What is the predictor of the intraoperative body temperature in abdominal surgery?

Inadvertent hypothermia is a relatively common intraoperative complication. Few studies have investigated predictors of body temperature change or the effect of the blanket type used with a forced-air warming device during the intraoperative period. We investigated the predictive factors of intraoperative body temperature change in scheduled abdominal surgery.

We retrospectively reviewed the data from 2574 consecutive adult patients who underwent scheduled abdominal surgery in the supine position. Temperature data were collected from anesthesia records. Multiple regression analysis was performed at 60, 120, and 180 min after the surgical incision to identify the factors influencing body temperature change. We conducted nonlinear regression analysis using the equation ΔT = α (e^-γt-1) + βt, where ΔT represented the change in intraoperative core temperature (°C), t represented the surgical duration (minutes), and α, β, and γ were constants.

The intraoperative core temperature change was explained by the equation ΔT = 0.59 (e^- 0.018t - 1) + 0.0043t. Younger age, higher body mass index (BMI), male sex, laparoscopic surgery, and use of an underbody blanket were associated with increased core temperature at 1 or 2 h after surgical incision. Male sex and an underbody blanket remained strong predictive variables even 3 h after surgical incision, whereas BMI had little explanatory power at this timepoint. The difference in the heating effect of an underbody versus an overbody blanket was 0.0012 °C per minute.

The blanket type of the forced-air warmer, age, sex, laparoscopic surgery, and BMI are predictors of intraoperative core temperature change.