Abstract
Background 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.
Methods 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.
Results 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
(p > 0.05). However, patients in the HT group showed significantly higher rates of total
flap loss (6.6% [HT] vs. 3.0% [NT], p < 0.05) and arterial thrombosis (4.6% [HT] vs. 1.9% [NT], p < 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; p < 0.05).
Conclusion 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.
Keywords
hypothermia - free flap reconstruction - risk constellation - temperature - outcome
