Multicenter Canadian Study of Prehospital Trauma Care

Moishe Liberman, MD, David Mulder, MD, André Lavoie, PhD, Ronald Denis, MD, John S. Sampalis, PhD

Disclosures

Annals of Surgery. 2003;237(2) 

In This Article

Abstract and Introduction

Objective: To evaluate whether the type of on-site care a trauma patient receives affects outcome.
Summary Background Data: The controversy regarding the prehospital care of trauma patients between Advanced Life Support (ALS) and Basic Life Support (BLS) is ongoing. Due to this unresolved controversy, as well as historical, cultural, and political factors, there are significant variations with respect to the type of prehospital care available for trauma patients.
Methods: This prospective cohort study compared three types of prehospital trauma care systems: Montreal, where physicians provide ALS (MD-ALS); Toronto, where paramedics provide ALS (PMD-ALS); and Quebec City, where emergency medical technicians provide BLS only (EMT-BLS). The study took advantage of this variation to evaluate the association between the type of on-site care and mortality in patients with major life-threatening injuries. All patients were treated at highly specialized tertiary (level I) trauma hospitals. The main outcome measure was death as a result of injury. Follow-up was to hospital discharge.
Results: The overall mortality rates by type of on-site personnel were physicians 35%, paramedics 24%, and EMTs 18%. For patients with major but survivable trauma, the overall mortality rates were physicians 32%, paramedics 28%, and EMTs 26%. The overall mortality rate of patients receiving only BLS at the scene was 18% compared to 29% for patients receiving ALS. For the subgroup of patients with major but survivable injuries, the mortality rates were 30% for ALS and 26% for BLS. The adjusted increased risk for mortality in patients receiving ALS at the scene was 21%.
Conclusions: In urban centers with highly specialized level I trauma centers, there is no benefit in having on-site ALS for the prehospital management of trauma patients.

In the Western world, trauma is the leading cause of death for individuals under 45 years of age, and it remains the fourth leading cause of death for all ages combined.[1,2] In 1994, 8,687 people died following accidents in Canada.[3] Approximately four times as many patients suffer severe disability related to accidents each year.

Prehospital care for trauma patients is provided by emergency medical personnel using either Basic Life Support (BLS) or Advanced Life Support (ALS) techniques. BLS (or "scoop and run") consists of noninvasive interventions such as wound dressing, immobilization, fracture splinting, oxygen administration, and noninvasive cardiopulmonary resuscitation. ALS encompasses all of these BLS techniques in addition to invasive procedures, including intubation, initiation of IV access with fluid replacement, administration of medications, and in rare cases application of pneumatic antishock garments (PASG). The rationale for the use of on-site ALS in trauma is that these interventions will reduce the rate of physiologic and hemodynamic deterioration, thus stabilizing the patient before arrival at the hospital. It is expected that this will result in increased chances of survival. The paradox is that on-site ALS increases the amount of time that is spent on the scene and hence increases the delay to definitive in-hospital care. To date, the controversy between the "scoop and run" versus "stay and stabilize" approach to prehospital trauma care remains unresolved and has been the subject of a limited number of studies, most of which were based on small numbers of selected patients. Studies supporting ALS have failed to show an association between on-site ALS and increased survival among patients with major trauma.[4,5,6,7,8,9,10,11,12,13,14] Studies supporting BLS have shown higher survival rates for patients treated using the "scoop and run" approach compared to those treated using on-site ALS.[15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30] The validity of these studies is often compromised due to the lack of control for confounding variables and appropriate comparison groups.

A 1992 study by Schmidt et al.[31] compared trauma patients with equivalent Injury Severity Scores (ISS) transported by helicopter in Germany to patients transported by helicopter in the United States. In Germany, patients received treatment by a paramedic and a trauma surgeon and in the United States by a paramedic and a nurse. They found that the German patients received significantly more advanced interventions, including IV fluids, endotracheal intubations, and thoracic decompressions, than the American group. This led to a decrease in early mortality and improved outcome compared to patients in the Major Trauma Outcome Study (MTOS).

