Very little evidence is available on the experience of ambulance-personnels or on the impact of prehospital interventions on total prehospital time.

On-scene-time increases with the number of prehospital techniques used, and ambulance-technicians achieve only limited clinical experience in prehospital techniques.

Prospective, observational registry study including 56 ambulance technicians from two ambulance stations in the mixed urban/rural county and 5,557 patients who were brought to a hospital in 1998. The number of cases in which each ambulance-technician performed various kinds of prehospital techniques, and the average on-scene time for each prehospital technique and several combinations of prehospital techniques were calculated.

There were large differences between the number of times each technique was used. On-scene time was smallest when no techniques were used and tended to increase with the number of interventions used. On-scene-time was relatively low for patients with cardiac arrest.

The Danish ambulance-technicians' curriculum includes interventions for which the technicians only achieve limited practical experience. Prehospital interventions are associated with an increase of on-scene time.