Ambulance diversion and lost hospital revenues.

STUDY OBJECTIVE: We estimate ambulance revenues lost from each hour spent on ambulance diversion at an urban teaching hospital's emergency department (ED) and examine the financial impact of increased ICU capacity, which reduced diversion hours by 63%.

METHODS: This was a secondary analysis of administrative data to determine the time and date of ambulance arrivals, as well as the insurance status and revenues from each ED patient arriving by ambulance between January 1, 2002, and December 31, 2003. The primary outcome measure was hourly revenues (ie, payments to the hospital) for ambulance patients.

RESULTS: Ten thousand three hundred one adult, non-trauma-system ED patients arrived by ambulance in 2002 and 2003, with average hospital revenues of 4,492 dollars. Each hour spent on diversion was associated with 1,086 dollars (95% confidence interval 611 dollars to 1,461 dollars) in forgone hospital revenues from ambulance patients. In August 2002, the study hospital increased its staffed ICU beds from 47 to 67, and diversion decreased from an average of 307 to 114 hours per month. In association with the reduction in diversion, the hospital received more patients by ambulance, which translated into approximately 175,000 dollars in additional monthly revenues from ambulance patients. However, these gains were relatively small in relation to total ambulance revenues and to their large monthly variance.

CONCLUSION: Ambulance patients generated substantial revenues for hospital services. Decreasing diversion time led to improved revenues. The potential for increased revenues may provide some incentive for hospitals to take greater efforts to reduce ambulance diversion.