Forced air-warming blanket versus pethidine for the prevention of shivering during and after caesarean section

Abstract

Background Spinal anaesthesia significantly impairs thermoregulation by inhibiting vasomotor and shivering responses and by redistributing heat from the core of body to peripheral tissues. Core hypothermia may be associated with a number of adverse outcomes in pregnant women, including shivering, wound infection, coagulopathy, increased blood loss and transfusion requirements. Several pharmacological and mechanical methods have been used in an attempt to maintain normothermia and prevent intra-anaesthetic and postanaesthetic shivering. Therefore, the aim of the present study was to compare the efficacy of prophylactic use of forced air-warming blanket with pethidine for the prevention of shivering during and after spinal anaesthesia in elective caesarean section. Patients and methods The present study included 96 pregnant women with ASA I and II, admitted to Al Shatby Maternity Hospital. Patients were randomly assigned into three equal groups of 32 patients each. Group I patients were covered with forced air-warming blanket over the upper limbs and chest, group II patients received a single bolus of 0.5 mg/kg pethidine intravenously and group III patients did not receive anything, and they were regarded as control. Results Heart rate and mean arterial blood pressure decreased significantly in all the three studied groups after spinal anaesthesia. The decrease in the mean arterial blood pressure required ephedrine boluses, which ranged between 0 and 4 boluses, with no significance between the three studied groups. The core body temperature decreased significantly 15 min after spinal anaesthesia and thereafter in all patients of the three studied groups. However, the decrease in core temperature was significantly more in groups II and III. The shivering score increased significantly 10 min after spinal anaesthesia and thereafter intraoperatively. The shivering scores were significantly lower in groups I and II when compared with group III. There was a negative correlation between core body temperature and shivering scores in all the three studied groups. The mean core body temperature for shivering patients was significantly less in group II patients compared with groups I and III patients. The three groups were matched as regard to APGAR score at 1 and 5 min. No significant changes were observed as regard to hypotension, nausea, vomiting and feeling cold extremities. Conclusion Forced air-warming blanket decreased the shivering incidence by preserving core body temperature, whereas pethidine can prevent and treat shivering.