mobilisation, reduced hospital stay and cost. However, due to its complex surgical technique, problems of hypoperfusion and flap necrosis continue to be a major problem, despite improvements in surgical skills. (3) Numerous non-surgical factors determine the survival of free flap, including age, comorbid condition, haemodynamic status, rheology, temperature regulation, anticoagulants and other vasogenic drugs. Maintaining the hemodynamic stability and regional blood flow in the intra – operative period with anaesthetic agents is an important determinant factor in the success of free flap. The Hagen – Poiseuille’s equation helps in understanding the factors that determine the blood flow of the newly vascularised tissue. The viability of the free flap is majorly influenced by the haemodynamic stability of the patient in the perioperative period. The major determinant of the success of free flap includes the use of vasoactive drugs, changes in blood volume and the maintenance of microcirculation in the peri operative period. Preoperative evaluation and optimisation of the current comorbidities of patient is at most important prior to surgery. Intraoperative Optimisation of blood pressure and fluid management to maintain high cardiac output and low systemic vascular resistance is crucial to ensure the success of the flap. Both hypotension and hypoperfusion can be harmful to the flap, hence it is important to maintain stable hemodynamic during the surgery and in the early recovery phase. Perioperative care in a multidisciplinary team – based approach could improve the results of microvascular flap surgery. There are many literatures supporting the surgical factors influencing the viability of microvascular free flap, but there are very few studies regarding the influence of anaesthetic factors on the outcome of flap. Hence this retrospective study was conducted to analyse the hemodynamic changes and the free flap outcome. Materials and Methods A retrospective study was conducted in a tertiary hospital in India, from March 2023 to April 2024 after the data was collected and its analysis was done. A total of 30 patients were included in the study who underwent microvascular free flap reconstruction in the Department of Plastic surgery. All the patients who fit into the inclusion criteria during the stated period of time form the sample population. Inclusion criteria: Patients in the age group 25-75years undergoing elective microvascular free flap reconstruction under General anaesthesia; ASA class I& II; Surgical duration less than 8 hours. Exclusion criteria: ASA class III and IV.; Emergency surgeries and prior free flap failure; Coagulopathy (INR > 1.5, platelets < 100,000).; Surgery going beyond 8 hours; Severe vascular disease, pregnancy, chronic vasopressor/immunosuppressive use. A qualified, experienced plastic surgeon performed the procedure. Pre induction standard ASA monitors, including ECG, NIBP, SpO₂, and capnography, were applied, and an arterial line was placed under local anesthesia (2% lignocaine, 1–2 mL) before induction for continuous blood pressure monitoring. Premedication included glycopyrrolate 0.2 mg IV, midazolam 1–2 mg IV, and morphine 0.1 mg/kg IV, followed by induction with propofol 2 mg/kg IV. Nasotracheal intubation using a nasal RAE tube was performed after administering vecuronium 0.1 mg/kg IV. Anesthesia was maintained with isoflurane at 1 MAC, and ventilation was set to volume-controlled mode with tidal volume 6–8 ml/kg, respiratory rate of 12–14/min and airway pressure targeted to P max of 15–25 cm of H2O, FiO₂ 50% and EtCO₂ maintained between 35–40 mmHg. Intraoperatively, SBP was maintained between 100–130 mmHg, using intermittent boluses of propofol (20mg IV) if SBP exceeded 130 mmHg and fluid therapy was carefully titrated with balanced crystalloids (Ringer’s lactate or Plasmalyte) to prevent excessive resuscitation and flap edema, if SBP dropped below 100 mmHg followed by noradrenaline infusion (0.03–0.05 mcg/kg/min) if the SBP did not respond to fluid resuscitation. The anaesthesiologist monitored and maintained the hemodynamic stability using fluids and inotropic agents and recorded the variation in vitals during the procedure and post procedure. Postoperatively, the patient was shifted to the ICU for continuous hemodynamic monitoring and flap assessment. The patient remained paralyzed and sedated under controlled ventilation to optimize flap perfusion and minimize metabolic demand. Sedation was maintained with fentanyl (1–2 mcg/kg/hr) and midazolam (0.02–0.05 mg/kg/hr) infusions, while muscle paralysis was achieved with a vecuronium infusion (0.8–1.2 mcg/kg/min). Throughout the night, the patient was closely monitored for stable hemodynamics, adequate oxygenation, and flap viability, with regular assessments of temperature, capillary refill, ABG and flap glucose levels. The next morning, following a detailed flap assessment, sedation and paralysis were gradually tapered, the patient was weaned off mechanical ventilation, and extubated once stable. Post-extubation, the patient was provided supplemental oxygen and continued ICU monitoring to ensure optimal recovery and flap viability. Data was collected on gender, age, Preinduction, post induction, intraoperative upto 6 hours, and post operative Blood pressure and heart rate, pre operative and post operative ABG reports. All statistical analyses have been performed with SPSS version 23.0. Statistical significance was determined using independent t-test for continuous data. A p-value of ≤ 0.05 was regarded as statistically significant. Results A total of 30 patients were included in the study. The average age among participants was 45.6 ± 10.1 years old. The eldest participant was 62 years old, and the youngest was 25 years old. (Table 1 ) The average heart rate ranged from 75 to 95 bpm, with higher values seen during anastomosis. The comparison of average heart rate at specific intervals between successful and failed cases was not found to be statistically significant. Table 1 Sociodemographic profile of participants Variables Sex Re – exploration status Flap Outcome Blood Transfusion Ionotropic Support F M No Yes Successful Failure No Yes No Yes n 9 21 23 7 27 3 20 10 24 6 % 30 70 76.7 23.3 90 10 66.7 33.3 80 20 No significant differences (p > 0.05) in SBP and DBP between the Success and Failure groups was noted from pre induction to 6 hours post induction. Some borderline differences are noted at 2 hours (SBP, p = 0.060) and 5 hours (SBP, p = 0.054), but these are not statistically significant. Post-Operatively, there is a significant increase in SBP (p < 0.001) and DBP (p < 0.001) in the Failure group, indicating a substantial rise in blood pressure. At Dissection, the Failure group had a significantly higher SBP (p = 0.021) but no significant DBP difference. At Anastomosis, there is a highly significant increase in both SBP (p < 0.001) and DBP (p < 0.001) in