Organizational characteristics of intensive care units related to outcomes of abdominal aortic surgery

Abstract

Context: Morbidity and mortality rates in intensive care units (ICUs) vary widely among institutions, but whether ICU structure and care processes affect these outcomes is unknown.

Objective: To determine whether organizational characteristics of ICUs are related to clinical and economic outcomes for abdominal aortic surgery patients who typically receive care in an ICU.

Design: Observational study, with patient data collected retrospectively and ICU data collected prospectively.

Setting: All Maryland hospitals that performed abdominal aortic surgery from 1994 to 1996.

Patients and participants: We analyzed hospital discharge data for patients in non-federal acute care hospitals in Maryland who had a principal procedure code for abdominal aortic surgery from January 1994 through December 1996 (n = 2987). We obtained information about ICU organizational characteristics by surveying ICU medical directors at the 46 Maryland hospitals that performed abdominal aortic surgery. Thirty-nine (85%) of the ICU directors completed this survey.

Main outcome measures: In-hospital mortality and hospital and ICU length of stay.

Results: For patients undergoing abdominal aortic surgery, in-hospital mortality varied among hospitals from 0% to 66%. In multivariate analysis adjusted for patient demographics, comorbid disease, severity of illness, hospital and surgeon volume, and hospital characteristics, not having daily rounds by an ICU physician was associated with a 3-fold increase in in-hospital mortality (odds ratio [OR], 3.0; 95% confidence interval [CI], 1.9-4.9). Furthermore, not having daily rounds by an ICU physician was associated with an increased risk of cardiac arrest (OR, 2.9; 95% CI, 1.2-7.0), acute renal failure (OR, 2.2; 95% CI, 1.3-3.9), septicemia (OR, 1.8; 95% CI, 1.2-2.6), platelet transfusion (OR, 6.4; 95% CI, 3.2-12.4), and reintubation (OR, 2.0; 95% CI, 1.0-4.1). Not having daily rounds by an ICU physician, having an ICU nurse-patient ratio of less than 1:2, not having monthly review of morbidity and mortality, and extubating patients in the operating room were associated with increased resource use.

Conclusions: Organizational characteristics of ICUs are related to differences among hospitals in outcomes of abdominal aortic surgery. Clinicians and hospital leaders should consider the potential impact of ICU organizational characteristics on outcomes of patients having high-risk operations.