Obesity associated with increased postoperative pulmonary complications and mortality after trauma laparotomy

Patient-related risk factors for the development of postoperative pulmonary complications (PPCs) include age ≥ 60-years, congestive heart failure, hypoalbuminemia and smoking. The effect of obesity is unclear and has not been shown to independently increase the likelihood of PPCs in trauma patients undergoing trauma laparotomy. We hypothesized the likelihood of mortality and PPCs would increase as body mass index (BMI) increases in trauma patients undergoing trauma laparotomy.

The Trauma Quality Improvement Program (2010-2016) was queried to identify trauma patients ≥ 18-years-old undergoing trauma laparotomy within 6-h of presentation. A multivariable logistic regression analysis was used to determine the likelihood of PPCs and mortality when stratified by BMI.

From 8,330 patients, 2,810 (33.7%) were overweight (25-29.9 kg/m²), 1444 (17.3%) obese (30-34.9 kg/m²), 580 (7.0%) severely obese (35-39.9 kg/m²), and 401 (4.8%) morbidly obese (≥ 40 kg/m²). After adjusting for covariates including age, injury severity score, chronic obstructive pulmonary disease, smoking, and rib/lung injury, the likelihood of PPCs increased with increasing BMI: overweight (OR = 1.37, CI 1.07-1.74, p = 0.012), obese (OR = 1.44, CI 1.08-1.92, p = 0.014), severely obese (OR = 2.20, CI 1.55-3.14, p < 0.001), morbidly obese (OR = 2.42, CI 1.67-3.51, p < 0.001), compared to those with normal BMI. In addition, the adjusted likelihood of mortality increased for the morbidly obese (OR = 2.60, CI 1.78-3.80, p < 0.001) compared to those with normal BMI.

Obese trauma patients undergoing emergent trauma laparotomy have a high likelihood for both PPCs and mortality, with morbidly obese trauma patients having the highest likelihood for both. This suggests obesity should be accounted for in risk prediction models of trauma patients undergoing laparotomy.