the Failure group compared to the Success group. (Table 2 ) Table 2 Comparison of SBP and DBP among successful and failed attempt cases at specific intervals BP SBP DBP Success Failure P value* Success Failure P value* Mean SD Mean SD Mean SD Mean SD Pre induction 123.37 8.92 132 9.89 0.910 80.7 7.47 72.67 1.52 0.078 Post-induction 110.78 5.79 113.5 7.77 0.782 71.7 8.17 77.33 14.15 0.299 1 hour 124.56 10.1 127.5 16.26 0.428 80.81 6.08 80.67 9.5 0.970 2 hour 124.11 9.25 117 2.82 0.060 80.52 5.63 77.33 8.08 0.378 3hour 124.70 8.71 120 11.31 0.883 80.22 6.69 84.33 7.23 0.325 4hour 127.44 9.91 116.5 9.19 0.578 80.52 5.91 78.67 4.16 0.604 5hour 124.45 9.22 114 2.67 0.054 79.89 5.35 82.33 6.42 0.467 6hour 122.15 8.71 117.5 3.53 0.138 81.26 5.88 80.67 4.72 0.868 Post-op 125.52 8.32 164 6.98 < 0.001 77.3 7.28 96 3.46 < 0.001 At Dissection 122.26 10.52 131.5 0.71 0.021 80.52 6.32 77.67 9.86 0.486 At Anastomosis 121.52 6.42 168.67 3.05 < 0.001 76.41 7.5 96 2 < 0.001 *Independent T-test Table 3 Comparison of Blood transfusion among successful and failed cases Blood Transfusion Successful Failure P – value* n % n % 0.223 No 18 66.7 2 66.7 Yes 9 33.3 1 33.3 *Chi – square test No statistically significant difference was noted in the success and failure group, if blood transfusion was given or not given after the flap reconstruction. (Table 3 ) No statistically significant differences between Success and Failure groups for pH, CO₂, and HCO₃, indicating similar respiratory and metabolic conditions. Lactate levels tend to be lower in the Failure group pre- and post-operatively, but this is not statistically significant. The Failure group showed a slight post-op pH increase (alkalosis), which might suggest a physiological response to stress or interventions like hyperventilation. (Table 4 ) Table 4 Comparison of ABG values among successful and failed attempt cases ABG values Success Failure P value* Mean SD Mean SD Pre-operative values pH 7.39 0.03 7.37 0.02 0.332 CO2 40.05 2.83 38.63 3.03 0.419 HCO3 24.01 1.17 23.53 1 0.502 Lactates 1.35 0.5 1.44 0.15 0.774 Post-operative values pH 7.39 0.03 7.42 0.03 0.15 CO2 39.75 2.91 40.06 2.7 0.85 HCO3 23.88 1.17 23.7 1.68 0.8 Lactates 1.43 0.48 2.34 0.05 < 0.05 *Independent T - test Discussion During microvascular free flap reconstruction, optimal blood pressure control during the perioperative period is crucial to minimise patient morbidity and maximize free flap survival. 4 , 5 However, during induction and intraoperatively period, the general anaesthetic agents tend to induce systemic hypotension which can result in hypoperfusion of critical organs and the flap itself. The overall success rate of free flap noted in our study was 90%, which was similar to the reported rate in most previously published studies. 3 The effects of different anaesthetic agents on the microvascular parameter of the free flap and its fluid distribution remain unclear. 6 , 7 Studies have shown that the use of sevoflurane compared with intravenous anaesthetics such as propofol has shown beneficial effects on microcirculation, reducing the plasma leakage into interstitial space and decreasing oedema. There is evidence showing the beneficial effects of inhalational agents on different mechanisms of ischaemia–reperfusion injury. 8 – 10 In this study, all the patients were maintained with inhalational anaesthesia isoflurane with MAC of 1 and intermittent bolus dose of 20mg intravenous propofol to maintain the systolic blood pressure less than 130mmHg. Intraoperative hypotension may be dealt with by reducing the dosage of anaesthetic agents or increasing the volume of intravenous fluids. Reducing the dosage of anaesthetic agents is not feasible as a certain depth of anaesthesia needs to be maintained intraoperatively. Overzealous use of intravenous fluids may cause pulmonary oedema with resultant cardiopulmonary decompensation. Intravenous fluid infusion is associated with flap oedema and surrounding tissue oedema, which progressively impair flap microcirculation by mechanical compression of the microvasculature or pedicle vessels. 11 , 12 The free flap lacks lymphatic drainage and denervation of the free flap decreases interstitial fluid reabsorption, causing the free flap more prone to graft oedema, contributing to adverse flap outcomes. 13 , 14 Perioperative overzealous use of fluids is also associated with increased anastomotic thrombosis, flap complications and medical complications. 11 , 14 The use of vasopressor may be necessary in certain situations to maintain an acceptable mean blood pressure. Spectral analysis of laser Doppler blood flow signals in free flap reconstruction patients has demonstrated that the use of norepinephrine, and control of blood flow shifted towards low-frequency vasomotion where blood flow depended mostly on an average blood pressure. Hence, the use of noradrenaline could be considered the most suitable agent following free flap reconstruction. 15 In this study, the success group had stable blood pressure throughout the surgery, but on the contrary, the failure group had a drop in blood pressure post-induction. The blood pressure in the failure group was increased by giving intraoperative fluids and starting the patient on noradrenaline inotropic agents. There were 3 cases in the success group, where the use of noradrenaline inotropic agents to increase blood pressure had no adverse flap outcome. The use of noradrenaline is noted to increase the free flap skin blood flow more when compared to other vasopressor agents, making it the most suitable inotropic agent during hypotension in patients undergoing free flap reconstruction. The noradrenaline acts on both alpha – 1 and alpha – 2 adrenergic receptors to cause vasoconstriction and thereby increase blood pressure. In a retrospective review by Kelly et al ., on the impact of intraoperative vasopressor use in free tissue transfer during the head, neck, and extremity reconstruction, it was found that the frequency of vasopressor use was 53.2% with no significant difference in flap outcome in patients who received vasopressors and those who did not. 16 Another randomized controlled trial in patients undergoing ablative and reconstructive headandneck surgery with microvascular flap also showed noradrenaline to be safe and effective for use in the postoperative period when used to maintain MAP between 80 and 90 mmHg. 17 The common cause of flap failure seen in the literature is multifactorial such as arterial (arterial thrombosis, vasospasm), venous (venous thrombosis, vasospasm, mechanical compression), flap oedema (overzealous use of fluids, hemodilution), generalised vasoconstriction (hypothermia, pain, respiratory alkalosis), hypotension (hypovolemia, myocardial depressants) and prolonged ischemia of the flap. 18 Venous thrombosis is noted to be the most common cause of flap failure followed by arterial obstruction. Conclusion This study emphasizes the critical role of