(Table 24) summarizes the results of a multiple logistic regression used to test the association between the risk of mortality and the phase of regionalization while adjusting for Injury Severity Score and patient age. A number of other models that included mechanism of injury and body region injured as covariates were tested. These more complex models did not produce a significant improvement in the validity, as assessed by the goodness-of-fit statistic. The simpler model, therefore, was retained. The results of this analysis showed that after adjusting for patient age and Injury Severity Score, the process of regionalization produced significant reductions in the risk of mortality. More specifically, compared with the preimplementation period, the adjusted relative odds of dying were 0.39, 0.18, and 0.15 during the initiation, intermediate, and advanced phases, respectively. These estimates are both clinically and statistically (p < 0.001) significant.
The data in Table 25 summarize the results of the multiple logistic regression models evaluating the adjusted association between prehospital time, the trauma center classification, the time to admission, and the method of arrival of the patient to the trauma center (transfer or direct transport). The data show that the relative odds of dying associated with being treated at a tertiary center compared with a secondary center was 0.46. The relative odds of dying associated with being treated at a tertiary center compared with a primary center was 0.25. These data also show that the odds ratio of dying associated with being transferred compared with being transported directly to a secondary or tertiary trauma center was 1.29. Furthermore, although the odds ratio for prehospital time was clinically and statistically significant (p < 0.001), the odds ratio for time to admission was not clinically important or statistically significant (p > 0.05).
A third model was tested in which the variable representing the phase of regionalization was added to those already in the model: prehospital time, trauma center designation, time to admission, and method of arrival at the trauma center. The purpose of testing this model was to estimate the proportion of the variance explained by the regionalization phase that was captured by the variables describing the components of a trauma care system that were included in the second model. The result of this analysis showed that more than 53% of the variance explained by the variable describing the phase of regionalization was attributable to reduction in prehospital time, the trauma center designation, and the method of arrival of the patient at the trauma center (Table 21).
This was a prospective cohort study that evaluated the impact of the changes in the trauma care system of Quebec, a Canadian province, on the mortality among patients with major trauma. The study followed the Quebec trauma care system from before to 5 years after the implementation of regionalization. The phases of regionalization were identified by specific landmarks that clearly defined the process of integration of the trauma care services in the province in one system and network. The target population of the study was that of patients with major trauma. The sample was selected after a comprehensive review of all records of patients treated for injuries at the acute-care hospitals of Montreal and Quebec City. The restriction of the sample selection process to these two cities is appropriate for two reasons: first, because these are the two largest urban areas of the province, and second, because the changes in trauma care regionalization were implemented in these locations.
The results of the study demonstrated that since the implementation of the regionalized system, the mortality in major trauma patients was significantly reduced. This reduction in mortality was observed during the initial, the intermediate, and the advanced phases of the regionalization process. It is important to note that the mortality rate continued to decline during each phase and for the entire 5-year period after the introduction of regionalization that was covered by the current study. This decline in mortality remained statistically and clinically significant after adjusting for all potential confounding variables, including patient age and injury severity measures.
The first important component of a trauma care system is the establishment, designation, and support of tertiary trauma centers as the hospitals where patients with severe trauma should be treated. The second important component of a trauma care system is efficient prehospital care, characterized by a short interval between the time of injury and definitive in-hospital care, and by accurate identification and triage of patients with major trauma to tertiary trauma centers. The importance of these components has been generally accepted from a conceptual and a theoretical perspective and has been demonstrated in a limited number of studies. [1,2,30-32] To date, however, the direct relationship between these two components of trauma care systems and reduced mortality has not been empirically demonstrated.
The data from this study showed that during the evolution of the Quebec trauma care system toward regionalization, the prehospital time and the time to definitive care, defined as the time to admission, intensive care treatment, or surgery, were reduced at levels that were both clinically important and statistically significant. In addition, the proportion of patients with major trauma who were treated at tertiary trauma centers was increased. The data also showed that both the prehospital time and the trauma center designation of the treating hospital were important predictors of mortality in this sample of patients with major trauma. More specifically, the risk of mortality increased significantly with longer prehospital times, whereas the mortality risk was lower for tertiary trauma centers compared with secondary and primary trauma centers. These results, therefore, have shown that during the implementation of the regionalized Quebec trauma care system, the two important components of trauma care described above changed significantly and in the appropriate direction and that these changes were associated with significant reductions in trauma-related mortality. Taken collectively, these results have provided empirical evidence that the process of trauma care regionalization, defined as the establishment of trauma centers and of prehospital care aimed at prompt transport of severely injured patients to the appropriate hospital, produces significant benefits by reducing trauma-related mortality. This process-outcome association has been demonstrated in a single system that has been followed during the first 5 years of regionalized trauma care while controlling for the effect of all potential confounding factors.
