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Out-of-hospital endotracheal intubation in traumatic brain injury: Outcomes research provides us with an unexpected outcome

2004; Elsevier BV; Volume: 44; Issue: 5 Linguagem: Inglês

10.1016/j.annemergmed.2004.05.001

1097-6760

Brian J. Zink, Ronald F. Maio,

Airway Management and Intubation Techniques

In this issue of Annals, Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar provide an excellent example of classical outcomes research applied to the field of out-of-hospital care. Outcomes research in health care was catalyzed by the concern over rapidly rising health care costs. Politicians, administrators, and researchers wanted to determine which interventions and treatments were actually effective in real world settings.2.Lewin Group. The Outcome of Outcomes Research at AHCPR: Final Report. AHCPR Pub. No. 99-R044, 1999.Google Scholar, 3.Mendelson D.N. Goodman C.S. Ahn R. et al.Outcomes and effectiveness research in the private sector.Health Aff. 1998; 17: 75-90Crossref Scopus (16) Google Scholar One of the earliest assumptions of the field of outcomes research was that guidance for the practice of medicine could be obtained by the analysis of data routinely gathered in the process of delivering patients' care. Although the concept of outcomes research has greatly expanded, the secondary analysis of preexisting patient care databases still plays an important role, as is illustrated in this study by Wang et al. This article fulfills the broader description of current outcomes research in that it addresses a range of outcomes and the differences between the 2 groups through sophisticated risk adjustment using factors that may affect outcomes of interest.4.Garrison H.G. Spaite D.W. Maio R.F. et al.Emergency Medical Services Outcomes Project (EMSOP) III: The role of risk adjustment for out-of-hospital outcomes research.Ann Emerg Med. 2002; 40: 79-88Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar Furthermore, Wang et al address an area of out-of-hospital care—care of the major trauma patient—that has been identified as a priority in out-of-hospital outcomes research.5.Maio R.F. Garrison H.G. Spaite D.W. et al.Emergency Medical Services Outcomes Project I (EMSOP I): prioritizing conditions for outcomes research.Ann Emerg Med. 1999; 33: 423-432Abstract Full Text Full Text PDF PubMed Scopus (137) Google ScholarThe article by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar is the most recent in a flurry of investigations on out-of-hospital endotracheal intubation in patients with severe traumatic brain injury. After a 1997 study demonstrated improved survival in brain injury patients in whom out-of-hospital endotracheal intubation was accomplished, at least 3 subsequent studies have shown the opposite.6.Winchell R.J. Hoyt D.B. Endotracheal intubation in the field improves survival in patients with severe head injury.Arch Surg. 1997; 132: 592-597Crossref PubMed Scopus (295) Google Scholar, 7.Murray J.A. Demetriades D. Berne T.V. et al.Prehospital intubation in patients with severe head injury.J Trauma. 2000; 49: 1065-1070Crossref PubMed Scopus (164) Google Scholar, 8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google Scholar Wang et al now report the largest study of out-of-hospital tracheal intubation in patients with traumatic brain injury, and their results show a nearly fourfold adjusted odds of death in patients who had out-of-hospital endotracheal intubation compared with those who had emergency department (ED) endotracheal intubation. Out-of-hospital endotracheal intubation was also associated with worse neurologic outcomes.The accumulated weight of evidence from Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar and other recent studies6.Winchell R.J. Hoyt D.B. Endotracheal intubation in the field improves survival in patients with severe head injury.Arch Surg. 1997; 132: 592-597Crossref PubMed Scopus (295) Google Scholar, 7.Murray J.A. Demetriades D. Berne T.V. et al.Prehospital intubation in patients with severe head injury.J Trauma. 2000; 49: 1065-1070Crossref PubMed Scopus (164) Google Scholar, 8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google Scholar indicates that out-of-hospital endotracheal intubation of patients with severe traumatic brain injury is not helpful, and may be harmful. These findings fly in the face of our accepted ideas about the benefits of out-of-hospital airway management. Our first response is to look for methodologic or analysis flaws that prevented the investigators from finding the "correct" answer—that endotracheal intubation is beneficial in patients with traumatic brain injury. Indeed, the study by Wang et al can be criticized for using a static measure, the Abbreviated Injury Scale score, to define traumatic brain injury and for not using validated neurologic outcome measures for traumatic brain injury. The study compares patients receiving out-of-hospital endotracheal intubation with patients receiving endotracheal intubation in the ED but excludes those patients in the data set with a head/neck Abbreviated Injury Scale score of 3 or greater who were not intubated. Despite these shortcomings, Wang et al, with the largest series to date, consider and adjust well