Prehospital trauma care reduces mortality. Ten-year results from a time-cohort and trauma audit study in Iraq

Abstract

Background: Blunt implementation of Western trauma system models is not feasible in low-resource communities with long prehospital transit times. The aims of the study were to evaluate to which extent a low-cost prehospital trauma system reduces trauma deaths where prehospital transit times are long, and to identify specific life support interventions that contributed to survival.

Methods: In the study period from 1997 to 2006, 2,788 patients injured by land mines, war, and traffic accidents were managed by a chain-of-survival trauma system where non-graduate paramedics were the key care providers. The study was conducted with a time-period cohort design.

Results: 37% of the study patients had serious injuries with Injury Severity Score ≥ 9. The mean prehospital transport time was 2.5 hours (95% CI 1.9 - 3.2). During the ten-year study period trauma mortality was reduced from 17% (95% CI 15 -19) to 4% (95% CI 3.5 - 5), survival especially improving in major trauma victims. In most patients with airway problems, in chest injured, and in patients with external hemorrhage, simple life support measures were sufficient to improve physiological severity indicators.

Conclusion: In case of long prehospital transit times simple life support measures by paramedics and lay first responders reduce trauma mortality in major injuries. Delegating life-saving skills to paramedics and lay people is a key factor for efficient prehospital trauma systems in low-resource communities.

Figure 1

Trauma system expansion by time periods. In period 1 (1997 - 2000, red), the trauma system targeted landmine accidents; in period 2, (2001 - 2003, green), the system was expanded to also include highway road-traffic accidents; in period 3 (2004 - 2006, blue) the system additionally focused on war victims. The referral hospitals (Kirkuk and Suleimaniah Teaching Hospitals) are marked in boxes.

Figure 2

Study patient flow chart. Injuries rated at ISS = 75 are not compatible with survival and patients with this rating were excluded from study. End-point data could not be gathered in patients evacuated to surgical centers outside the study area, and these cases were also excluded from study.

Figure 3

Mortality rate variations by the three time cohorts. The estimates are given with 95% confidence interval bars and demonstrate significant reductions in mortality for Multiple Major and Critical Area injuries (injuries to the head, neck, or torso). The mortality rate in burns increased from period 2 to period 3.

Figure 4

Probabilistic model to identify unexpected survivors and unexpected fatalities. In the scatter plot, survivors and fatalities are grouped by predicted probabilities of death, and physiological severity scores registered at the first in-field encounter (PSS 1). Red rings mark the unexpected survivors and unexpected deaths. Unexpected survivors were defined as survivors with higher than 50% risk of death according to the probabilistic model; unexpected deaths were defined as fatalities with less than 25% risk of death. "Critical area" implies injuries to the head, neck or the torso.