International comparison of prehospital trauma care systems

Summary

Objective

Given the recent emphasis on developing prehospital trauma care globally, we embarked upon a multicentre study to compare trauma patients’ outcome within and between countries with technician-operated advanced life support (ALS) and physician-operated (Doc-ALS) emergency medical service (EMS) systems. These environments represent the continuum of prehospital care in high income countries with more advanced prehospital trauma care systems.

Methods

Five countries with ALS-EMS system and four countries with Doc-ALS EMS system provided us with de-identified patient-level data from their national or local trauma registries. Generalised linear latent and mixed models was used in order to compare emergency department (ED) shock rate (systolic blood pressure (SBP) <90 mmHg) and early trauma fatality rate (i.e. death during the first 24 h after hospital arrival) between ALS and Doc-ALS EMS systems. Logistic regression was used to compare outcomes of interest among different countries, accounting for within-system correlation in patient outcomes.

Results

After adjustment for patient age, sex, type and mechanism of injury, injury severity score and SBP at scene, the ED shock rate did not vary significantly between Doc-ALS and ALS systems (OR: 1.16, 95% CI: 0.73–1.91). However, the early trauma fatality rate was significantly lower in Doc-ALS EMS systems compared with ALS EMS systems (OR: 0.70, 95% CI: 0.54–0.91). Furthermore, we found a considerable heterogeneity in patient outcomes among countries even with similar type of EMS systems.

Conclusion

These findings suggest that prehospital trauma care systems that dispatch a physician to the scene may be associated with lower early trauma fatality rates, but not necessarily with significantly better outcomes on other clinical measures. The reasons for these findings deserve further studies.

Introduction

Prehospital care at the scene of injury and during transportation to a medical care facility is often provided by emergency medical service (EMS) systems and is the first step in managing the injured patient. Currently there are four different types of prehospital trauma care systems worldwide. In some environments, there is no organisation responsible for providing prehospital care to trauma patients. This is the pattern in most developing countries.³⁹ Basic life support (BLS) EMS systems provide noninvasive supportive care to trauma patients. The major role of emergency medical technicians (EMTs) in these systems is to transport trauma patients rapidly to a medical care facility and to keep them alive during transport. Some developing countries and many small cities and rural areas in developed countries are served by this type of EMS system.³⁹ Advanced life support (ALS) EMS systems provide more sophisticated care. In these systems, paramedics have intensive training programs for performing invasive procedures such as intubation and intravenous fluid therapy. In the most advanced form of prehospital trauma care (Doc-ALS EMS systems), physicians are responsible for providing prehospital care to trauma patients at the scene of injury and during transport. The primary goal of ALS and Doc-ALS EMS systems is to initiate the highest level of care at scene and during transport.

The gold standard for the evaluation of the effectiveness of different levels of prehospital trauma care is a randomised trial. These randomised trials would almost certainly have to be group-randomised, since the exposure of interest, i.e. types of EMS system, varies at the population level and not at the individual level.³³ However, ethical concerns and resource and infrastructure limitations preclude such trials. Therefore, observational studies have primarily been used to compare patients’ outcome across different systems of prehospital trauma care. However, these studies often suffer from a number of limitations. First, patients within the catchment area of a particular trauma centre often receive prehospital care from a single EMS system. Therefore for an evaluation of the association between type of EMS and patients’ outcome, other settings/areas with different types of EMS systems should be used as controls.³³ This issue requires researchers to design and conduct multicentre studies, taking into consideration the correlation of the observations within centres or systems.1, 9, 10, 11, 14, 15, 26, 33 Second, multicentre studies that evaluate different aspects of trauma care often use the in-hospital trauma fatality rate as the main outcome of interest.3, 31, 47 However, this outcome may be heavily influenced by the quality of hospital care rather than prehospital interventions.17, 27, 28, 33, 44

Considering these limitations, and given the recent emphasis on developing prehospital trauma care globally,³⁹ we embarked upon a multicentre study to compare trauma patients’ outcome across different countries. We sought to test the null hypothesis that patient outcomes do not differ materially between EMS systems. Any superiority of patient outcomes under Doc-ALS compared to ALS EMS systems might be expected to be more prominent for patients with more serious injuries that require higher level of care and more advanced procedures. Due to limited access to the information from countries with BLS EMS system, the focus of this study was on the comparison of the patients’ outcome between ALS and Doc-ALS EMS systems.