USE OF INTENSIVE-CARE UNITS FOR PATIENTS WITH LOW SEVERITY OF ILLNESS

Objective: To determine variations among hospitals in use of intensive care units (ICUs) for patients with low severity of illness. Design: Retrospective cohort study. Setting: Twenty-eight hospitals with 44 IC Us in a large metropolitan region. Patients: Consecutive eligible pati ents (N = 104 487) admitted to medical, surgical, neurological, or mix ed medical-surgical ICUs from March 1, 1991, to March 31, 1995. Outcom e Measures: The predicted risk of in-hospital death for each patient w as assessed using a validated method that is based on age, ICU admissi on source, diagnosis, severe comorbid conditions, and abnormalities in 17 physiologic variables. Admissions were classified as low severity if the patient's predicted risk of death was less than 1%. In a subset of 12 929 consecutive patients, use of 19 specific interventions typi cally delivered in ICUs was examined. Results: Twenty thousand four hu ndred fifty-one admissions (19.6%) were categorized as low severity, i ncluding 23.6% of postoperative and 16.9% of nonoperative admissions. Alcohol and other drug overdoses accounted for 40.2% of nonoperative l ow-severity admissions; laminectomy and carotid endarterectomy account ed for 52.3% of postoperative low-severity admissions. Mortality among patients with low-severity illness was 0.3%, and only 28.6% received an ICU-specific intervention during the first ICU day. Although mean I CU length of stay was shorter (P<.001) in low-severity admissions (2.2 vs 4.7 days in nonoperative and 2.4 vs 4.2 days in postoperative admi ssions), low-severity admissions accounted for 11.1% of total ICU bed days. Rates of low-severity admissions varied (P<.001) across hospital s, ranging from 5% to 27% for nonoperative and 9% to 68% for postopera tive admissions. Conclusions: A large proportion of patients admitted to the ICU have a low probability of death and do not receive ICU-spec ific interventions. Rates of low-severity admissions varied among hosp itals. The development and implementation of protocols to target ICU c are to patients most likely to benefit may decrease the number of low- severity ICU admissions and improve the cost-effectiveness of ICU care .