In addition to increasing prehospital delays, the argument against "stay and stabilize" is strengthened because none of the specific ALS interventions has been proven to be beneficial for the prehospital management of severely injured patients. The rationale for using on-site IV line placement and fluid infusion is that it will control hemodynamic deterioration. The amount of fluid infused, however, cannot compensate for the blood lost in a severely bleeding patient; for such cases the definitive treatment is surgery.[8,19,20] The time required to start an IV on the scene is a matter of debate: certain authors report minimal times between 2 and 4 minutes,[10,32,33,34,35,36] while others show times of 12 minutes or more.[18,37] There are no controlled studies evaluating the impact of IV placement on patient outcome.

Similarly, the effectiveness of on-site intubation in improving outcome of severely injured patients has not been adequately evaluated. The rationale for on-scene intubation is that this intervention will maintain airway patency and oxygenation.[38] As with IV placement, the argument against intubation is that it causes significant delays to definitive in-hospital care. Unlike IV placement, however, there is some agreement that in certain severely injured and unconscious patients, intubation should be initiated at the scene or en route to the hospital.[7,19,38]

The only ALS intervention subjected to evaluation by randomized controlled trials is PASG. A series of such studies failed to demonstrate any benefit and in some cases showed an increase in adverse outcome rates associated with the use of this apparatus.[39,40,41]

The unresolved controversy regarding the on-site management of trauma patients is reflected in the regional variation of prehospital patient management protocols. This variation is observed profoundly in Canada, where the type of on-site care available to trauma patients ranges from BLS provided by emergency medical technician (EMTs) to physician-provided ALS. The type of prehospital care available to trauma patients is determined by regional policies that are dictated by local political, cultural, and economic factors as well as the influential opinion of local experts.

The purpose of the present study was to compare the effectiveness of three different approaches for the prehospital management of severely injured patients. The study assessed the relative effectiveness of a BLS-only approach, a physician-based ALS approach (MD-ALS), and a paramedic-based ALS system (PMD-ALS) used in three different Canadian cities.

Prehospital trauma care in Montreal is coordinated by Urgences-Santé, a nonprofit government agency under the aegis of the local health board. In this system, EMTs and physicians are used for the prehospital management of trauma patients, but only physicians are permitted to perform ALS. The protocol in effect at Urgences-Santé is aimed at limiting the request of a physician to cases of severe trauma. Before 1993, approximately 75% of the major trauma patients were treated at the scene by a physician. In 1994, this was reduced to 40%, in 1995 it was 30%, but since then it has been increased to 50%. The lack of availability of physicians to answer all of the requests creates a random fluctuation in which patients with severe injuries may receive on-site care by a physician with ALS available, or by an EMT applying the "scoop and run" approach.

Prehospital care in Quebec City is provided exclusively by EMTs administering BLS techniques only.

Prehospital care in Toronto is provided by EMTs who provide BLS and paramedics who are capable of performing ALS. Between 1984 and 1995 ambulance crews consisted of either two EMTs or two paramedics. Since that time, a two-tiered response algorithm was introduced in which the first responders were EMTs (BLS crew) followed by paramedics (ALS crews) who took over the care of the patient. To increase ALS coverage, in 1995, "split crews" were implemented. The ALS split crew consists of a fully certified paramedic and a level II paramedic who is not permitted to administer medications, initiate intravenous access, or perform endotracheal intubation. With this increased coverage, approximately 48% of the major trauma cases have on-site ALS available. The treatment performed by the paramedics (ALS crews) is subject to "off-line" control by written protocols and less frequently "on-line" control. BLS crews adhere to the "scoop and run" approach.

The objectives of the current study were threefold:

  • To compare the effectiveness of three different prehospital trauma care systems-one with only EMTs providing BLS and adhering to the "scoop and run" approach), one with paramedics available to provide on-site ALS (PMD-ALS), and the third with physicians available to provide on-site ALS (MD-ALS)-in reducing trauma-related mortality.

  • To evaluate and compare the effectiveness of three different types of on-site management (EMT-BLS, PMD-ALS, and MD-ALS) in reducing trauma-related mortality.

  • To evaluate and compare the effectiveness of two different types of on-site care (ALS and BLS) in reducing trauma-related mortality.

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