Influence of Non-Compressible Versus Compressible Underbody Forced-Air Warming Systems on Core Temperature in Off-Pump Cardiac Surgery.

OBJECTIVE

To compare intraoperative core temperature maintenance using non-compressible versus compressible underbody forced-air warming systems in off-pump cardiac surgery.

DESIGN

Retrospective single-center cohort study with a before-after comparison.

SETTING

A tertiary university hospital cardiac operating rooms and intensive care unit.

PARTICIPANTS

100 adults undergoing off-pump coronary revascularization (49 treated during the compressible forced-air period; 51 during the non-compressible period) between May 2021 and July 2023.

INTERVENTIONS: Intraoperative underbody warming with either a compressible forced-air blanket (setpoint 43°C) or a non-compressible forced-air blanket (setpoint 43°C). The same underbody device was used for prewarming (15-20 minutes) and intraoperative warming. Intravenous fluids were warmed in all patients; no additional upper-body active warming was used.

MEASUREMENTS AND MAIN

RESULTS

Core body temperature was continuously measured via a bladder thermistor from the induction of anesthesia until intensive care unit transfer. The primary outcome was the maximum negative deviation from baseline (ΔTneg). To address baseline imbalances, propensity score overlap weighting was applied. ΔTneg did not differ significantly between groups: median [IQR] non-compressible -0.40°C [-0.75; 0.00] v compressible -0.50°C [-1.10; -0.10]; Hodges-Lehmann median difference -0.10°C (95% CI: -0.40 to 0.10; p = 0.23). In propensity score-weighted multivariable regression, only baseline temperature was independently associated with ΔTneg (β = -0.36, p = 0.002); the warming device had no significant effect (β = -0.07, p = 0.62).

CONCLUSIONS

In off-pump cardiac surgery, non-compressible and compressible underbody warming systems provided comparable intraoperative thermal performance.