for potential confounding factors. They show that those patients who had out-of-hospital endotracheal intubation were more seriously injured than the patients who had endotracheal intubation in the ED, but use sophisticated statistical methods to control for this disparity, and still find that out-of-hospital endotracheal intubation was an independent predictor of increased mortality and poor neurologic outcome.Our next response is to think, "In our system, things would probably be different." Perhaps, but this study is more able to be generalized to the larger emergency medical services (EMS) world than previous studies of out-of-hospital intubation in traumatic brain injury because it is derived from the 2000 to 2002 Pennsylvania Trauma Outcome Study—a statewide trauma registry. The study by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar does suggest that not all out-of-hospital intubation is the same. Their data show that out-of-hospital endotracheal intubation performed by trained flight EMS providers using a rapid sequence intubation protocol was associated with decreased mortality and improved neurologic outcome. This suggests that there may be something in the technical expertise of the flight crew or in the airway management practices after intubation that has potent effects on outcome. For example, the Brain Trauma Foundation Guidelines for the Management of Severe Head Injury warn against the routine use of prophylactic hyperventilation.10.Brain Trauma Foundation. Guidelines for prehospital management of traumatic brain injury. Available at: http://www.braintrauma.org. Accessed May 5, 2004.Google Scholar Other studies have shown that out-of-hospital providers may inadvertently hyperventilate brain injury patients who are intubated.8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar Therefore, it is more complex than paramedics putting a tube in the trachea—other features of airway management and resuscitation may be part of the negative contribution of out-of-hospital care to traumatic brain injury outcome. When considering why aeromedical flight crew intubation with rapid sequence intubation may produce better outcomes in traumatic brain injury, there is the intriguing possibility that the induction agent used in a rapid sequence intubation protocol, administered early in the postinjury period, could be neuroprotective. However, studies in which paramedics used rapid sequence intubation (but not always an induction agent) to intubate patients with traumatic brain injury have found increased mortality in the intubated patients when compared with nonintubated or historical control patients.8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google ScholarOutcomes research is designed to detect associations from which investigators can draw inferences and generate hypotheses. This study of real world out-of-hospital care of patients with traumatic brain injury has demonstrated a strong association of out-of-hospital endotracheal intubation with worse outcome. In interpreting this work, Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar caution readers to remember that the findings do not show causality. But, if we were dealing with a drug that had such a negative association with patient outcomes, it would likely be pulled from the market. Unlike most out-of-hospital interventions, drugs are systematically and methodically prospectively tested through randomized controlled clinical trials.The current findings, along with the results from other recent studies, should compel us to aggressively investigate out-of-hospital intubation for severe traumatic brain injury. Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar note that "… a logical—but risky and controversial—direction would be to conduct a controlled clinical trial randomizing patients with traumatic brain injury to either out-of-hospital endotracheal intubation or no out-of-hospital endotracheal intubation."1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar We must ask, risk to whom? The mounting body of evidence suggests that out-of-hospital endotracheal intubation for patients with traumatic brain injury is not beneficial, and may be harmful. If our current out-of-hospital airway management protocols, or the training and supervision of our out-of-hospital providers results in worse outcomes for patients with traumatic brain injury, there is more "risk" with continuing business as usual than in performing definitive research in this area.Anyone who remembers the saga of the pneumatic antishock garment (MAST) as an out-of-hospital intervention can understand that if insufficient research is done before bringing an intervention to widespread use, then studies must be done ex post facto to definitively answer the question of efficacy. The research approach needed to provide a clear answer to this question in the case of out-of-hospital endotracheal intubation in patients with traumatic brain injury can be debated. Some may feel that quasi-experimental studies could answer the question, for example, by studying a large EMS system before and after out-of-hospital endotracheal intubation protocols were initiated. Others may feel that a prospective, randomized controlled trial of out-of-hospital intubation