Table 2 Univariate and multivariate Wald statistics for predictor variables

Age

3082.7

3

<0.001

814.3

3

<0.001

Heart rate

122.8

3

<0.001

79.4

3

<0.001

Systolic blood pressure

425.3

3

<0.001

107.7

3

<0.001

Oxygen saturation

3502.1

3

<0.001

242.9

3

<0.001

Time to HEMS arrival

80.5

3

<0.001

8.9

3

0.030

GCS

6827.7

2

<0.001

1759.2

2

<0.001

Cardiac rhythm: VF, VT, asystole, or PEA

6613.3

1

<0.001

350.8

1

<0.001

Mission located in medical facility or nursing home, yes

108.4

1

<0.001

0.7

1

0.408

HEMS vehicle, ground unit^a

11.6

1

<0.001

0.6

1

0.444

Sex, male

39.7

1

<0.001

1.0

1

0.325

Patient category

Trauma

21.0

1

<0.001

1.5

1

0.220

Cardiac arrest

871.8

1

<0.001

7.4

1

0.007

Neurological^b

38.9

1

<0.001

10.9

1

<0.001

Psychiatric or intoxication

35.7

1

<0.001

120.9

1

<0.001

Other

34.8

1

<0.001

1.8

1

0.185

Stroke

264.7

1

<0.001

13.7

1

<0.001

Respiratory failure

70.2

1

<0.001

0.2

1

0.664

Chest pain

1.8

1

0.186

0.0

1

0.876