perioperative hemodynamic stability in optimizing free flap survival during microvascular free flap reconstruction. A stable hemodynamic profile was noted in the success group, whereas the failure group exhibited intraoperative hypotension that required intravenous fluids administration and use of noradrenaline inotropic support. Despite concerns regarding vasopressor use, our findings, along with evidence from previous studies, indicate that noradrenaline is a safe and effective agent for maintaining adequate mean arterial pressure (MAP) without compromising flap viability. Inhalational anesthesia, particularly sevoflurane, appears to offer beneficial effects on microcirculation, potentially reducing flap edema and ischemia–reperfusion injury. However, excessive intravenous fluid administration should be avoided due to its association with flap edema and increased risk of anastomotic thrombosis. Flap failure is multifactorial commonly attributed to venous thrombosis, arterial thrombosis, vasospasm, and mechanical compression a comprehensive approach involving meticulous intraoperative monitoring, judicious fluid management, and appropriate vasopressor use is essential for improving free flap survival rates. Future studies with larger sample sizes and randomized controlled trials are warranted to further refine perioperative management strategies and optimize surgical outcomes. Declarations Ethics approval and consent to participate – obtained by yenepoya ethical committee Consent for publication – obtained from the participants Availability of data and materials – The datasets generated and/or analysed during the current study are not publicly available due to the nondisclosure of personal data of participants in the public domain but are available from the corresponding author on reasonable request. Competing interests – I declare that there are no competing interests Funding – not applicable Authors' contributions – MSR - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient SGR - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient IA - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient DS - Surgeon performing the operation on the patient AR - Surgeon performing the operation on the patient Acknowledgements – Not applicable References Min, K.; Hong, J.P.; Suh, H.P. Risk Factors for Partial Flap Loss in a Free Flap: A 12-Year Retrospective Study of Anterolateral Thigh Free Flaps in 303 Lower Extremity Cases. Plast. Reconstr. Surg. 2022 , 150, 1071e–1081e. [CrossRef] [PubMed] Wei, F.C.; Lin Tay, S.K.; Al Deek, N.F. Principles and techniques of microvascular surgery. Plast. Surg. 2024 , 25, 414–415. Jayaram K, Rao P, Gurajala I, Ramachandran G. Evaluation of the Effect of Regional Anaesthesia on Microvascular Free Flaps. Turk J Anaesthesiol Reanim 2018; 46(6): 441-6. Chen C, Nguyen MD, Bar-Meir E, et al. Effects of vasopressor administration on the outcomes of microsurgical breast reconstruction. Ann Plast Surg 2010;65(01):28–31 Haughey BH, Wilson E, Kluwe L, et al. Free flap reconstruction of the head and neck: analysis of 241 cases. Otolaryngol Head Neck Surg 2001;125(01):10–17 Sigurdsson GH, Thomson D. Anaesthesia and microvascular surgery: Clinical practice and research. Eur J Anaesthesiol 1995; 12: 101-22. Hahn RG. Microvascular changes and anaesthesia. Acta Anaesthesiol Scand 2002; 46: 479-80. [CrossRef] Bruegger D, Bauer A, Finsterer U, Bernasconi P, Kreimeier U, Christ F. Microvascular changes during anaesthesia: Sevoflurane compared with propofol. Acta Anaesthesiol Scand 2002; 46: 481-7. [CrossRef] Preckel B, Schlack W, Comfere T, Obal D, Barthel H, Thamer V. Effects of enflurane, isoflurane, sevoflurane, and desflurane on reperfusion injury after regional myocardial ischaemia in the rabbit heart in vivo. Br J Anaesth 1998; 81: 905-12. [CrossRef] Piriou V, Chiari P, Lhuillier F, Bastien O, Loufoua J, Raisky O, et al. Pharmacological preconditioning: Comparison of desflurane, sevoflurane, isoflurane and halothane in rabbit myocardium. Br J Anaesth 2002; 89: 486-91. [CrossRef] Haughey BH, Wilson E, Kluwe L, et al. Free flap reconstruction of the head and neck: analysis of 241 cases. Otolaryngol Head Neck Surg 2001;125(01):10–17 Wei FC, Mardini S. Flaps and Reconstructive Surgery. 1st ed. Philadelphia, PA: Saunders (Imprint), Elsevier; 2009 Sigurdsson GH. Perioperative fluid management in microvascular surgery. J Reconstr Microsurg 1995;11(01):57–65 Booi DI. Perioperative fluid overload increases anastomosis thrombosis in the free TRAM flap used for breast reconstruction. Eur J Plast Surg 2011;34(02):81–86 Eley KA, Young JD, Watt‑Smith SR. Power spectral analysis of the effects of epinephrine, norepinephrine, dobutamine and dopexamine on microcirculation following free tissue transfer. Microsurgery 2013;33:275‑81 Kelly DA, Reynolds M, Crantford C, Pestana IA. Impact of intraoperative vasopressor use in free tissue transfer for head, neck, and extremity reconstruction. Ann Plast Surg 2014;72:S135‑8. Raittinen L, Kääriäinen MT, Lopez JF, Pukander J, Laranne J. The effect of norepinephrine and dopamine on radial forearm flap partial tissue oxygen pressure and microdialysate metabolite measurements: A randomized controlled trial. Plast Reconstr Surg 2016;137:1016e‑23e. Adams J, Charlton P. Anesthesia for microvascular free tissue transfer. Br J Anaesth (CEPD Reviews) 2003;3:33‑7. Additional Declarations No competing interests reported. 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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-6246819","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":434191511,"identity":"7e616629-6e91-4dd4-902f-1d6184148125","order_by":0,"name":"Manjula Sudhakar Rao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA90lEQVRIiWNgGAWjYJACA4YCIJYAMSuAmJm5gQgtBjAtZ0BaGAlrYYBrYWwD8Qho0W0/e6CYx4DBWH5289ENP+fVRvO3A7X8qNiGU4vZmbwEY6AWM4M7x9Ju9m47njvjMGMDY8+Z27i1HMgxAGmxMZDIMbvBu+1YbgNQCzNjGx4t599AtMjPyP928++cY7nzCWq5AbHFjOFGDttt3oaa3A2EtbwxMJxjIGFscCPN7LbMsQO5G4FaDuL1y/kcM4M3FTaG82ckP7v5pqYud975wwcf/KjArQUI2AwYIPEIAofB5AF86oGA+QESp46A4lEwCkbBKBiJAACCIVquv3KRUgAAAABJRU5ErkJggg==","orcid":"","institution":"Yenepoya University","correspondingAuthor":true,"prefix":"","firstName":"Manjula","middleName":"Sudhakar","lastName":"Rao","suffix":""},{"id":434191512,"identity":"e1e32646-8099-4b1d-bdd5-6bf43381a704","order_by":1,"name":"Shruthi G Raikar","email":"","orcid":"","institution":"Yenepoya University","correspondingAuthor":false,"prefix":"","firstName":"Shruthi","middleName":"G","lastName":"Raikar","suffix":""},{"id":434191513,"identity":"fce9597b-d31f-4a5e-bd09-cee8148adefb","order_by":2,"name":"Ijaz Ahamed","email":"","orcid":"","institution":"Yenepoya University","correspondingAuthor":false,"prefix":"","firstName":"Ijaz","middleName":"","lastName":"Ahamed","suffix":""},{"id":434191514,"identity":"66735a5e-cd7e-4b7c-bc6c-7dea2eb96063","order_by":3,"name":"Deviprasad S","email":"","orcid":"","institution":"Yenepoya University","correspondingAuthor":false,"prefix":"","firstName":"Deviprasad","middleName":"","lastName":"S","suffix":""},{"id":434191515,"identity":"4f7f5466-0941-4440-a09a-d39342b08578","order_by":4,"name":"Amar Rao","email":"","orcid":"","institution":"Yenepoya University","correspondingAuthor":false,"prefix":"","firstName":"Amar","middleName":"","lastName":"Rao","suffix":""}],"badges":[],"createdAt":"2025-03-17 17:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6246819/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6246819/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":83170929,"identity":"637e9edb-526d-44dd-a200-1f0ece5dd3e2","added_by":"auto","created_at":"2025-05-20 17:31:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":681127,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6246819/v1/7174c0c6-947c-46fb-b918-ddd8a2bf2689.