Division of Hand, Plastic and Aesthetic Surgery, University Hospital, LMU Munich, Munich, Germany.
Department of Plastic, Reconstructive, Hand and Burn Surgery, Bogenhausen Academic Teaching Hospital, Munich, Germany.
J Reconstr Microsurg. 2021 Feb;37(2):174-180. doi: 10.1055/s-0040-1715880. Epub 2020 Aug 30.
Patients requiring microsurgical defect reconstruction are highly susceptible to intraoperative hypothermia, given oftentimes long operative times and exposure of large skin surface areas. While the impact of hypothermia has been extensively studied across various surgical fields, its role in the setting of microsurgical free flap reconstruction remains elusive. This study evaluates the effects of hypothermia on outcomes of free flap reconstructions.
Within 7 years, 602 patients underwent 668 microvascular free flap reconstructions. The cases were divided into two groups regarding the minimal core body temperature during free flap surgery: hypothermia (HT; < 36.0°C) versus normothermia (NT; ≥36.0°C). The data were retrospectively screened for patients' demographics, perioperative details, flap survival, surgical complications, and outcomes.
Our data revealed no significant difference with regard to the rate of major and minor surgical complications, or the rate of revision surgery between both groups ( > 0.05). However, patients in the HT group showed significantly higher rates of total flap loss (6.6% [HT] vs. 3.0% [NT], < 0.05) and arterial thrombosis (4.6% [HT] vs. 1.9% [NT], < 0.05). This translated into a significantly longer hospitalization of patients with reduced core body temperature (HT: mean 16.8 days vs. NT: mean 15.1 days; < 0.05).
Hypothermia increases the risk for arterial thrombosis and total flap loss. While free flap transfer is feasible also in hypothermic patients, surgeons' awareness of core body temperature should increase. Taken together, we suggest that the mean intraoperative minimum temperature should range between 36 and 36.5°C during free flap surgery as a pragmatic guideline.
由于手术时间长且暴露的皮肤面积大，需要显微外科缺陷重建的患者极易发生术中低体温。尽管低体温在各个外科领域的影响已得到广泛研究，但在显微外科游离皮瓣重建中其作用仍不清楚。本研究评估了低体温对游离皮瓣重建结果的影响。
在 7 年内，602 例患者接受了 668 例显微血管游离皮瓣重建。根据游离皮瓣手术过程中的最低核心体温，将病例分为两组：低体温组（HT；<36.0°C）和正常体温组（NT；≥36.0°C）。回顾性筛选患者的人口统计学、围手术期细节、皮瓣存活、手术并发症和结果数据。
我们的数据显示，两组间主要和次要手术并发症的发生率或修复手术的发生率均无显著差异（>0.05）。然而，HT 组患者的总皮瓣失活率（6.6%[HT]比 3.0%[NT]，<0.05）和动脉血栓形成率（4.6%[HT]比 1.9%[NT]，<0.05）明显更高。这导致体温降低的患者住院时间明显延长（HT：平均 16.8 天，NT：平均 15.1 天；<0.05）。
低体温增加了动脉血栓形成和总皮瓣失活的风险。虽然在低体温患者中也可以进行游离皮瓣转移，但外科医生应提高对核心体温的认识。总之，我们建议在游离皮瓣手术中，术中最低平均温度应在 36 至 36.5°C 之间，这是一个实用的指导原则。
