1) There is no increase in transport or scene time of diverted patients and no increase in distances traveled; 2) hospital resource shortages bear no relationship to the number of patients diverted; and 3) paramedics are able to match their patient correctly with the resources available at a given hospital.

This was a five-month, prospective, observational study in an urban area with a population of 600,000 comparing all 9-1-1 ambulance diversions against a randomly selected sample of 5% of all other 9-1-1 originated patients. All patient diversions that originated from the 9-1-1 center are included in the study.

Hospitals identify their diversion status on a community-wide computer system monitored at the 9-1-1 center and base station. Accepted categories include: 1) diversion of all patients through the 9-1-1 center from the emergency department (ED); 2) trauma system patients (T); 3) psychiatric secure beds (PSB); 4) general acute ward beds (AW); 5) critical care (CC); 6) computed tomography scan (CT); 7) labor and delivery (LD); and 8) pediatric beds (PEDS). Data were abstracted from 481 patients' records. A total of 111 were diverted from their intended destination. Transport times were longer and diverted patients traveled further (p <.002). Hospitals showing ED and LD diversion categories were more likely to have patients diverted away (r2 = .895, multilinear regression, p <.001). Of the 111 patients, 21 (19%) were diverted because of CC unavailability. Six of these (28%) were inappropriate because they did not fit the CC definition.

In this system, hospital diversions increase transport times and distances traveled. Diversion of patients correlated strongly to unavailability of specific categories. Paramedics make errors in determining appropriate CC diversions. Systems reviewing their diversion problems need to assess the impact of longer out-of-hospital times and of certain diversion categories, and to clarify definitions.