Normothermia to prevent surgical site infections after gastrointestinal surgery: holy grail or false idol?

Abstract

Objective: To analyze the association between perioperative normothermia (temperature ≥36°C) and surgical site infections (SSIs) after gastrointestinal (GI) surgery.

Summary of background data: Although active warming during colorectal surgery reduces SSIs, there is limited evidence that perioperative normothermia is associated with lower rates of SSI. Nonetheless, hospitals participating in the Surgical Care Improvement Project must report normothermia rates during major surgery.

Methods: We conducted a nested, matched, case-control study; cases consisted of GI surgery patients enrolled in our National Surgical Quality Improvement Program database between March 2006 and March 2009 who developed SSIs. Patient/surgery risk factors for SSI were obtained from the National Surgical Quality Improvement Program database. Perioperative temperature/antibiotic/glucose data were obtained from medical records. Cases/controls were compared using univariate/random effects/logistic regression models. Independent risk factors for SSIs were identified using multivariate/random effects/logistic regression models.

Results: A total of 146 cases and 323 matched controls were identified; 82% of patients underwent noncolorectal surgery. Cases were more likely to have final intraoperative normothermia compared with controls (87.6% vs. 77.8%, P = 0.015); rates of immediate postoperative normothermia were similar (70.6% vs. 65.3%, respectively, P = 0.19). Emergent surgery/higher wound class were associated with higher rates of intraoperative normothermia. Independent risk factors for SSI were diabetes, surgical complexity, small bowel surgery, and nonlaparoscopic surgery. There was no independent association between perioperative normothermia and SSI (adjusted odds ratio, 1.05; 95% confidence interval, 0.48-2.33; P = 0.90).

Conclusions: Pay-for-reporting measures focusing on perioperative normothermia may be of limited value in preventing SSI after GI surgery. Studies to define the benefit of active warming after noncolorectal GI surgery are warranted.

FIGURE 1

Normothermia (T ≥36.0°C) rates at various perioperative time points according to emergency versus elective surgery status.

FIGURE 2

Normothermia (T ≥36.0°C) rates at various perioperative time points according to wound class.

FIGURE 3

Perioperative normothermia (final intraoperative temperature or first postoperative T ≥36.0°C) of cases and controls, stratified by type of surgery. CR indicates colorectal.