High occupancy increases the risk of early death or readmission after transfer from intensive care*

Abstract

To determine whether a lack of intensive care unit beds was leading to premature patient discharge from the intensive care unit and subsequent early readmission or death. Prospective cohort study. A single Canadian tertiary care teaching hospital. All intensive care unit admissions between January 1, 1989 and December 31, 1996 were collected prospectively for inclusion in a registry database. None. There was a positive correlation between early readmission or death and average quarterly intensive care unit percent occupancy (p = .001). During the study period, 8693 patients experienced 10,185 admissions to intensive care. Of the 8222 patients remaining under active treatment (patients under palliative care were excluded), there were 455 (5.5%) adverse events (431 intensive care unit readmissions and 24 deaths) in the first 7 days post intensive care unit discharge. Patients requiring a new surgical intervention with postoperative intensive care unit admission were not considered readmissions. In a multivariate analysis, significant risk factors for an adverse event included age >35 yrs, particular diagnoses (respiratory diagnoses, sepsis, neurosurgery, thoracic surgery, and gastrointestinal diagnoses), Acute Physiology and Chronic Health Evaluation II score, and intensive care unit length of stay. Discharge from the intensive care unit at a time of no vacancy was also a significant risk factor for intensive care unit readmission or unexpected death with an adjusted relative risk of 1.56 (95% confidence interval 1.05, 2.31). Increased patient occupancy within an intensive care unit is associated with an increased risk of early death or intensive care unit readmission post intensive care unit discharge. Overloading the capacity of an intensive care unit to care for critically ill patients may affect physician decision-making, resulting in premature discharge from the intensive care unit.