The Effect of Organ System Surgery on Intensive Care Unit Mortality in a Cohort of Critically Ill Surgical Patients

Abstract

Background The critical illness burden in the United States is growing with an aging population obtaining surgical intervention despite age-related comorbidities. The effect of organ system surgical intervention on intensive care units (ICUs) mortality is unknown. Methods We performed an 8-year retrospective analysis of surgical ICU patients. Poisson regression analysis was performed assessing the relative risk of in-hospital mortality based on surgical intervention. Results Of 468 000 ICU patients included, 97 968 (20.9%) were surgical admissions and 97 859 (99.9%) had complete outcomes data. Nonsurvivors were older (68.8 ± 15.4 vs. 62.7 ± 15.8 years, P < .001) with higher Acute Physiology, Age, Chronic Health Evaluation (APACHE) III Scores (81.4 ± 33.6 vs. 46.7 ± 20.1, P < .001. Patients with gastrointestinal (GI) (n = 1,558, 7.8%), musculoskeletal (n = 277, 5.5%), and neurological (n = 884, 4.6%) system operations had the highest mortality. Upon Poisson regression model, patients undergoing emergent operative interventions on the neurologic system (RR 1.86, 95% CI 1.67-2.07, P < .001) had increased relative risk of mortality when compared to emergent operative interventions on the cardiovascular system after controlling for pertinent covariates. Elective operative interventions on the respiratory (RR 2.39, 95% CI 2.03-2.80, P < .001), GI (RR 2.34, 95% CI 2.10-2.61, P < .001), and skin and soft tissue (RR 2.26, 95% CI 1.77-2.89, P < .001) systems had increased risk of mortality when compared to elective cardiovascular system surgery after controlling for pertinent covariates. Conclusion We found significant differences in the risk of mortality based on organ system of operative intervention. The prognostication of critically ill patients undergoing surgical intervention is currently not accounted for in prognostic scoring systems.