1. University at Buffalo Dept. of Anesthesiology, Buffalo, NY
PATIENT AND SURGICAL FACTORS FOR PREDICTING POSTOPERATIVE HYPOTHERMIA AFTER ABDOMINAL SURGERY
Ognjen Visnjevac, MD, Remek Kocz, MD, Paul Kim, MD, Max Hsia, MD, Dario Jeginovic, BSc, Erik Jensen, MD, Jonathan Grande, MD, Nader D. Nader, MD, PhD, FCCP
University at Buffalo Dept. of Anesthesiology, Buffalo, NY
Introduction / Background
Perioperative hypothermia has been associated with a number of complications and active patient warming has been found to be beneficial. (1-4) Various warming strategies have been studied, but there is paucity of information regarding patient factors contributing to perioperative hypothermia. Body mass index (BMI) and body surface (BSA) have been documented to affect the rate of patient rewarming, but these studies had small sample sizes. (5-7) Intravenous (IV) acetaminophen, an effective antipyrectic with an as-of-yet unclear mechanism of action, has also become one of the most commonly used intraoperative analgesics with no published reports of this medication’s effects on perioperative thermoregulation. (8)
It was hypothesized that a BMI:BSA ratio would be a useful predictive index for postoperative hypothermia and that intraoperative IV acetaminophen use and longer operative times would be associated with postoperative hypothermia.
Results
Preoperative Temperature as a Predictor of Temperature Change
Predictors of Postoperative Hypothermia (<36°C)
Figure 1
Logistic regression analysis for predicting postoperative hypothermia
(< 36°C). Age, total operating room time, laparoscopic and peripheral
procedures, IV acetaminophen use, BMI, and BMI:BSA ratio were not
found to be significant predictors of postoperative hypothermia.
OR = Odds Ratio.
Figure 2.
Linear regression analysis for preoperative temperature as a predictor of temperature change. (Intercept 23.67, B = -0.65, 95% CI to -0.62, P<0.0001).
Variable OR
95% Confidence Interval
P-value
BSA
0.39
0.016
Intracavitary Procedures
1.95
0.036
Preoperative Hypothermia
35.34
<
Methods
A retrospective review of perioperative temperature change was undertaken to assess the impact and relationship between BMI, BSA, and intraoperative IV acetaminophen use and other patient and surgical factors (Figure 1) on perioperative temperature change for abdominal surgeries at 3 hospitals over a 2-year period.
Data for 5168 consecutive adult abdominal procedures separated into laparoscopic, intracavitary, or peripheral surgeries were analyzed. Multivariate analyses were utilized to identify significant variables contributing to perioperative hypothermia (<36°C) and the degree of temperature change. All patients received general anesthesia and forced-air warming blankets, per hospital protocol.
Conclusions
This is the first large study to assess the impact of patient and surgical factors on perioperative heat loss in abdominal surgery. BMI:BSA was shown to be an inferior index than BSA alone for predicting postoperative hypothermia and intraoperative IV acetaminophen use was not found to be an independent predictor of temperature change. Intracavitary procedures were identified as a high-risk (OR 1.95) for developing perioperative hypothermia. Preoperative hypothermia was the most significant factor associated with postoperative hypothermia (OR 35.34), suggesting that studies focusing on preoperative patient warming may yield interventions with the greatest impact on prevention of postoperative hypothermia.
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