N Engl J Med. 2006 Jul 6;355(1):41-50.
Kahn JM, Goss CH, Heagerty PJ, Kramer AA, O’Brien CR, Rubenfeld GD.
Division of Pulmonary and Critical Care Medicine, University of Washington,
Seattle 98104, USA.
BACKGROUND: An increased volume of patients is associated with improved survival
in numerous high-risk medical and surgical conditions. The relationship between
the number of patients admitted (hospital volume) and outcome among patients with
critical illnesses is unknown. METHODS: We analyzed data from 20,241 nonsurgical
patients receiving mechanical ventilation at 37 acute care hospitals in the Acute
Physiology and Chronic Health Evaluation clinical information system from 2002
through 2003. Multivariate analyses were performed to adjust for the severity of
illness and other differences in the case mix. RESULTS: An increase in hospital
volume was associated with improved survival among patients receiving mechanical
ventilation in the intensive care unit (ICU) and in the hospital. Admission to a
hospital in the highest quartile according to volume (i.e., >400 patients
receiving mechanical ventilation per year) was associated with a 37 percent
reduction in the adjusted odds of death in the ICU as compared with admission to
hospitals in the lowest quartile (< or =150 patients receiving mechanical
ventilation per year, P<0.001). In-hospital mortality was similarly reduced
(adjusted odds ratio, 0.66; 95 percent confidence interval, 0.52 to 0.83;
P<0.001). A typical patient in a hospital in a low-volume quartile would have an
adjusted in-hospital mortality of 34.2 percent as compared with 25.5 percent in a
hospital in a high-volume quartile. Among survivors, there were no significant
trends in the length of stay in the ICU or the hospital. CONCLUSIONS: Mechanical
ventilation of patients in a hospital with a high case volume is associated with
reduced mortality. Further research is needed to determine the mechanism of the
relationship between volume and outcome among patients with a critical illness.
Copyright 2006 Massachusetts Medical Society.