Evaluating Shivering and Hypothermia After Removing Forced-Air Heating From Short-Duration Surgery

Single-use forced-air heating blankets can prevent intraoperative hypothermia, but their use carries environmental and economic costs. Whether omitting heating blankets for short-duration surgical procedures affects patient outcomes remains unclear.

To evaluate changes in shivering and hypothermia of removing forced-air heating from short-duration surgical procedures.

Pragmatic, prospective before-and-after cohort study.

Surgical ward in a secondary university hospital in 2023.

Adults undergoing orthopaedic or abdominal procedures below 90 min.

Comparing active forced-air heating to no heating after a guideline change.

Co-primary outcomes were intraoperative hypothermia (< 35.5°C) and shivering (symptom or need for rescue medication) in the post-anaesthetic care unit. Data were extracted from electronic health records.

We included 1059 and 1106 surgeries in the heating and no-heating group, respectively. Baseline characteristics were similar with mean 48 min surgery duration. Intraoperative hypothermia occurred more frequently in the no-heating group with 5.58% versus 2.73% in the heating group (relative risk, 97.5% confidence interval): 2.04, 1.11-3.95, p = 0.011. Shivering occurred more frequently in the no-heating group with 6.1% versus 4.0% in the heating group (relative risk, 97.5% confidence interval): 1.55, 1.02-2.41, p = 0.021. Preventing one shivering event cost $235 and 62.9 kg CO₂ equivalents. There were no differences in anaesthesia emergence time or need for/length of post-anaesthetic care unit stay.

Omitting forced-air heating significantly increased hypothermia occurrence by 2.85% and shivering by 2.18%, while reducing costs and carbon emissions. This relationship between beneficial patient-related effects and negative climate/economic costs is controversial. The patients' perspective in terms of thermal comfort outcomes should be investigated.

Protocol on Zenodo prior to data analysis.

This retrospective analysis compared cases with shorter surgery times where either active warming or not (simple routine insulating) were compared for risk of intraoperative temperature assessed less than 35.5 or shivering, as well as post anaesthesia unit time. Costs were estimated (for active warming materiel) to prevent a single shivering event.