Effects of combined warmed preoperative forced-air and warmed perioperative intravenous fluids on maternal temperature during cesarean section: a prospective, randomized, controlled clinical trial

Abstract

Background: Preventing the frequent perioperative hypothermia incidents that occur during elective caesarean deliveries would be beneficial. This trial aimed at evaluating the effect of preoperative forced-air warming alongside perioperative intravenous fluid warming in women undergoing cesarean sections under spinal anesthesia.

Methods: We randomly allocated 135 women undergoing elective cesarean deliveries to either the intervention group (preoperative forced-air and intravenous fluid warming, n = 69) or the control group (no active warming, n = 66). The primary outcome measure was the core temperature change between groups from baseline to the end of the surgical procedure. Secondary outcomes included thermal comfort scores, the incidences of shivering and hypothermia (< 36 °C), the core temperature on arrival at the post-anesthesia care unit, neonatal axillary temperature at birth, and Apgar scores.

Results: Two-way repeated measures ANOVA revealed significantly different core temperature changes (from the pre-spinal temperature to that at the end of the procedure) between groups (F = 13.022, P < 0.001). The thermal comfort scores were also higher in the intervention group than in the control group (F = 9.847, P = 0.002). The overall incidence of perioperative hypothermia was significantly lower in the intervention group than in the control group (20.6% vs. 51.6%, P < 0.0001).

Conclusions: Warming preoperative forced-air and perioperative intravenous fluids may prevent maternal hypothermia, reduce maternal shivering, and improve maternal thermal comfort for patients undergoing cesarean sections under spinal anesthesia.

Trial registration: The study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR1800019117) on October26, 2018.

Keywords: Cesarean section; Spinal anesthesia; Warming.

Fig. 1

Flow diagram outlining the enrollment and randomization study procedures

Fig. 2

Core tympanic temperatures during the procedure. Compared with control group, the patients in intervention group experienced higher perioperative mean temperatures during the procedure (T₁-T₃, P < 0.001, T₄-T₇, P < 0.05). Timepoints: T₀ = baseline, T₁ = pre-spinal, T₂ = post-spinal, T₃ = after 15 min in the OR, T₄ = after 30 min in the OR, T₅ = surgery end, T₆ = PACU arrival, T₇ = after 15 min in the PACU, T₈ = after 30 min in the PACU. OR: operating room; PACU: post-anesthesia care unit. *P < 0.001,^#P < 0.05 refer to statistically significant differences between the intervention and the control groups. ⁺P < 0.001_,⁻P < 0.05 refer to comparisons with the baseline (T₀)

Fig. 3

Maternal comfort scores during the procedure. The maternal thermal comfort scores differed significantly between two groups from the T₂ to T₆ timepoints (all P < 0.05 or P < 0.001). Timepoints: T₀ = baseline, T₁ = pre-spinal, T₂ = post-spinal, T₃ = after 15 min in the OR, T₄ = after 30 min in the OR, T₅ = surgery end, T₆ = PACU arrival, T₇ = after 15 min in the PACU,T₈ = after 30 min in the PACU. We measured thermal comfort scores using a verbal numerical scale in which 0 was defined as completely unsatisfied with their “thermal comfort” and 100 as completely satisfied. *P < 0.001,^#P < 0.05 refer to statistically significant difference between the intervention and the control groups. ⁺P < 0.001_,⁻P < 0.05 refer to comparisons with baseline (T₀)