Effect of preoperative warming during cesarean section under spinal anesthesia

Abstract

Background: Postoperative hypothermia and shivering is a frequent event in patients during cesarean section under spinal anesthesia. We assessed the effect of preoperative warming during cesarean delivery under spinal anesthesia for prevention of hypothermia and shivering.

Methods: Forty five patients undergoing elective cesarean section were randomly assigned to three groups. Group F received warmed intravenous fluid (40℃). Group A patients were actively warmed by forced air-warming. Group C was the control group. Forced air-warming and warmed fluid was maintained for the 15 min preceding spinal anesthesia. Core temperature (tympanic membrane) and the skin temperature of arm and thigh were measured and shivering was graded simultaneously.

Results: The core temperature at 45 min decreased less in Groups F and A than Group C (-0.5℃ ± 0.3℃ vs -0.6℃ ± 0.4℃ vs -0.9℃ ± 0.4℃, respectively; P = 0.004). The arm temperature at 15 min and 30 min exhibited a greater increase in Group A than Group F and Group C (P = 0.001 and P = 0.012, respectively). Leg temperature increased similarly among the three groups. The incidence of shivering was significantly less in Group A and Group F than Group C (20%, 13.3%, and 53.3%, respectively; P = 0.035).

Conclusions: Preoperative forced air-warming and warmed fluid prevents hypothermia and shivering in patients undergoing elective cesarean delivery with spinal anesthesia.

Keywords: Cesarean section; Shivering; Spinal anesthesia; Warming.

Fig. 1

Changes in core temperature after prewarming (t = 0 min) and spinal anesthesia (t = 15 min). Data are expressed as mean. The value after 45 min significantly decreased less in Group F and Group A than Group. Group A: forced-air prewarming group, Group C: control group, Group F: intravenous warmed fluids group. ^*P = 0.004.

Fig. 2

Changes in arm temperature after prewarming (t = 0 min) and spinal anesthesia (t = 15 min). Data are expressed as mean. The values at 15 min and 30 min significantly exhibited greater increase in Group A than Group F and Group C. Group A: forced-air prewarming group, Group C: control group, Group F: intravenous warmed fluids group. ^*P = 0.001, ^†P = 0.012.

Fig. 3

Changes in leg temperature after prewarming (t = 0 min) and spinal anesthesia (t = 15 min). Data are expressed as mean. There is no significantly difference among the three groups. Group A: forced-air prewarming group, Group C: control group, Group F: intravenous warmed fluids group.

Fig. 4

Patients who experienced each response at any time. The shivering incidence of group A, group F and group C were 3/15 (20%), 2/15 (13.3%) and 8/15 (53.3%). There is significantly difference among the three groups (P = 0.035). Group A: forced-air prewarming group, Group C: control group, Group F: intravenous warmed fluids groups.