Burt CW, McCaig LF, Valverde RH. Analysis of ambulance transports and diversions among US emergency departments. Ann Emerg Med. 2006;47(4):317-236.

Emergency nurses are concerned about ambulance diversion. This common operating procedure for many emergency departments occurs in response to department overcrowding caused by a high volume of patients or a backlog of admissions.

This study reviews the volume of emergency department (ED) ambulance arrivals and transfers. Estimates are calculated for the frequency of and reasons for ambulance diversion. Then, using ambulance transfer data, the probability of an ED being in diversion status is applied to arrive at the estimated number of patients for whom care is delayed because of ambulance diversion status. Using 2003 data, the authors report that 14.2% of all ED patients arrived by ambulance. Of that number, 39% are seniors, 68% are triaged as emergency or urgent, and 37% are admitted. In addition, of the hospital ED's that practice ambulance diversion, an estimated 3% of the operating time is spent in this status, resulting in 1 ambulance diverted per minute, nationally. This study is the first to estimate the volume and frequency of national ambulance diversions.

The authors do a remarkable job of using statistical calculations to reach their conclusions and prove what most emergency nurses know: most diversions occur in metropolitan areas, ambulance transport for illness is greatest on Mondays, peak time of ambulance arrival is from 10 AM to 1 PM, and 5 to 7 PM, patients transported by ambulance generally need more diagnostic services and therapeutic interventions.

One of the key conclusions the authors state is that diverting an ambulance and thereby delaying care leads to increased morbidity and mortality. Another conclusion is that the problem of ED overcrowding, which is the root cause of ambulance diversion, will not go away, and will most likely increase as the overall population ages. EDs and hospitals must begin to plan now for the change in population needs (17 references).

This study cements the effects of ED overcrowding on ambulance diversions into astounding numbers. Individual EDs may be able to apply the data to their own circumstances to move hospital administration to engage in planning and change. For the average emergency nurse, the methodology and statistical discussions within the article may be cumbersome; however, comprehensive data tables are provided for individual analysis and comparison to particular areas of practice.