Table 2 Variables included in the final model of RISC II, and prevalence of missing values

Worst injury, second-worst injury

AIS injury severity level; if only one injury was coded, the second-worst injury was set to zero

0%

Head injury

AIS injury severity level of the body region `head' as defined for the ISS score

0%

Age

Age in years at the time of accident, 10 categories

0%

Sex

Males/females

0.9%

ASA

Pre-trauma ASA (American Society of Anesthesiologists) score, as defined in the Utstein core dataset [5]

16.3%

Pupil reactivity

Three categories according to the Eppendorf-Cologne Scale (ECS) [12]: brisk, sluggish, and none. The first pre-hospital assessment was used; if missing; assessment on admission was used

53.5%*

Pupil size

Three categories according to the Eppendorf-Cologne Scale [12]: normal, anisocoria, and bilateral dilated. The first pre-hospital assessment was used; if missing; assessment on admission was used

54.9%*

Motor function

The motor function was derived from the Glasgow Coma Store (GCS) motor score according to the Eppendorf-Cologne scale [12]: normal (6 points in GCS); directed (4-5); non-directed (2-3), and none (1). The first pre-hospital assessment was used if available; if missing assessment on admission was used in non-intubated cases

2.7%

Mechanism

Blunt or penetrating mechanism of injury

6.1%

Blood pressure

Systolic blood pressure (mmHg), first measurement after admission; in case of missing values the first pre-hospital measurement was used

10.7%

Coagulation: INR

International normalized ratio (INR); first measurement after admission

12.9%

Acidosis: base deficit

Base deficit, or base excess (mEq/l); first measurement after admission

46.0%

Blood: haemoglobin

Haemoglobin (g/dl); first measurement after admission

7.6%

CPR

Cardiopulmonary resuscitation (CPR), performed pre-hospitally in case of cardiac arrest (not in the emergency room)

3.2%