The results of the stratified analysis showed that implementation of regionalization produced significant reductions in the mortality rates among patients with moderate and major injuries, although the impact on patients with fatal injuries was modest. This is consistent with the principles established by Trunkey stating that the most important impact of trauma care will be realized in the group of patients who have major life-threatening injuries.  In these patients, mortality will be reduced if appropriate treatment is provided with minimal delay at tertiary (Level I) trauma centers. In addition, the probability of dying among patients with fatal injuries remains high and in general is not affected by the level of trauma care available.
One of the important observations of the current study was that the time interval from arrival of the patient to the hospital to initiation of definitive care was significantly reduced in the tertiary trauma centers during the process of regionalization. This parameter did not change significantly for the secondary or primary centers. These results may suggest that the reduction in mortality in the tertiary centers may be partially explained by the reduced delay to definitive care. It is equally important to note that the time to definitive care was not lower for the tertiary centers compared with the primary and secondary centers. This observation may suggest that the quality of care available at the tertiary centers may compensate for the longer delays. Nevertheless, this observation also suggests that the emergency rooms of the tertiary centers may be becoming saturated because of the volume of patients and the severity of injuries. In view of this finding, interventions that are aimed at minimizing this saturation should be considered to ensure that these facilities continue to function at their full potential.
The results of the multiple logistic regression models showed that both the prehospital time and the designation level of the treating hospital were independently and significantly associated with the risk of dying. These analyses showed that for every additional minute of prehospital time, the risk of dying increased by 5%. Extrapolation allows us to estimate that the adjusted risk of dying increases by 57% (odds ratio, 1.57), for every 10-minute increase in prehospital time. During the time period covered by the study, the total prehospital time was reduced by an average of 18 minutes. This represents a decrease in the adjusted risk of dying by a factor of 2.25 (odds ratio, 0.44). With respect to the trauma care designation of the treating hospital, the logistic regression models showed that after adjusting for all potential confounders, the risk of dying in tertiary trauma centers was 54% lower than in secondary centers and 75% lower than in primary centers. This is an extremely important observation that further confirms the axiom that patients with major trauma should be treated at tertiary trauma centers. The logistic regression analyses also showed that patients who were transferred to a trauma center had a 30% increase in mortality risk compared with patients who were transported directly from the scene to a trauma center. In the logistic regression models, time to definitive care was not significantly associated with the risk of mortality. This observation suggests that the quality of care of the treating hospital and reduced prehospital times are more important than delays after arrival at the hospital. It is also quite possible that the deleterious effect of long delays to definitive care may be confounded by the designation of trauma centers, because this parameter was significantly reduced in tertiary trauma centers. It is also possible that in tertiary trauma centers patients with severe injuries are properly and promptly triaged after arrival at the hospital, thus reducing the delay to definitive care for this high-risk group. Conversely, in the tertiary centers, patients with less severe injuries that do not require immediate attention may have longer waiting times to definitive care. The increased volume of patients with such injuries may explain the higher delay to definitive care but reduced mortality in tertiary centers.
The final logistic regression model showed that the changes in prehospital time, trauma center designation, method of arrival of the patient to the trauma center, and time to definitive care explain more than 50% of the variance in mortality captured by the process of regionalization of trauma care. This is an important observation because it provides direct evidence that these components of a trauma care system are the major factors contributing to its effectiveness in reducing mortality. This observation also suggests that a proportion of the effect of trauma care regionalization may not be explained by changes in these components of the system. Other factors may contribute to the effectiveness of trauma care regionalization in Quebec that are not captured by these variables because they are more universal in nature. These factors may be changes in prehospital care, increased awareness and education regarding the management of trauma patients at all acute-care hospitals, and improved technology that has become available to all trauma hospitals during the period covered by the study. In addition, it should be pointed out that from a statistical viewpoint, explanation of more than 50% of the variance in the outcome variable is rare, indicating an extremely large effect size.
The strengths of the present study include its prospective design and the large sample size that ensured sufficient power to conduct important subgroup comparisons and analysis with reliable and valid results. The study followed without interruption the evolution of the Quebec trauma care system from before implementation to the advanced stages of regionalization. The data were collected from all acute-care hospitals that treated trauma patients from the two urban areas where regionalization was introduced. The comprehensive coverage of patient types and hospitals eliminates any selection bias. Data were available on all potential confounders, and statistical analyses were used to control their effects on the study results.
