Prediction of Perioperative Hypothermia and Response to Active Warming in Women Undergoing Scheduled Cesarean Delivery
Abstract Number: F-09
Abstract Type: Original Research
Introduction: Core-to-peripheral redistribution of heat is the major mechanism leading to early perioperative hypothermia after neuraxial anesthesia (1). The study aim was to determine if patient's preoperative skin temperature or skin-to-core temperature gradient predicted temperature decrease and hypothermia in women undergoing cesarean delivery with spinal anesthesia.
Methods: 46 healthy women undergoing scheduled cesarean delivery under spinal anesthesia (10-12.5 mg bupivacaine ± fentanyl) were enrolled in this randomized controlled study. Skin temperature and skin-to-core temperature gradients were measured preoperatively, intraoperatively (every 10 min), and for 1 hour postoperatively (every 15 min). Participants were randomized to receive active warming (warmed intravenous fluid co-load and lower-body forced-air warmer set to high intra-operatively) or no active warming. Outcomes included maximum perioperative core temperature decrease, incidence of shivering and hypothermia (<36oC), meperidine requirements, and thermal comfort scores. Univariate correlations and regression analysis and between-group parametric and non-parametric comparisons as appropriate were applied.
Results: There was no correlation between preoperative skin temperature or skin-to-core temperature gradient and maximum perioperative core temperature decrease (Figure 1). The mean ± SD preoperative skin-to-core temperature gradients of women who developed hypothermia compared to those who did not was 4.5 ± 0.9 and 4.7 ± 0.7 respectively (p=0.507). There was no significant correlation between preoperative skin temperature (R=0.195, p=0.216) or skin-to-core temperature gradient (R=-0.118, p=0.456) and intraoperative thermal comfort scores. Mean ± SD preoperative skin temperature of women who shivered and did not shiver intraoperatively was 32.7 ± 0.6 and 32.2 ± 0.8 respectively (p=0.041). Preoperative skin temperature and skin-to-core temperature gradients did not predict meperidine use or response to active warming.
Conclusion: Preoperative skin temperature and skin-to-core temperature gradient do not predict the development of maternal hypothermia or shivering, thermal comfort, or response to active warming. This is the first study trying to identify predictors of perioperative hypothermia and shivering in women undergoing cesarean delivery, with the aim of facilitating targeted application of active warming.
Anesthesiology 1995; 83(5): 961-7