Mayo Clin Proc. • February 2005;80(2):174-180 • www.mayoclinicproceedings.com 174 EVALUATION OF ICU PERFORMANCE ORIGINAL ARTICLE From the Department of Internal Medicine and Division of Pulmonary and Critical Care Medicine (B.A., R.D.H., O.G., S.G.P.), Department of Anesthesiol- ogy and Division of Intensive Care and Respiratory Care (M.T.K.), and Depart- ment of Health Sciences Research and Division of Health Care Policy and Research (J.M.N., K.H.L.), Mayo Clinic College of Medicine, Rochester, Minn. Supported by a Department of Medicine, Medicine Innovation and Develop- ment System (MIDAS) grant, and the Anesthesia Clinical Research Unit, Department of Anesthesiology. Individual reprints of this article are not available. Address correspondence to Bekele Afessa, MD, Division of Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN 55905 (e-mail: afessa.bekele@mayo.edu). © 2005 Mayo Foundation for Medical Education and Research For editorial comment, see page 164 BEKELE AFESSA, MD; MARK T. KEEGAN, MB, MRCPI; ROLF D. HUBMAYR, MD; JAMES M. NAESSENS, MPH; OGNJEN GAJIC, MD; KIRSTEN HALL LONG, PHD; AND STEVE G. PETERS, MD Evaluating the Performance of an Institution Using an Intensive Care Unit Benchmark OBJECTIVES : To describe the performances of selected intensive care units (ICUs) in a single institution using the Acute Physiology and Chronic Health Evaluation (APACHE) III benchmark and to propose interventions that may improve performance. PATIENTS AND METHODS : In this retrospective study, we analyzed APACHE III data from critically ill patients admitted to ICUs at the Mayo Clinic in Rochester, Minn, between October 1994 and December 2003. We retrieved ICU performance measures based on first ICU day APACHE III values. Standardized ratios were defined as ratios of measured to predicted values. The primary performance measure was the standardized mortality ratio, and secondary performance measures were length of stay (LOS) ra- tios, low-risk monitor ICU admission rates, and ICU readmission rates. We calculated 95% confidence intervals (CIs) for each performance, graded as good, average, or poor. RES ULTS : Among 46,381 patients admitted during the study period, 57.5% were in surgical ICUs, 24.8% in a medical ICU, and 17.7% in a surgical-medical ICU. Low-risk monitoring accounted for 37.2% of admissions. Hospital standardized mortality ratios (95% CI) were 0.95 (0.90-0.99), 0.86 (0.81-0.91), and 0.70 (0.66-0.74) for medical, multispecialty, and surgical ICUs, respec- tively. Hospital LOS ratios (95% CI) were 0.83 (0.81-0.85), 0.91 (0.88-0.93), and 0.99 (0.97-1.00) for medical, multispecialty, and surgical ICUs, respectively. The ICU readmission rate for each ICU was higher than the 6.7% reported in the medical literature. Per- formances were good in mortality, average to good in LOS, aver- age in low-risk admission, and poor in ICU readmission. CONCLUS IONS : A national benchmarking database can highlight the strengths and weaknesses of ICUs. The performances of ICUs in a single institution may differ; therefore, the performance of each unit should be evaluated individually. M ayo Clin Proc. 2005;80(2):174-180 APACHE = Acute Physiology and Chronic Health Evaluation; CI = confi- dence interval; ICU = intensive care unit; IQR = interquartile range; LOS = length of stay; SMR = standardized mortality ratio A lthough the total number of US hospitals has declined in the past 2 decades, the number of intensive care unit (ICU) beds has increased by about 26%. 1 Nationally, from 1985 to 2000 the cost of critical care medicine in- creased from $19.1 billion to $55.5 billion. 1 In the past few years, patients, third-party payers, clinicians, and research- ers have begun to evaluate the performances of ICUs more closely. 2 On the basis of data compiled from Medicare patients, the Solucient Leadership Institute (http://www .solucient.com) identified the 100 hospitals with the best ICUs. Solucient concluded that 30,000 deaths could be avoided and $1.5 billion saved annually if all ICUs per- formed like the best ones. Regulatory agencies and the general public are demanding to know the adequacy of clinicians’ practices. 3 Reflecting the magnitude of the pres- sure, the Joint Commission on Accreditation of Healthcare Organizations (http://www.jcaho.org) is planning to imple- ment severity-adjusted ICU outcome measures, including mortality and length of stay (LOS), by 2005. Measurement of ICU performance is complex and diffi- cult. The University HealthSystem Consortium identified key measures of patient throughput and quality of care as benchmarks for ICU performance. 4 Measures of patient throughput consist of low-risk monitor admission rate and severity-adjusted hospital and ICU LOS; measures of quality of care con- sist of severity-adjusted hospital and ICU mortality and ICU readmission rates. Regardless of other performance, lower-than-expected ICU and hospital mortality rates are prerequisites for an institution to be considered a good performer. 4 Despite the imperfection of the methods, severity ad- justment is an essential component of performance assess- ment. 2,5-7 Previous studies have described ICU severity- adjusted performances among groups of hospitals. 2,7 The business community, hospitals, and physicians in the Cleveland, Ohio, metropolitan area collaborated to pro- duce an ICU performance report in the early 1990s. 2 In a recent publication of Acute Physiology and Chronic Health Evaluation (APACHE) III data for more than 350,000 patients, Zimmerman et al 7 described the charac- teristics of ICUs with superior performance. Published recommendations for improving ICU performance are