| Methods |
Retrospective cohort, multiple logistic regression and descriptive statistics |
| Participants |
2164 adults (mean age in HEMS group 36.5 years, mean age in GEMS group 47.9 years) transported by HEMS or GEMS January 2003‐December 2008, USA |
| Interventions |
HEMS vs. GEMS transport to a rural level 1 trauma center |
| Outcomes |
Mortality, ICU length of stay, total time in the emergency room, total hospital length of stay, ventilator days, participants discharged to rehabilitation |
| Notes |
Smaller number of participants with higher ISS likely included as evidenced by large confidence intervals in stratified analysis. Interventions and crew expertise not described |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Reporting bias |
Low risk |
9/11 |
| External validity |
Low risk |
3/3 |
| Internal validity |
Low risk |
6/7 |
| Internal validity: confounding and selection bias |
High risk |
3/6 |
| Power |
High risk |
0/5 |
