Effect of Intravenous Fluid and Local Anaesthetic Warming on Core Temperature Following Subarachnoid Block for Caesarean Section

Background: Hypothermia and shivering often complicate spinal anaesthesia for Caesarean section, and has necessitated the search for an effective and affordable warming method for parturient. 
Aim: To compare the effects of intravenous fluid and local anaesthetic warming on core temperature during Caesarean section under spinal anaesthesia. 
Methods: One hundred and sixteen consenting parturients aged 18 to 40 years with ASA physical status class II scheduled for elective Caesarean section were recruited into the study. Patients were randomly allocated into groups I, II, III and IV. All the patients were preloaded with 15 ml/kg of normal saline over 15 minutes before institution of subarachnoid block in the sitting position. Warm intravenous fluid and warm intrathecal bupivacaine, warm intravenous fluid and intrathecal bupivacaine at room temperature, intravenous fluid at room temperature and warm intrathecal bupivacaine, and both intravenous fluid and intrathecal bupivacaine at room temperature were administered to patients in groups I, II, III, IV respectively. Data collected included core temperature (tympanic membrane) using a thermoscan, shivering using the 5-point scale of Wrench. Neonatal rectal temperature was measured and adverse effects observed on the parturients recorded. Monitoring of core temperature was continued in the post anaesthesia care unit until full recovery and discharge. 
Results: All the 116 patients completed the study. While core temperature change was highest (-0.43 ± 0.30) in group IV and lowest in group I (-0.07 ± 0.58), it was -0.16 ± 0.09 in group II and -0.24 ± 0.16 in group III, p=0.001. Hypothermia was observed in group IV, with an incidence of 10.3%. Group IV also had the highest incidence of shivering (31%), followed by group III (10.3%) and group II (6.9%) while group I had zero incidence of shivering. The neonatal temperature was similar across the study groups. Vomiting was recorded in one patient in groups III (3.4%) and IV (3.4%). Bradycardia occurred in two patients in groups III (6.9%) and one patient in group IV (3.4%). Hypotension was observed in two patients in group III (6.9%) and one patient in group IV (3.4%). 
Conclusion: Warming of intravenous fluid and intrathecal bupivacaine reduced maternal temperature change during Caesarean section under subarachnoid block, but there was no significant difference in the incidence of shivering between the combination of warm intravenous fluid and warm intrathecal bupivacaine, and warm intravenous fluid alone.