Preoperative anterior thigh temperature does not correlate with perioperative temporal hypothermia during cesarean delivery with spinal anesthesia: Secondary analysis of a randomized control trial.

Background: Core-to-peripheral redistribution of heat, secondary to sympathetic-mediated vasodilation, is the major mechanism leading to early perioperative hypothermia after neuraxial anesthesia. The study aim was to determine if preoperative anterior thigh (peripheral lower extremity) temperature predicted perioperative temporal (core) temperature decrease during cesarean delivery with spinal anesthesia.
Methods: Secondary analysis of data derived from a prospective, randomized study of 46 healthy women undergoing scheduled cesarean delivery with spinal anesthesia was performed. Anterior thigh temperature was measured preoperatively prior to spinal anesthesia. The primary outcome was maximum perioperative temporal temperature decrease. Secondary outcomes included incidence of temporal hypothermia (temperature <36°C), shivering, and thermal comfort scores. This study ran concurrently with a previously published trial comparing no active intraoperative warming with active warming.
Results: There was no correlation between preoperative anterior thigh temperature and maximum perioperative temporal temperature decrease (r=-0.049, P=0.751). The mean±standard deviation preoperative anterior thigh temperature of women who developed temporal hypothermia compared to those who did not was 32.4±0.8°C versus 32.4±0.70°C respectively (P=0.995). Preoperative anterior thigh temperature did not correlate with the incidence of shivering (r=0.267, P=0.080) or thermal comfort scores (r=0.233, P=0.129).
Conclusion: Preoperative anterior thigh temperature does not correlate with the degree of perioperative temporal temperature decrease, likelihood of developing hypothermia, shivering, or thermal comfort during cesarean delivery with spinal anesthesia. Although core-to-peripheral redistribution of heat after neuraxial anesthesia is a major mechanism of perioperative heat loss, a lower extremity temperature prediction hypothesis was not confirmed in this population.
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