The current study produced direct empirical evidence to support the benefits of an integrated regionalized trauma care system. The independent benefits of tertiary trauma centers and reduced prehospital time were also clearly demonstrated. The results are compatible with those that have been reported previously in the literature. The current study, however, has used data from a single region to demonstrate the process-outcome relationship of trauma care regionalization. Other authors have supported this relationship based on theoretical concepts and the accumulation of evidence from a number of studies, each one evaluating a specific component of the trauma care system.
The conclusions of the present study are the following. First, trauma care regionalization produces significant reductions in the mortality of patients with major trauma. Second, the designation of tertiary trauma centers where patients with severe injuries should be treated and reduced prehospital times are both essential if these benefits are to be realized. Further research should be conducted that will compare different models of trauma care systems and that will identify other components of trauma care that could be improved. The impact of trauma care systems on patient outcomes other than mortality, including disability, morbidity, and quality of life, should be evaluated. Finally, there is an immediate need for a complete economic evaluation that will include cost-effectiveness assessments of trauma care systems.
Dr. A. Brent Eastman (La Jolla, California): Dr. Sampalis and his colleagues in Montreal are to be doubly congratulated, for not only presenting a very important paper, but for the establishment of a trauma system in the province of Quebec. Dr. Mulder particularly was instrumental in the development and evolution of this trauma system.
The authors had the foresight to plan and initiate a prospective cohort study coincident with the creation of this trauma system. This was done for the express purpose of proving the relationship between certain components of their trauma system and a decrease in mortality rate. They have succeeded by documenting a threefold decrease, 52 to 18%, in the mortality rate of trauma patients.
As with many comprehensive studies, this study raises more questions than it answers. You present this as an analysis of the Quebec Regionalized Trauma System, and yet the study sample is clearly "patients admitted to the acute-care hospitals in Montreal and Quebec City," not the entire province. Since one of the principal components examined was prehospital times, it is critical to know what effect travel distances and weather conditions had on this component.
You do not specifically address such factors as prehospital airway control. Was there any change in prehospital intubation protocols during this study period? The mortality related to prolonged prehospital times may be related to airway problems, and if the treatment of this was improved during the study period, that may also have contributed to improved survival.
You make reference to overall increased survival when major trauma patients are taken expeditiously to designated tertiary hospitals. However, you did not specifically define if there was a decrease in mortality rates in these tertiary hospitals per se after implementation of the system. For example, did the survival rate increase at McGill University after implementation of the system?
One of the most pressing questions in the U.S. today is the relationship between volume, either surgeon or center, and outcome. This is being specifically addressed in the current version of the ACSCOT document for optimal care of the injured patient. Your database may provide some answers on this critical question. Did your tertiary centers realize an increased volume with regionalization, and was this a factor in improved survival rates?
One of the perennial problems in studying the issue of prehospital triage has been the absence of data from nontrauma hospitals, therefore the lack of a denominator. I understand from personal communications with your coauthor, Dr. Mulder, that with your single-payer system you've been able to tie hospital reimbursement to the provision of trauma data and that you do have data from all acute-care hospitals. With those data, you will be able to accurately determine the sensitivity and specificity of your prehospital triage instrument.
Given the importance that most of the trauma world places on the efficacy of the ATLS, it was notable that you do not mention it in your manuscript. You found an increase in ISS, motor vehicle crashes, and injuries to the head, thorax, and abdomen. This seems counterintuitive, given the increased use of seat belts, airbags, and drunk-driving prevention efforts. Can you explain?
I'm interested that you did not see a significant change in survival of the most severely injured patients. Many systems have found this subset to be where the greatest improvement was found.
This important paper will be frequently quoted and will provide powerful information for those attempting to overcome the political and economic barriers to creating much-needed trauma systems. I would close by asking two questions. Do your data provide evidence that outcome is improved with increased volume? And two, is prevention an essential element of your system? Only prevention will address the immediate deaths that you, in your manuscript, call nonpreventable. I would submit that these immediate deaths represent the greatest opportunity for prevention. I thank the Association and the authors for the opportunity of discussing this important paper.
Dr. Ari K. Leppaniemi (Helsinki, Finland): Finland doesn't have any certified trauma centers at the moment, and we need to review our trauma care system. My question is, since the size of Finland is about the same as Quebec is with a little smaller population, are four tertiary trauma centers for 8 million people in that land area sufficient, or should there be maybe less?
Dr. William B. Long (Portland, Oregon): The Oregon trauma system has been operational for 10 years, but we still have problems with the Oregon Trauma Register getting completeness of data. In fact, until this year, we had 35% missing data from the rural hospital Level IIIs and IVs. I would be interested to know what percentage of your Levels IIs, IIIs and IVs in Quebec were contributing data and how complete it was. Thank you.