in traumatic brain injury is the only way we will be able to resolve this dilemma. Hopefully, the important outcomes research done by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar will stimulate randomized clinical trials or other investigations to determine whether some level of training, skill set, or specific airway management technique results in improved results in patients with traumatic brain injury. Patients with severe traumatic brain injury already have the deck stacked against them. If current out-of-hospital airway standards are dealing these patients a bum hand, we need to reshuffle the cards and take a fresh look. In this issue of Annals, Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar provide an excellent example of classical outcomes research applied to the field of out-of-hospital care. Outcomes research in health care was catalyzed by the concern over rapidly rising health care costs. Politicians, administrators, and researchers wanted to determine which interventions and treatments were actually effective in real world settings.2.Lewin Group. The Outcome of Outcomes Research at AHCPR: Final Report. AHCPR Pub. No. 99-R044, 1999.Google Scholar, 3.Mendelson D.N. Goodman C.S. Ahn R. et al.Outcomes and effectiveness research in the private sector.Health Aff. 1998; 17: 75-90Crossref Scopus (16) Google Scholar One of the earliest assumptions of the field of outcomes research was that guidance for the practice of medicine could be obtained by the analysis of data routinely gathered in the process of delivering patients' care. Although the concept of outcomes research has greatly expanded, the secondary analysis of preexisting patient care databases still plays an important role, as is illustrated in this study by Wang et al. This article fulfills the broader description of current outcomes research in that it addresses a range of outcomes and the differences between the 2 groups through sophisticated risk adjustment using factors that may affect outcomes of interest.4.Garrison H.G. Spaite D.W. Maio R.F. et al.Emergency Medical Services Outcomes Project (EMSOP) III: The role of risk adjustment for out-of-hospital outcomes research.Ann Emerg Med. 2002; 40: 79-88Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar Furthermore, Wang et al address an area of out-of-hospital care—care of the major trauma patient—that has been identified as a priority in out-of-hospital outcomes research.5.Maio R.F. Garrison H.G. Spaite D.W. et al.Emergency Medical Services Outcomes Project I (EMSOP I): prioritizing conditions for outcomes research.Ann Emerg Med. 1999; 33: 423-432Abstract Full Text Full Text PDF PubMed Scopus (137) Google Scholar The article by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar is the most recent in a flurry of investigations on out-of-hospital endotracheal intubation in patients with severe traumatic brain injury. After a 1997 study demonstrated improved survival in brain injury patients in whom out-of-hospital endotracheal intubation was accomplished, at least 3 subsequent studies have shown the opposite.6.Winchell R.J. Hoyt D.B. Endotracheal intubation in the field improves survival in patients with severe head injury.Arch Surg. 1997; 132: 592-597Crossref PubMed Scopus (295) Google Scholar, 7.Murray J.A. Demetriades D. Berne T.V. et al.Prehospital intubation in patients with severe head injury.J Trauma. 2000; 49: 1065-1070Crossref PubMed Scopus (164) Google Scholar, 8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google Scholar Wang et al now report the largest study of out-of-hospital tracheal intubation in patients with traumatic brain injury, and their results show a nearly fourfold adjusted odds of death in patients who had out-of-hospital endotracheal intubation compared with those who had emergency department (ED) endotracheal intubation. Out-of-hospital endotracheal intubation was also associated with worse neurologic outcomes. The accumulated weight of evidence from Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar and other recent studies6.Winchell R.J. Hoyt D.B. Endotracheal intubation in the field improves survival in patients with severe head injury.Arch Surg. 1997; 132: 592-597Crossref PubMed Scopus (295) Google Scholar, 7.Murray J.A. Demetriades D. Berne T.V. et al.Prehospital intubation in patients with severe head injury.J Trauma. 2000; 49: 1065-1070Crossref PubMed Scopus (164) Google Scholar, 8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google Scholar indicates that out-of-hospital endotracheal intubation of patients with severe traumatic brain injury is not helpful, and may be harmful. These findings fly in the face of our accepted ideas about the benefits of out-of-hospital airway management. Our first response is to look for methodologic or analysis flaws that prevented the investigators from finding the "correct" answer—that endotracheal intubation is beneficial in patients with traumatic brain injury. Indeed, the study by Wang et al can be criticized for using a static measure, the Abbreviated Injury Scale score, to define traumatic brain injury and for not using validated neurologic outcome measures for traumatic brain injury. The study compares patients receiving out-of-hospital endotracheal intubation with