Influence of ambulance arrival on emergency department time to be seen

Objectives. For a limited number of presenting complaints, arrival by ambulance has been shown in some emergency departments to decrease time to be seen by a physician. We sought to determine if this time advantage could be demonstrated as a national trend over a variety of presenting complaints. Methods. A secondary analysis was performed on the National Hospital Ambulatory Medical Care Survey, a national probability sample of emergency department visits. To compare waiting times between patients arriving by ambulance and those arriving by walk-in, a survival analysis was performed using univariate and multivariate Cox proportional hazards models. Primary variables of interest were mode of arrival, waiting time to see physician, and immediacy to be seen ( triage category). The weighted values were utilized to produce national estimates. Patients who left without being seen were treated as right censored data. Results. A total of 61,130 records, weighted to represent 268.3 million emergency department visits from 1997 to 2000, were included in the analysis. Patients arrived by ambulance in 14.4% of these cases. Median wait time for patients arriving by ambulance was 14.1 minutes (95% confidence interval [CI], 4.3 to 34.2) as compared with 26.0 minutes ( 95% CI, 11.5 to 55.1) for patients who arrived by walk-in. In the multivariate analysis, arrival by ambulance offered a 25.0% ( 95% CI, 19.0% to 31.6%) time advantage over walk-in and a 40.8% ( 95% CI, 23.5% to 58.7%) time advantage over arrival by public service. Conclusions. Arrival by ambulance offered a time to be seen advantage for a broad range of presenting complaints in the National Hospital Ambulatory Medical Care Survey across all triage categories.