Phenylephrine Attenuates Intra-Operative Hypothermia during Spinal Anaesthesia

Abstract

Inadvertent hypothermia is common during spinal anaesthesia. This study was based on the hypothesis that phenylephrine might attenuate core hypothermia by inhibiting core-to-peripheral redistribution of body heat during spinal anaesthesia. In this prospective randomized study, 20 patients who underwent elective orthopaedic surgery under spinal anaesthesia were randomly assigned to receive either normal saline (control group) or continuously-infused phenylephrine 0.5 μg/kg per min (phenylephrine group). Core temperature, heart rate (HR) and mean arterial pressure (MAP) were monitored. Mean ± SE core temperature at the end of surgery was significantly higher in the phenylephrine-treated group compared with the control group (35.9 ± 0.1 °C versus 35.0 ± 0.1 °C, respectively), although there was no significant difference in baseline core temperature (both groups 36.3 ± 0.1 °C). Mean HR and MAP were not significantly different between the two groups. In conclusion, continuously-infused phenylephrine attenuated core hypothermia during spinal anaesthesia without any haemodynamic complications.