Introducing an on-site Helicopter Emergency Medical Service (HEMS) physician at the Emergency Medical Communication Centre - implications for dispatch precision at a Norwegian HEMS base

Table 4 Primary and secondary outcome analyses

Outcome	Unit	Difference in differences, Estimate (95% CI)¹	Unit	Intervention versus non-intervention, Estimate (95% CI)^1,2
Unnecessary mission	%-point RD	5.6 (-7.4 to 18.6)	OR	1.36 (0.82 to 2.26)
NACA score 4 to 7	%-point RD	-5.8 (-17.9 to 6.3)	OR	1.20 (0.69 to 2.11)
Time from 113 call to HEMS alarm	Minutes	0.9 (-7.7 to 9.5)	Minutes	0.7 (-5.6 to 7.0)
Time from HEMS alarm to take-off	Minutes	3.1 (-1.9 to 8.1)	Minutes	2.1 (-1.5 to 5.7)

¹Analyses were adjusted for EMCC physician. ²Analyses were adjusted for day of the year, time of the day and age and sex of the patient. OR: Odds ratio, CI: Confidence interval, RD: Risk difference, NACA: National Advisory Committee for Aeronautics

ISSN: 1757-7241