Comparison of two warming interventions in surgical patients with mild and moderate hypothermia


Dr Maree Johnson, Research Professor, Centre for Applied Nursing Research, Locked Bag 7103, Liverpool BC, NSW 1871, Australia. Email:


Two interventions: a forced warm-air device (Bair-Hugger series 500, Augustine Medical Inc., Eden Prairie, MN, USA), group 1; and a standardized approach to the use of warmed blankets (group 2) are compared with the aim of enhancing thermoregulation in surgical patients with mild and moderate hypothermia in the immediate recovery period. One hundred and twenty patients in a post-anaesthetic care unit were systematically allocated to group 1 or group 2 so each group consisted of 110 participants. No significant differences were found between the groups in gender, age, time in surgery, use of warmed intravenous fluids or muscle relaxants, or type of surgery. After exclusion of orthopaedic patients, significant differences in the mean rewarming rates were found, with more rapid rewarming occurring within group 1 (the group rewarmed with a forced warm-air device, t = 2.15, df = 92, P = 0.03) compared with group 2. No significant differences were found in the mean rewarming time, or heat gain between groups, and subsequent power estimates were less than 0.80. This study supports improved rewarming rates in select surgical patients (with mild or moderate hypothermia) using the Bair-HuggerTM compared with a standardized blanket rewarming intervention and identifies the need for patient comfort and cost-benefit analysis to be considered in future studies.