Study characteristics.

a In- and exclusion criteria for the population of interest.
b Number of population on which the analyses of interest (prehospital intubation versus no intubation in TBI patients) are based. If multiple analyses are presented in the manuscript, the range of the number of patients used in the analyses is reported.
c Data from the studies by Bukur and Karamanos report patients from the same region and overlapping time period.
d Data from the studies by Davis, Poste, Sloane and Winchell are all from the same region and overlapping time periods and partially report overlapping data.
e Total number of patients in study, unclear whether all are included in analysis of interest.
f Data are from the National Trauma Data Bank and might include some patients that have also been included to other studies that have been performed in the USA.
ABG: arterial blood gas
(H-)AIS: (head) abbreviated injury scale
CPR: cardiopulmonary resuscitation
CT: computed tomography
ED: emergency department
GCS: Glasgow Coma Scale
ICU: intensive care unit
ICD-9-CM: international classification of diseases, 9th revision, clinical modification
ISS: injury severity scale
NR: not reported
OR: operating room
RCT: randomized controlled trial
RSI: rapid sequence induction
TBI: traumatic brain injury
Study characteristics.