Active warming during cesarean delivery

We tested the hypothesis that 15 min of forced-air prewarming, combined with intraoperative warming, prevents hypothermia and shivering in patients undergoing elective cesarean delivery. We simultaneously tested the hypothesis that maintaining maternal normothermia increases newborn temperature, umbilical vein pH, and Apgar scores. Thirty patients undergoing elective cesarean delivery were randomly assigned to forced-air warming or to passive insulation. Warming, started 15 min before the induction of epidural anesthesia. Core temperature was measured at the tympanic membrane, and shivering was graded by visual inspection. Patients evaluated their thermal sensation with visual analog scales. Rectal temperature and umbilical pH were measured in the infants after birth. Results were compared with unpaired, two-tailed Student's t-tests and chi(2) tests. Core temperatures after 2 h of anesthesia were greater in the actively warmed (37.1degreesC +/- 0.4degreesC) than in the unwarmed (36.0degreesC +/- 0.5degreesC; P < 0.01) patients. Shivering was observed in 2 of 15 warmed and 9 of 15 unwarmed mothers (P < 0.05). Babies of warmed mothers had significantly greater core temperatures (37.1degreesC +/- 0.5degreesC vs 36.2degreesC +/- 0.6degreesC) and umbilical vein pH (7.32 +/- 0.07 vs 7.24 +/- 0.07).