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Correlation Between Perioperative Hemodynamics and Flap outcome in Microvascular Flap Reconstruction – A Retrospective Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMicrovascular flap reconstruction is one of the greatest achievements in surgical field to achieve the closure of various tissue defects. These defects maybe caused due to various etiological factors such as trauma, oncology, chronic infection or wounds. \u003csup\u003e(1)\u003c/sup\u003e Free tissue transfer, in contrast to conventional surgical techniques provide a reliable and wide range of donor sites, resulting in improved flap characteristics. \u003csup\u003e(2)\u003c/sup\u003e The advantages of free flap being early mobilisation, reduced hospital stay and cost. However, due to its complex surgical technique, problems of hypoperfusion and flap necrosis continue to be a major problem, despite improvements in surgical skills. \u003csup\u003e(3)\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eNumerous non-surgical factors determine the survival of free flap, including age, comorbid condition, haemodynamic status, rheology, temperature regulation, anticoagulants and other vasogenic drugs. Maintaining the hemodynamic stability and regional blood flow in the intra \u0026ndash; operative period with anaesthetic agents is an important determinant factor in the success of free flap.\u003c/p\u003e \u003cp\u003eThe Hagen \u0026ndash; Poiseuille\u0026rsquo;s equation helps in understanding the factors that determine the blood flow of the newly vascularised tissue. The viability of the free flap is majorly influenced by the haemodynamic stability of the patient in the perioperative period. The major determinant of the success of free flap includes the use of vasoactive drugs, changes in blood volume and the maintenance of microcirculation in the peri operative period.\u003c/p\u003e \u003cp\u003ePreoperative evaluation and optimisation of the current comorbidities of patient is at most important prior to surgery. Intraoperative Optimisation of blood pressure and fluid management to maintain high cardiac output and low systemic vascular resistance is crucial to ensure the success of the flap. Both hypotension and hypoperfusion can be harmful to the flap, hence it is important to maintain stable hemodynamic during the surgery and in the early recovery phase. Perioperative care in a multidisciplinary team \u0026ndash; based approach could improve the results of microvascular flap surgery.\u003c/p\u003e \u003cp\u003eThere are many literatures supporting the surgical factors influencing the viability of microvascular free flap, but there are very few studies regarding the influence of anaesthetic factors on the outcome of flap. Hence this retrospective study was conducted to analyse the hemodynamic changes and the free flap outcome.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eA retrospective study was conducted in a tertiary hospital in India, from March 2023 to April 2024 after the data was collected and its analysis was done. A total of 30 patients were included in the study who underwent microvascular free flap reconstruction in the Department of Plastic surgery. All the patients who fit into the inclusion criteria during the stated period of time form the sample population.\u003c/p\u003e \u003cp\u003eInclusion criteria: Patients in the age group 25-75years undergoing elective microvascular free flap reconstruction under General anaesthesia; ASA class I\u0026amp; II; Surgical duration less than 8 hours.\u003c/p\u003e \u003cp\u003eExclusion criteria: ASA class III and IV.; Emergency surgeries and prior free flap failure; Coagulopathy (INR\u0026thinsp;\u0026gt;\u0026thinsp;1.5, platelets\u0026thinsp;\u0026lt;\u0026thinsp;100,000).; Surgery going beyond 8 hours; Severe vascular disease, pregnancy, chronic vasopressor/immunosuppressive use.\u003c/p\u003e \u003cp\u003eA qualified, experienced plastic surgeon performed the procedure. Pre induction standard ASA monitors, including ECG, NIBP, SpO₂, and capnography, were applied, and an arterial line was placed under local anesthesia (2% lignocaine, 1\u0026ndash;2 mL) before induction for continuous blood pressure monitoring. Premedication included glycopyrrolate 0.2 mg IV, midazolam 1\u0026ndash;2 mg IV, and morphine 0.1 mg/kg IV, followed by induction with propofol 2 mg/kg IV. Nasotracheal intubation using a nasal RAE tube was performed after administering vecuronium 0.1 mg/kg IV. Anesthesia was maintained with isoflurane at 1 MAC, and ventilation was set to volume-controlled mode with tidal volume 6\u0026ndash;8 ml/kg, respiratory rate of 12\u0026ndash;14/min and airway pressure targeted to P max of 15\u0026ndash;25 cm of H2O, FiO₂ 50% and EtCO₂ maintained between 35\u0026ndash;40 mmHg. Intraoperatively, SBP was maintained between 100\u0026ndash;130 mmHg, using intermittent boluses of propofol (20mg IV) if SBP exceeded 130 mmHg and fluid therapy was carefully titrated with balanced crystalloids (Ringer\u0026rsquo;s lactate or Plasmalyte) to prevent excessive resuscitation and flap edema, if SBP dropped below 100 mmHg followed by noradrenaline infusion (0.03\u0026ndash;0.05 mcg/kg/min) if the SBP did not respond to fluid resuscitation. The anaesthesiologist monitored and maintained the hemodynamic stability using fluids and inotropic agents and recorded the variation in vitals during the procedure and post procedure.\u003c/p\u003e \u003cp\u003ePostoperatively, the patient was shifted to the ICU for continuous hemodynamic monitoring and flap assessment. The patient remained paralyzed and sedated under controlled ventilation to optimize flap perfusion and minimize metabolic demand. Sedation was maintained with fentanyl (1\u0026ndash;2 mcg/kg/hr) and midazolam (0.02\u0026ndash;0.05 mg/kg/hr) infusions, while muscle paralysis was achieved with a vecuronium infusion (0.8\u0026ndash;1.2 mcg/kg/min). Throughout the night, the patient was closely monitored for stable hemodynamics, adequate oxygenation, and flap viability, with regular assessments of temperature, capillary refill, ABG and flap glucose levels. The next morning, following a detailed flap assessment, sedation and paralysis were gradually tapered, the patient was weaned off mechanical ventilation, and extubated once stable. Post-extubation, the patient was provided supplemental oxygen and continued ICU monitoring to ensure optimal recovery and flap viability.