Table 2.

Predictors of attempted and successful prehospital procedures in multivariable regression models.

			Outcome variables
Predictor variables	Prehospital advanced airway attempt	Prehospital advanced airway success - all patients	IV attempt	IV success - attempts only	IO attempt	IO success - attempts only	IV or IO attempt	IV or IO success - all patients
Female sex	0.85 (0.77–0.93)	0.94 (0.86–1.02)	0.77 (0.70–0.85)	0.64 (0.56–0.73)	1.47 (1.31–1.66)	0.71 (0.48–1.06)	0.87 (0.78–0.98)	0.78 (0.71–0.86)
Age (per 10 years)	1.00 (0.97–1.03)	1.04 (1.01–1.06)	1.01 (0.98–1.04)	1.11 (1.07–1.15)	0.87 (0.84–0.90)	1.12 (1.00–1.26)	0.94 (0.90–0.97)	0.99 (0.96–1.02)
Witnessed arrest	1.05 (0.95–1.15)	1.07 (0.98–1.16)	1.36 (1.23–1.50)	0.91 (0.79–1.04)	0.94 (0.83–1.05)	0.85 (0.57–1.28)	1.36 (1.20–1.53)	1.16 (1.05–1.28)
Public location	1.02 (0.88–1.17)	0.96 (0.85–1.08)	1.09 (0.93–1.27)	1.22 (0.99–1.52)	0.65 (0.53–0.79)	0.61 (0.40–1.08)	0.94 (0.78–1.12)	0.96 (0.83–1.12)
Bystander CPR	1.19 (1.08–1.31)	1.28 (1.17–1.39)	1.06 (0.96–1.18)	1.20 (1.04–1.38)	1.07 (0.95–1.21)	1.52 (0.99–2.32)	1.19 (1.05–1.35)	1.27 (1.14–1.40)
VF/VT first rhythm	1.06 (0.94–1.19)	1.02 (0.92–1.13)	1.73 (1.51–1.98)	1.80 (1.49–2.18)	0.63 (0.53–0.74)	0.71 (0.43–1.18)	1.65 (1.40–1.95)	1.66 (1.45–1.90)

Cases incuded	15,441	15,413	15,483	13,545	15,483	1,296	15,483	15,483
R²	0.0025	0.0030	0.0165	0.0193	0.0208	0.0192	0.0139	0.0129

IV = Intravenous; IO = Intraosseous; CPR = Cardiopulmonary resuscitation; VF/VT = Ventricular fibrillation/ventricular tachycardia