Dr. Richard J. Mullins (Portland, Oregon): Are patients with head injury the group that seems to have benefited the most from implementation of the trauma system in Quebec? If that is the case, Dr. Sampalis, do you have an opinion what are the specific reasons why head-injured patients have an improved outcome when they are treated in a trauma system?
Dr. Lawrence H. Pitts (San Francisco, California): Dr. Sampalis, you mentioned that the number of secondary centers had fallen slightly as the various periods went on, and that this was better matched to population. How was that reduction achieved? Was it voluntary cessation of care by some of the centers, or was that induced by some other method?
Dr. John S. Sampalis (closing): Thank you very much for the questions. I'm going to try to be brief. With respect to the comments raised by Dr. Eastman regarding prehospital travel time and prehospital care, I have to mention that in Quebec the situation with respect to prehospital trauma care is quite different than what exists in the United States.
We have two types of trauma care: one that's available in Montreal, where physicians may be dispatched to the scene to provide Advanced Life Support; and the other kind of prehospital care that we have is essentially what we hope is right now scoop-and-run, which is Basic Life Support provided by emergency medical technicians. Therefore, airway management at the scene is restricted to a small number of patients that are treated by physicians in Montreal.
I'm not sure whether we are observing a circular trend in hospitals doing better overall. I think that's an interesting question. However, if I am to try and assess what is happening with respect to our trauma patients, I think that in fact we are treating these patients better.
This is a study that has followed the series of other studies where we first showed that, in fact, in the tertiary trauma centers after designation, the mortality was reduced. Therefore, it follows from these other studies that we are actually treating trauma patients better in the entire system.
Did tertiary trauma centers realize an increase in volume? I think this is accurate to say, as we can see by the increase in the proportion of patients with major trauma that were treated at these institutions.
I did not mention ATLS, and that's a very important point. However, from what I understand from our system, most of the surgeons practicing in tertiary trauma centers have taken this training.
The point that there has been an increase in motor vehicle collisions might be counterintuitive given the existence of preventive measures and airbags and seat belts, etc. However, the fact that motor vehicle accidents do occur has nothing to do with the availability of a seat belt or airbag. Therefore, these patients continue to come to us. In fact, we have seen an increase, a change in the profile of trauma in our population, with a younger population, more and more vehicle accidents, and more violent crimes.
Do the data provide evidence that the outcome has improved in the entire system? I think so. And the fact that we use data from only Montreal and Quebec City is explained by the point that these are the two major cities in the province. This is where most trauma patients are being treated, and the implementation of the trauma care system at this point in time focused on these two cities. Therefore, I wanted to see what was happening in these two regions before starting to compare the rest of the province.
I think the next phase of studies that we will do with the expansion of the network to the entire province will evaluate the impact on the other hospitals. Are four tertiary trauma centers necessary or enough for 8 million inhabitants? I'm not sure whether I can answer this right now. This is probably an administrative question that we will have to address very soon in the province.
Completeness of data. That's a very important point. I should mention that we didn't only rely on the Trauma Registry, but this study was also funded by the government of Canada. Therefore, any data that we were missing in the registry, we went and captured from the hospital charts. We included patients that we had most of the information available that we needed.
Are patients with head trauma doing better? I assume they are, and that's a very important point that we need to conduct a subanalysis.
Why were the number of secondary centers reduced? This was done by a Committee of Trauma Care in the province that evaluated the performance of these centers and the need to have them within the network. It was decided that they weren't necessary, given their situation and the volume of patients that they treated. This volume of patients now would go to the other secondary and the tertiary centers. Thank you very much for the discussion and the privilege of presenting the paper.
1. Trunkey DD. Trauma. Sci Am. 1983;249(2):28-35.
2. Gold E. Trauma care regionalization: a necessity. J Trauma. 1983;23:260-262.
3. Maull KI, Haynes BW Jr. The integrated trauma service concept. JACEP. 1977;6:497-499.
4. West JG, Trunkey DD, Lim RC. Systems of trauma care. Arch Surg. 1979;114:455-460.
5. American College of Emergency Physicians. Guidelines for trauma care systems. Ann Emerg Med. 1987;16:459-463.
6. Cales RH, Trunkey DD. Preventable trauma deaths: a review of trauma care systems development. JAMA. 1985;254:1059-1063.