\u003c/p\u003e \u003cp\u003eData was collected on gender, age, Preinduction, post induction, intraoperative upto 6 hours, and post operative Blood pressure and heart rate, pre operative and post operative ABG reports.\u003c/p\u003e \u003cp\u003eAll statistical analyses have been performed with SPSS version 23.0. Statistical significance was determined using independent t-test for continuous data. A p-value of \u0026le;\u0026thinsp;0.05 was regarded as statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 30 patients were included in the study. The average age among participants was 45.6\u0026thinsp;\u0026plusmn;\u0026thinsp;10.1 years old. The eldest participant was 62 years old, and the youngest was 25 years old. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) The average heart rate ranged from 75 to 95 bpm, with higher values seen during anastomosis. The comparison of average heart rate at specific intervals between successful and failed cases was not found to be statistically significant.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSociodemographic profile of participants\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariables\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eRe \u0026ndash; exploration status\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eFlap Outcome\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eBlood Transfusion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003eIonotropic Support\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eM\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSuccessful\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFailure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003en\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e%\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e76.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e23.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e66.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e33.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNo significant differences (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) in SBP and DBP between the Success and Failure groups was noted from pre induction to 6 hours post induction. Some borderline differences are noted at 2 hours (SBP, p\u0026thinsp;=\u0026thinsp;0.060) and 5 hours (SBP, p\u0026thinsp;=\u0026thinsp;0.054), but these are not statistically significant.\u003c/p\u003e \u003cp\u003ePost-Operatively, there is a significant increase in SBP (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and DBP (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) in the Failure group, indicating a substantial rise in blood pressure. At Dissection, the Failure group had a significantly higher SBP (p\u0026thinsp;=\u0026thinsp;0.021) but no significant DBP difference. At Anastomosis, there is a highly significant increase in both SBP (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and DBP (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) in the Failure group compared to the Success group. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of SBP and DBP among successful and failed attempt cases at specific intervals\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eBP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003eSBP\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c11\" namest=\"c7\"\u003e \u003cp\u003eDBP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSuccess\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eFailure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eP value*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eSuccess\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003eFailure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eP value*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePre induction\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e123.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e132\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e9.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.910\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e72.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e1.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.078\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePost-induction\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e110.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e5.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e113.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.782\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e71.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e8.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e77.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e14.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.299\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e1 hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e124.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e127.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e16.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.428\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e80.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.970\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e2 hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e124.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e117\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e77.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e8.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.378\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e3hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e124.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e11.31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.883\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6.69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e84.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e7.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.325\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e4hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e127.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e116.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e9.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.578\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e78.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.604\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e5hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e124.