Intraoperative Hypothermia and Surgical Site Infections in Patients with Class I/Clean Wounds: A Case-Control Study

Abstract

Numerous surgical quality metrics focus on prevention of unintentional perioperative hypothermia due, in part, to the association between hypothermia and surgical site infections (SSI). However, few studies have comprehensively evaluated the relationship between these metrics and SSI. In this study, we evaluated individual components of 1 set of hypothermia metrics to determine their association with SSI. Patients with clean (class I) wounds who developed an SSI within 30 days after surgery, from January 2003 to December 2012, in 1 of 5 surgical specialties, were matched to specialty-specific controls without SSI. Stratified logistic regression models were used to assess the associations between (1) compliance with the Surgical Care Improvement Project (SCIP) Performance Measure, Surgery Patients with Perioperative Temperature Management (SCIP-Inf-10), overall and its components (maintenance of minimum body temperature and use of an active warming device) and SSI and (2) intraoperative hypothermia. In both univariate and adjusted analyses using adjusted odds ratios (OR), SCIP-Inf-10 compliance was not associated with SSI (composite compliance OR 0.89, 95% CI 0.63 to 1.24; temperature compliance OR 0.92, 95% CI 0.78 to 1.09; forced-air warming device compliance OR 0.95, 95% CI 0.76 to 1.19). Higher intraoperative nadir temperature (OR 1.19, 95% CI 1.05 to 1.35) was associated with SSI. Percent of time exposed to a temperature < 36°C (OR 0.98, 95% CI 0.96 to 1.01), and cumulative hypothermic exposure (°C*h <36°C) (OR 0.98, 95% CI 0.90 to 1.05) were not associated with SSI. Intraoperative hypothermia was not significantly associated with SSI. These results suggest that development of compliance metrics may not be an effective strategy for SSI reduction in class I surgical wounds.