The effects of a resistive warming mattress during caesarean section: a randomised, controlled trial

•There is a paucity of research into inadvertent perioperative hypothermia in pregnancy.•We investigated the use of an electric warming mattress during caesarean section.•A mattress has advantages for mother, baby and theatre staff over warm air blankets.•Mattress use was associated with a significant reduction in incidence of hypothermia.•Mattress use was associated with a significant attenuation in postoperative haemoglobin drop.

BackgroundThe adverse effects of inadvertent perioperative hypothermia in the surgical population are well established. The aim of this study was to investigate whether a resistive warming mattress would reduce the incidence of inadvertent perioperative hypothermia in patients undergoing elective caesarean section.MethodsA total of 116 pregnant women booked for elective caesarean section were randomised to either intraoperative warming with a mattress or control. The primary outcome was the incidence of inadvertent perioperative hypothermia, defined as a temperature <36.0°C on admission to the recovery room. Shivering in the perioperative period, severity of shivering and the need for treatment, total blood loss, fall in haemoglobin, incidence of blood transfusion, immediate health of baby, and length of hospital stay were also recorded.ResultsThe incidence of inadvertent perioperative hypothermia in the mattress-warmed group was significantly lower than in the control group (5.2% vs. 19.0%, P = 0.043); mean temperatures differed between the two groups, 36.5°C and 36.3°C, respectively (P = 0.046). There was also a significantly lower mean (± SD) haemoglobin change in the mattress-warmed group at −1.1 ± 0.9 g/dL versus −1.6 ± 0.9 g/dL in the control group (P = 0.007). There was no difference in shivering (P = 0.798).ConclusionsA resistive warming mattress reduced the incidence of inadvertent perioperative hypothermia and attenuated the fall in haemoglobin. The use of resistive mattress warming should be considered during caesarean section.