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e114\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.054\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e79.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e82.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e6.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.467\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003e6hour\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e122.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e117.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.138\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e81.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e5.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e80.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e4.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.868\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePost-op\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e125.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e164\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e6.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e77.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e3.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAt Dissection\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e122.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e131.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e80.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e6.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e77.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.486\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAt Anastomosis\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e121.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e168.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e76.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"11\"\u003e*Independent T-test\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of Blood transfusion among successful and failed cases\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBlood Transfusion\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSuccessful\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eFailure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP \u0026ndash; value*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003en\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e%\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003en\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e%\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.223\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNo\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e66.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e66.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eYes\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Chi \u0026ndash; square test\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eNo statistically significant difference was noted in the success and failure group, if blood transfusion was given or not given after the flap reconstruction. (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eNo statistically significant differences between Success and Failure groups for pH, CO₂, and HCO₃, indicating similar respiratory and metabolic conditions. Lactate levels tend to be lower in the Failure group pre- and post-operatively, but this is not statistically significant. The Failure group showed a slight post-op pH increase (alkalosis), which might suggest a physiological response to stress or interventions like hyperventilation. (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of ABG values among successful and failed attempt cases\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eABG values\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSuccess\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eFailure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eP value*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMean\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003ePre-operative values\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003epH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.332\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCO2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e38.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.419\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHCO3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.502\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLactates\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.774\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePost-operative values\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003epH\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCO2\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e39.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e40.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHCO3\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLactates\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Independent T - test\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDuring microvascular free flap reconstruction, optimal blood pressure control during the perioperative period is crucial to minimise patient morbidity and maximize free flap survival.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e However, during induction and intraoperatively period, the general anaesthetic agents tend to induce systemic hypotension which can result in hypoperfusion of critical organs and the flap itself. The overall success rate of free flap noted in our study was 90%, which was similar to the reported rate in most previously published studies.\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe effects of different anaesthetic agents on the microvascular parameter of the free flap and its fluid distribution remain unclear.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e Studies have shown that the use of sevoflurane compared with intravenous anaesthetics such as propofol has shown beneficial effects on microcirculation, reducing the plasma leakage into interstitial space and decreasing oedema. There is evidence showing the beneficial effects of inhalational agents on different mechanisms of ischaemia\u0026ndash;reperfusion injury.\u003csup\u003e\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e In this study, all the patients were maintained with inhalational anaesthesia isoflurane with MAC of 1 and intermittent bolus dose of 20mg intravenous propofol to maintain the systolic blood pressure less than 130mmHg.