Intrathecal Morphine–Related Perioperative Hypothermia in Women Undergoing Cesarean Delivery: A Retrospective Case-Control Study

Abstract

Rates of inadvertent perioperative hypothermia among women undergoing spinal anesthesia for cesarean delivery are reported to be high. Intrathecal morphine has been noted to have a potentially potent effect on thermoregulation. This retrospective case-control study sought to investigate the incidence of perioperative hypothermia in women undergoing cesarean delivery with and without intrathecal morphine and to describe any clinical factors associated with the condition, the identification of which would provide direction for nursing priorities in the care of the condition. A retrospective case-controlled study design was used. The charts of 358 women who had undergone emergency or elective cesarean delivery under spinal anesthesia were reviewed: 179 having received intrathecal morphine and 179 having received spinal anesthesia without intrathecal morphine (control group). SPSS (IBM, Armonk, New York), version 22, was used for data analysis, including logistic regression to predict the outcome of hypothermia across the study population. There was no significant difference (P=.62; 95% confidence interval, -0.09 to 0.15) in mean postoperative temperature for the morphine group (mean postanesthesia care unit arrival temperature, 35.91°C; standard deviation, 0.59) and the no morphine group (mean postanesthesia care unit arrival temperature, 35.88°C; standard deviation, 0.52). However, within groups, the temperature decline preoperatively to postoperatively was statistically (and clinically) significant. The results refute the suggestion that intrathecal morphine contributes to greater core temperature decline in this population; however, it does confirm that perioperative hypothermia is a prevalent concern for women undergoing cesarean delivery and that pre-emptive measures should be routinely considered by health care providers.