Effect of standing orders on field times.
Because of discontinuation of base hospital participation, paramedics in a large urban zone of a California emergency medical services (EMS) system serving 1.1 million persons went on emergency standing orders for nearly all calls requiring advanced life support. Subsequently, the base hospital resumed medical control function under limited standing orders. Standing orders were allowed for calls that required rapid intervention with little probability of morbidity. The EMS agency conducted a retrospective study to compare times at scene and total prehospital care times before (control group) and after institution of standing orders and limited standing orders. There were significant differences in total prehospital care times and at-scene times between the control group and the two standing order groups (P less than .01). There are important implications to EMS systems that use extensive base hospital contact.