\u003c/p\u003e \u003cp\u003eIntraoperative hypotension may be dealt with by reducing the dosage of anaesthetic agents or increasing the volume of intravenous fluids. Reducing the dosage of anaesthetic agents is not feasible as a certain depth of anaesthesia needs to be maintained intraoperatively. Overzealous use of intravenous fluids may cause pulmonary oedema with resultant cardiopulmonary decompensation. Intravenous fluid infusion is associated with flap oedema and surrounding tissue oedema, which progressively impair flap microcirculation by mechanical compression of the microvasculature or pedicle vessels.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e The free flap lacks lymphatic drainage and denervation of the free flap decreases interstitial fluid reabsorption, causing the free flap more prone to graft oedema, contributing to adverse flap outcomes.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Perioperative overzealous use of fluids is also associated with increased anastomotic thrombosis, flap complications and medical complications.\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe use of vasopressor may be necessary in certain situations to maintain an acceptable mean blood pressure. Spectral analysis of laser Doppler blood flow signals in free flap reconstruction patients has demonstrated that the use of norepinephrine, and control of blood flow shifted towards low-frequency vasomotion where blood flow depended mostly on an average blood pressure. Hence, the use of noradrenaline could be considered the most suitable agent following free flap reconstruction.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn this study, the success group had stable blood pressure throughout the surgery, but on the contrary, the failure group had a drop in blood pressure post-induction. The blood pressure in the failure group was increased by giving intraoperative fluids and starting the patient on noradrenaline inotropic agents. There were 3 cases in the success group, where the use of noradrenaline inotropic agents to increase blood pressure had no adverse flap outcome.\u003c/p\u003e \u003cp\u003eThe use of noradrenaline is noted to increase the free flap skin blood flow more when compared to other vasopressor agents, making it the most suitable inotropic agent during hypotension in patients undergoing free flap reconstruction. The noradrenaline acts on both alpha \u0026ndash; 1 and alpha \u0026ndash; 2 adrenergic receptors to cause vasoconstriction and thereby increase blood pressure.\u003c/p\u003e \u003cp\u003eIn a retrospective review by Kelly \u003cem\u003eet al\u003c/em\u003e., on the impact of intraoperative vasopressor use in free tissue transfer during the head, neck, and extremity reconstruction, it was found that the frequency of vasopressor use was 53.2% with no significant difference in flap outcome in patients who received vasopressors and those who did not.\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Another randomized controlled trial in patients undergoing ablative and reconstructive headandneck surgery with microvascular flap also showed noradrenaline to be safe and effective for use in the postoperative period when used to maintain MAP between 80 and 90 mmHg.\u003csup\u003e17\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe common cause of flap failure seen in the literature is multifactorial such as arterial (arterial thrombosis, vasospasm), venous (venous thrombosis, vasospasm, mechanical compression), flap oedema (overzealous use of fluids, hemodilution), generalised vasoconstriction (hypothermia, pain, respiratory alkalosis), hypotension (hypovolemia, myocardial depressants) and prolonged ischemia of the flap.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Venous thrombosis is noted to be the most common cause of flap failure followed by arterial obstruction.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis study emphasizes the critical role of perioperative hemodynamic stability in optimizing free flap survival during microvascular free flap reconstruction. A stable hemodynamic profile was noted in the success group, whereas the failure group exhibited intraoperative hypotension that required intravenous fluids administration and use of noradrenaline inotropic support.\u003c/p\u003e \u003cp\u003eDespite concerns regarding vasopressor use, our findings, along with evidence from previous studies, indicate that noradrenaline is a safe and effective agent for maintaining adequate mean arterial pressure (MAP) without compromising flap viability. Inhalational anesthesia, particularly sevoflurane, appears to offer beneficial effects on microcirculation, potentially reducing flap edema and ischemia\u0026ndash;reperfusion injury. However, excessive intravenous fluid administration should be avoided due to its association with flap edema and increased risk of anastomotic thrombosis.\u003c/p\u003e \u003cp\u003eFlap failure is multifactorial commonly attributed to venous thrombosis, arterial thrombosis, vasospasm, and mechanical compression a comprehensive approach involving meticulous intraoperative monitoring, judicious fluid management, and appropriate vasopressor use is essential for improving free flap survival rates. Future studies with larger sample sizes and randomized controlled trials are warranted to further refine perioperative management strategies and optimize surgical outcomes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cul type=\"disc\"\u003e\n \u003cli\u003eEthics approval and consent to participate \u0026ndash; obtained by yenepoya ethical committee\u003c/li\u003e\n \u003cli\u003eConsent for publication \u0026ndash; obtained from the participants\u003c/li\u003e\n \u003cli\u003eAvailability of data and materials \u0026ndash; The datasets generated and/or analysed during the current study are not publicly available due to the nondisclosure of personal data of participants in the public domain but are available from the corresponding author on reasonable request.\u003c/li\u003e\n \u003cli\u003eCompeting interests \u0026ndash; I declare that there are no competing interests\u003c/li\u003e\n \u003cli\u003eFunding \u0026ndash; not applicable\u003c/li\u003e\n \u003cli\u003eAuthors\u0026apos; contributions \u0026ndash;\u003c/li\u003e\n\u003c/ul\u003e\n\u003col\u003e\n \u003cli\u003eMSR - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient\u003c/li\u003e\n \u003cli\u003eSGR - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient\u003c/li\u003e\n \u003cli\u003eIA - Analysis and interpretation of patient data regarding the anaesthesia in flap reconstruction patient\u003c/li\u003e\n \u003cli\u003eDS - Surgeon performing the operation on the patient\u003c/li\u003e\n \u003cli\u003eAR - Surgeon performing the operation on the patient\u003c/li\u003e\n\u003c/ol\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eAcknowledgements \u0026ndash; Not applicable\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMin, K.; Hong, J.P.; Suh, H.P. Risk Factors for Partial Flap Loss in a Free Flap: A 12-Year Retrospective Study of Anterolateral Thigh Free Flaps in 303 Lower Extremity Cases. Plast. Reconstr. Surg. \u003cstrong\u003e2022\u003c/strong\u003e, 150, 1071e\u0026ndash;1081e. [CrossRef] [PubMed]\u003c/li\u003e\n\u003cli\u003eWei, F.C.; Lin Tay, S.K.; Al Deek, N.F. Principles and techniques of microvascular surgery. Plast. Surg. \u003cstrong\u003e2024\u003c/strong\u003e, 25, 414\u0026ndash;415.