Patient flow variability and unplanned readmissions to an intensive care unit

To determine whether high patient inflow volumes to an intensive care unit are associated with unplanned readmissions to the unit.

Retrospective comparative analysis.

The setting is a large urban tertiary care academic medical center.

Patients (n = 3233) discharged from an adult neurosciences critical care unit to a lower level of care from January 1, 2006 through November 30, 2007.

None.

The main outcome variable is unplanned patient readmission to the neurosciences critical care unit within 72 hrs of discharge to a lower level of care. The odds of one or more discharges becoming an unplanned readmission within 72 hrs were nearly two and a half times higher on days when > or =9 patients were admitted to the neurosciences critical care unit (odds ratio, 2.43; 95% confidence interval, 1.39-4.26) compared with days with < or =8 admissions. The odds of readmission were nearly five times higher on days when > or =10 patients were admitted (odds ratio, 4.99; 95% confidence interval, 2.45-10.17) compared with days with < or =9 admissions. Adjusting for patient complexity, the odds of an unplanned readmission were 2.34 times higher for patients discharged to a lower level of care on days with > or =10 admissions to the neurosciences critical care unit (odds ratio, 2.34; 95% confidence interval, 1.27-4.34) compared with similar patients discharged on days of < or =9 admissions.

Days of high patient inflow volumes to the unit were associated significantly with subsequent unplanned readmissions to the unit. Furthermore, the data indicate a possible dose-response relationship between intensive care unit inflow and patient outcomes. Further research is needed to understand how to defend against this risk for readmission.