Impact of Obesity on Intensive Care Unit Resource Utilization After Cardiac Operations

Abstract

Background: Much has been published about the effect of obesity on adverse outcomes after cardiac operations, yet little is known regarding the effect of obesity on intensive care unit (ICU) resource utilization. This study examined the effect of obesity on ICU resource utilization after cardiac operations.

Methods: All patients with a body mass index (BMI) of 18.5 kg/m² or higher who underwent a cardiac surgical procedure between 2006 and 2013 were stratified into the following weight categories: normal (BMI 18.5 to 24.99 kg/m²), preobese (BMI 25 to 29.99 kg/m²), obese class I (BMI 30 to 34.99 kg/m²), obese class II (BMI 35 to 39.99 kg/m²), and obese class III (BMI ≥40 kg/m²). Comparisons between weight categories were done, and the risk-adjusted effect of weight category on prolonged ICU stay, prolonged ventilation, and ICU readmission was determined.

Results: Of the 5,365 included patients, 1,948 were obese. Patients with greater obesity experienced longer ICU time, longer ventilation time, and increased ICU readmission. After adjustment, increasing obesity remained independently associated with greater likelihood of prolonged ICU stay (obese class II: odds ratio [OR], 2.4; 95% confidence interval [CI], 1.55 to 3.61; obese class III: OR, 4.1; 95% CI, 2.38 to 7.05), prolonged ventilation (obese class III: OR, 3.4; 95% CI, 1.57 to 7.22), and ICU readmission (obese class II: OR, 3.0; 95% CI, 1.70 to 5.31; obese class III: OR, 2.9; 95% CI, 1.32 to 6.36).

Conclusions: Increasing obesity was associated with a significant increase in ICU resource utilization after cardiac operations. Further study is needed to determine the mechanisms underlying this association and how the adverse effects of obesity may be mitigated.