A retrospective audit to examine the effectiveness of preoperative warming on hypothermia in spine deformity surgery patients.

Background: Hypothermia (core body temperature <36°C) during surgery has been associated with surgical site infection, a major risk in all spine deformity surgeries. Forced air warming is an important method of intraoperative temperature maintenance in children. In mid-2010, we empirically introduced preoperative warming as a strategy to reduce intraoperative hypothermia.

Objective: We report the prevalence and extent of hypothermia during spine deformity surgeries at our institution and evaluate the effect of the introduction of preoperative warming.

Methods: We performed a retrospective audit of temperature data in children who underwent spine deformity surgeries during two-seven-month periods: November 2011 to June 2012 and 2 years prior to this period (before preoperative warming implementation). Specifically, the following data were obtained: (i) case duration; (ii) first measured temperature; (iii) last measured temperature; (iv) percentage of case spent hypothermic; (v) number of hypothermic episodes per case, and (vi) delay between case start and time of first temperature measured. Data were compared visually and using the Mann-Whitney U-test. Confidence intervals (CI) were obtained using the Hodges-Lehmann estimator.

Results: Preoperative warming reduced the percentage of case duration spent hypothermic by a median of 111.1 min (P < 0.001, 95% CI 77.1-139.9 min). Additionally, it increased the first measured temperature by a median of 0.5°C (P < 0.001, 95% CI 0.3-0.7°C). The last temperature at the end of the case remained unchanged (P = 0.57, 95% CI -0.2-0.1°C).

Conclusion: Preoperative warming of children undergoing spine deformity surgery significantly reduces the percentage of case spent hypothermic, thereby potentially reducing risk of perioperative complications.