Morbid obesity in the medical ICU

Study objective: To describe the clinical course, complications, and prognostic factors of morbidly obese patients admitted to the ICU compared to a control group of nonobese patients. Design: A retrospective study. Setting: Two university-affiliated hospitals. Methods: We reviewed the medical records of 117 morbidly obese patients (body mass index ≥ 40 kg/m²) admitted to the medical ICU between January 1994 and June 2000. Data collected included demographic information, comorbid condition, APACHE (acute physiology and chronic health evaluation) II score, invasive procedures, organ failure, and in-hospital mortality. Results: Obstructive airway disease, pneumonia, and sepsis were the main reasons for admission to the ICU in the morbidly obese group. Sixty-one percent of the morbidly obese patients and 46% of the nonobese group required mechanical ventilation (p = 0.02). The mean lengths of mechanical ventilation and ICU stay were significantly longer for the morbidly obese group (7.7 ± 9.6 days and 9.3 ± 10.5 days vs 4.6 ± 7.1 days and 5.8 ± 8.2 days, respectively; p < 0.001). APACHE II scores were not significantly different in the two groups (19.1 ± 7.6 and 20.6 ± 12.2; p = 0.6). Overall mortality was 30% for the morbidly obese patients and 17% for the nonobese group (p = 0.019). By multivariate analysis, multiorgan failure (odds ratio [OR], 4.6; 95% confidence interval [CI], 2.1 to 16.6), Pao₂/fraction of inspired oxygen < 200 for > 48 h (OR, 2.3; 95% CI, 1.2 to 7.8), and depressed left ventricular ejection fraction < 40% (OR, 1.4; 95% CI, 1.03 to 13.8) were independently associated with ICU mortality in the morbidly obese group. Conclusion: We conclude that critically ill morbidly obese patients are at increased risk of morbidity and mortality compared to the nonobese patients.