Do ambulance crews with one advanced paramedic skills officer have longer scene times than crews with two?

OBJECTIVE In 1999, the Metropolitan Ambulance Service (MAS), Melbourne, Australia began implementing The Emergency Operations Plan (1998). One of the initiatives of the plan was the addition of crews with one advanced paramedic skills (APS) officer and one non-APS officer (mixed crews). All previous APS crews contained two APS officers working together. There was concern that mixed crews would have longer scene times than all-APS crews. This study aims to compare scene times at time critical cases for mixed crews and all-APS crews. METHOD Prospective, non-randomised comparison of scene times for time critical cases for three mixed crew units and three all-APS units for the months of August to October 1999. The crew types were also compared by explicit retrospective audit for rates of APS procedures attempted and APS procedure failure rates. Data were analysed using SPSS, t test, and chi(2) test where appropriate. RESULTS There were 1700 time critical cases in the study period of which 1537 had valid data for the calculation of scene times. A total of 714 cases were attended by mixed crews and 823 cases by all-APS crews. The mean scene time for mixed crews was 15.54 minutes compared with 16.92 minutes for all-APS crews. This difference is statistically significant (p=0.002). All-APS crews performed a slightly higher number of APS procedures (0.90/time critical case versus 0.76/time critical case; p=0.001). There was no significant difference in procedure failure rates. CONCLUSION Mixed crews demonstrated shorter scene times than all-APS crews, although this is unlikely to be clinically significant. The concern that mixed crews would have longer scene time was not substantiated and should not be considered as a barrier to the development of mixed crew staffing models.