On-line medical command in theory and practice.

Paramedics are often required to use on-line medical command (OLMC) when they provide advanced life support. We evaluated the efficacy of OLMC use under this broad patient inclusion rule and limited paramedic discretion. OLMC was associated with an average of an eight-minute longer on-scene time, and an infrequent rate of physician-directed deviation from written treatment protocols (3.7% of all OLMC calls). Of the system's advanced life support patients, 6.1% experienced changes in their prehospital health status, reflected in changes in the patient's level of consciousness. OLMC use was associated with improved health status in 5.5% of patients compared with 3.2% for those treated without OLMC (P = .1). The health status of 1.3% of the patients treated with OLMC deteriorated. This was not significantly different from the 1.1% of patients treated without OLMC whose status deteriorated. We suggest that targeted OLMC use with expanded paramedic discretion may improve the efficacy of OLMC. Further controlled comparative studies of OLMC efficacy under targeted OLMC use versus broad patient inclusion rules are needed.