\u003c/li\u003e\n\u003cli\u003eJayaram K, Rao P, Gurajala I, Ramachandran G. Evaluation of the Effect of Regional Anaesthesia on Microvascular Free Flaps. Turk J Anaesthesiol Reanim 2018; 46(6): 441-6.\u003c/li\u003e\n\u003cli\u003eChen C, Nguyen MD, Bar-Meir E, et al. Effects of vasopressor administration on the outcomes of microsurgical breast reconstruction. Ann Plast Surg 2010;65(01):28\u0026ndash;31\u003c/li\u003e\n\u003cli\u003eHaughey BH, Wilson E, Kluwe L, et al. Free flap reconstruction of the head and neck: analysis of 241 cases. Otolaryngol Head Neck Surg 2001;125(01):10\u0026ndash;17\u003c/li\u003e\n\u003cli\u003eSigurdsson GH, Thomson D. Anaesthesia and microvascular surgery: Clinical practice and research. Eur J Anaesthesiol 1995; 12: 101-22.\u003c/li\u003e\n\u003cli\u003eHahn RG. Microvascular changes and anaesthesia. Acta Anaesthesiol Scand 2002; 46: 479-80. [CrossRef]\u003c/li\u003e\n\u003cli\u003eBruegger D, Bauer A, Finsterer U, Bernasconi P, Kreimeier U, Christ F. Microvascular changes during anaesthesia: Sevoflurane compared with propofol. Acta Anaesthesiol Scand 2002; 46: 481-7. [CrossRef]\u003c/li\u003e\n\u003cli\u003ePreckel B, Schlack W, Comfere T, Obal D, Barthel H, Thamer V. Effects of enflurane, isoflurane, sevoflurane, and desflurane on reperfusion injury after regional myocardial ischaemia in the rabbit heart in vivo. Br J Anaesth 1998; 81: 905-12. [CrossRef]\u003c/li\u003e\n\u003cli\u003ePiriou V, Chiari P, Lhuillier F, Bastien O, Loufoua J, Raisky O, et al. Pharmacological preconditioning: Comparison of desflurane, sevoflurane, isoflurane and halothane in rabbit myocardium. Br J Anaesth 2002; 89: 486-91. [CrossRef]\u003c/li\u003e\n\u003cli\u003eHaughey BH, Wilson E, Kluwe L, et al. Free flap reconstruction of the head and neck: analysis of 241 cases. Otolaryngol Head Neck Surg 2001;125(01):10\u0026ndash;17\u003c/li\u003e\n\u003cli\u003eWei FC, Mardini S. Flaps and Reconstructive Surgery. 1st ed. Philadelphia, PA: Saunders (Imprint), Elsevier; 2009\u003c/li\u003e\n\u003cli\u003eSigurdsson GH. Perioperative fluid management in microvascular surgery. J Reconstr Microsurg 1995;11(01):57\u0026ndash;65 \u003c/li\u003e\n\u003cli\u003eBooi DI. Perioperative fluid overload increases anastomosis thrombosis in the free TRAM flap used for breast reconstruction. Eur J Plast Surg 2011;34(02):81\u0026ndash;86\u003c/li\u003e\n\u003cli\u003eEley KA, Young JD, Watt‑Smith SR. Power spectral analysis of the effects of epinephrine, norepinephrine, dobutamine and dopexamine on microcirculation following free tissue transfer. Microsurgery 2013;33:275‑81\u003c/li\u003e\n\u003cli\u003eKelly DA, Reynolds M, Crantford C, Pestana IA. Impact of intraoperative vasopressor use in free tissue transfer for head, neck, and extremity reconstruction. Ann Plast Surg 2014;72:S135‑8.\u003c/li\u003e\n\u003cli\u003eRaittinen L, K\u0026auml;\u0026auml;ri\u0026auml;inen MT, Lopez JF, Pukander J, Laranne J. The effect of norepinephrine and dopamine on radial forearm flap partial tissue oxygen pressure and microdialysate metabolite measurements: A randomized controlled trial. Plast Reconstr Surg 2016;137:1016e‑23e.\u003c/li\u003e\n\u003cli\u003eAdams J, Charlton P. Anesthesia for microvascular free tissue transfer. Br J Anaesth (CEPD Reviews) 2003;3:33‑7.\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":"Microvascular flap reconstruction, Flap anaesthesia, reconstructive surgery, general anaesthesia","lastPublishedDoi":"10.21203/rs.3.rs-6246819/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6246819/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eMicrovascular free flap reconstruction is a complex surgical procedure used to repair tissue defects from trauma, oncology, or chronic wounds. Despite advancements in surgical techniques, flap failure due to hypoperfusion and necrosis remains a challenge. Hemodynamic stability during the perioperative period is a key determinant of flap survival, but the influence of anaesthetic management on flap outcomes is not well studied.\u003c/p\u003e\u003ch2\u003eObjective\u003c/h2\u003e \u003cp\u003eTo analyse the impact of intraoperative hemodynamic stability and anaesthetic factors on the success of microvascular free flap reconstruction.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eA retrospective study was conducted in a tertiary hospital in India from March 2023 to April 2024. A total of 30 patients (aged 25\u0026ndash;75 years) undergoing elective microvascular free flap reconstruction under general anaesthesia were included. Hemodynamic parameters (blood pressure, heart rate), arterial blood gas (ABG) values, and flap outcomes were recorded preoperatively, intraoperatively, and postoperatively. Statistical analysis was performed using SPSS version 23.0, with significance set at p\u0026thinsp;\u0026le;\u0026thinsp;0.05.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe overall success rate of free flap reconstruction was 90%. No significant differences in intraoperative systolic and diastolic blood pressure were observed between the success and failure groups, except at the time of anastomosis (SBP: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, DBP: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and postoperatively (SBP: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, DBP: p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Use of noradrenaline to manage intraoperative hypotension did not negatively affect flap survival. Excessive fluid administration was associated with flap edema and increased failure risk.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003ePerioperative hemodynamic stability is critical for successful microvascular free flap outcomes. Noradrenaline is a safe and effective agent for maintaining blood pressure without compromising flap viability. Careful fluid management and stable hemodynamic control are essential to optimize flap survival rates. Further studies with larger sample sizes are warranted to validate these findings.\u003c/p\u003e","manuscriptTitle":"Correlation Between Perioperative Hemodynamics and Flap outcome in Microvascular Flap Reconstruction – A Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-04 09:52:33","doi":"10.21203/rs.3.rs-6246819/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":"b311e76e-5c23-4f3c-989a-8b52ce46b57a","owner":[],"postedDate":"April 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-05-20T17:23:26+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-04 09:52:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6246819","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6246819","identity":"rs-6246819","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}