7. Kreis DJ Jr, Plasencia G, Augenstein D. Preventable trauma deaths: Dade County, Florida. J Trauma. 1988;26:649-654.
8. Lowe DK, Gately HL, Goss JR, Frey CL, Peterson CB. Patterns of deaths, complication, and error in the management of motor vehicle accident victims: implications for a regional system of trauma care. J Trauma. 1983;23:503-509.
9. Dykes EH, Spence LJ, Bohn DJ, Wesson DE. Evaluation of pediatric trauma care in Ontario. J Trauma. 1989;29:724-729.
10. Boyd DR, Cowley RA. Comprehensive regional trauma/emergency medical services (EMS) delivery systems: the United States experience. World J Surg. 1983;7:149-157.
11. Cales RH, Anderson PG, Heilig RW Jr. Utilization of medical care in Orange County: the effect of implementation of a regional trauma system. Ann Emerg Med. 1985;14:853-858.
12. Klauber MR, Marshall LF, Toole BM, Knowlton SL, Bower SA. Cause of decline in head-injury mortality rate in San Diego County, California. J Neurosurg. 1985;62:528-531.
13. Shackford SR, Hollingworth-Fridlund P, Cooper GF, Eastman AB. The effect of regionalization upon the quality of trauma care as assessed by concurrent audit before and after institution of a trauma system: a preliminary report. J Trauma. 1986;26:812-820.
14. Shackford ST, Mackersie RC, Hoyt DB, et al. Impact of a trauma system on outcome of severely injured patients. Arch Surg. 1987;122:523-527.
15. Bazzoli GJ, Madura KJ, Cooper GF, MacKenzie EJ, Maier RV. Progress in the development of trauma systems in the United States: results of a national survey. JAMA. 1995;273:395-401.
16. Mullins RJ, Veum-Stone J, Helfand M, et al. Outcome of hospitalized injured patients after institution of a trauma system in an urban area. JAMA. 1994;271:1919-1924.
17. Hulka F, Mullins RJ, Mann NC. Influence of a statewide trauma system on pediatric hospitalization and outcome. J Trauma. 1997;42:514-519.
18. Stewart TC, Lane PL, Stefantis T. An evaluation of patient outcomes before and after trauma center designation using Trauma and Injury Severity Score analysis. J Trauma. 1995;39:1036-1040.
19. Dove DB, Stahl WM, DelGuercio LRM. A five-year review of deaths following urban trauma. J Trauma. 1980;20:760-766.
20. Hackey RB. The politics of trauma system development. J Trauma. 1995;39:1045-1053.
21. Mullins RJ, Veum-Stone J, Hedges JR, et al. Influence of a statewide trauma system on location of hospitalization and outcome of injured patients. J Trauma. 1996;40:536-546.
22. Bazzoli GJ, MacKenzie EJ. Trauma centers in the United States: identification and examination of key characteristics. J Trauma. 1995;38:103-110.
23. Zimmer-Gembeck MJ, Southard PA, Hedges JR, et al. Triage in an established trauma system. J Trauma. 1995;39:922-928.
24. National Trauma Registry Comprehensive Data Set Survey Results (Annual Report). Canadian Institute for Health Information; September 1997.
25. National Trauma Registry Annual Report. Canadian Institute for Health Information; January 1998.
26. National Trauma Registry Comprehensive Data Set Survey Results, Raw Data and Cross Tabulations (Annual Report). Canadian Institute for Health Information; September 1997.
27. Sampalis JS, Lavoie A, Williams JI, Mulder DS, Kalina M. Standardized mortality ratio analysis on a sample of severely injured patients from a large Canadian city without regionalized trauma care. J Trauma. 1992;33:205-212.
28. Sampalis JS, Lavoie A, Williams JI, Mulder DS, Kalina M. Impact of on-site care, prehospital time, and level of in-hospital care on survival in severely injured patients. J Trauma. 1993;34:252-261.
29. Gervin AS, Fischer RP. The importance of prompt transport in salvage of patients with penetrating heart wounds. J Trauma. 1982;22:443-448.
30. Sampalis JS, Lavoie A, Boukas S, et al. Trauma centre designation: initial impact on trauma-related mortality. J Trauma. 1995;39:232-239.
31. Sampalis JS, Denis R, Frechette P, Fleizer D, Brown R, Mulder D. Direct transport to tertiary trauma centre versus transfer from lower level facilities: impact on mortality among patients with major trauma. J Trauma. 1997;43:288-296.
© 1999 Lippincott Williams & Wilkins, Inc.
32. Sloan EP, Callahan EP, Duda J, Sheatt C, Robin A, Barrett J. The effect of urban trauma system hospital bypass on prehospital transport times and level 1 trauma patient survival. Ann Emerg Med. 1989;18:1146-1150.