patients receiving endotracheal intubation in the ED but excludes those patients in the data set with a head/neck Abbreviated Injury Scale score of 3 or greater who were not intubated. Despite these shortcomings, Wang et al, with the largest series to date, consider and adjust well for potential confounding factors. They show that those patients who had out-of-hospital endotracheal intubation were more seriously injured than the patients who had endotracheal intubation in the ED, but use sophisticated statistical methods to control for this disparity, and still find that out-of-hospital endotracheal intubation was an independent predictor of increased mortality and poor neurologic outcome. Our next response is to think, "In our system, things would probably be different." Perhaps, but this study is more able to be generalized to the larger emergency medical services (EMS) world than previous studies of out-of-hospital intubation in traumatic brain injury because it is derived from the 2000 to 2002 Pennsylvania Trauma Outcome Study—a statewide trauma registry. The study by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar does suggest that not all out-of-hospital intubation is the same. Their data show that out-of-hospital endotracheal intubation performed by trained flight EMS providers using a rapid sequence intubation protocol was associated with decreased mortality and improved neurologic outcome. This suggests that there may be something in the technical expertise of the flight crew or in the airway management practices after intubation that has potent effects on outcome. For example, the Brain Trauma Foundation Guidelines for the Management of Severe Head Injury warn against the routine use of prophylactic hyperventilation.10.Brain Trauma Foundation. Guidelines for prehospital management of traumatic brain injury. Available at: http://www.braintrauma.org. Accessed May 5, 2004.Google Scholar Other studies have shown that out-of-hospital providers may inadvertently hyperventilate brain injury patients who are intubated.8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar Therefore, it is more complex than paramedics putting a tube in the trachea—other features of airway management and resuscitation may be part of the negative contribution of out-of-hospital care to traumatic brain injury outcome. When considering why aeromedical flight crew intubation with rapid sequence intubation may produce better outcomes in traumatic brain injury, there is the intriguing possibility that the induction agent used in a rapid sequence intubation protocol, administered early in the postinjury period, could be neuroprotective. However, studies in which paramedics used rapid sequence intubation (but not always an induction agent) to intubate patients with traumatic brain injury have found increased mortality in the intubated patients when compared with nonintubated or historical control patients.8.Davis D.P. Hoyt D.B. Ochs M. et al.The effect of paramedic rapid sequence intubation on outcome in patients with severe traumatic brain injury.J Trauma. 2003; 54: 444-453Crossref PubMed Scopus (278) Google Scholar, 9.Bochicchio G.V. Ilahi O. Joshi M. et al.Endotracheal intubation in the field does not improve outcome in trauma patients who present without an acutely lethal traumatic brain injury.J Trauma. 2003; 54: 307-311Crossref PubMed Scopus (181) Google Scholar Outcomes research is designed to detect associations from which investigators can draw inferences and generate hypotheses. This study of real world out-of-hospital care of patients with traumatic brain injury has demonstrated a strong association of out-of-hospital endotracheal intubation with worse outcome. In interpreting this work, Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar caution readers to remember that the findings do not show causality. But, if we were dealing with a drug that had such a negative association with patient outcomes, it would likely be pulled from the market. Unlike most out-of-hospital interventions, drugs are systematically and methodically prospectively tested through randomized controlled clinical trials. The current findings, along with the results from other recent studies, should compel us to aggressively investigate out-of-hospital intubation for severe traumatic brain injury. Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar note that "… a logical—but risky and controversial—direction would be to conduct a controlled clinical trial randomizing patients with traumatic brain injury to either out-of-hospital endotracheal intubation or no out-of-hospital endotracheal intubation."1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar We must ask, risk to whom? The mounting body of evidence suggests that out-of-hospital endotracheal intubation for patients with traumatic brain injury is not beneficial, and may be harmful. If our current out-of-hospital airway management protocols, or the training and supervision of our out-of-hospital providers results in worse outcomes for patients with traumatic brain injury, there is more "risk" with continuing business as usual than in performing definitive research in this area. Anyone who remembers the saga of the pneumatic antishock garment (MAST) as an out-of-hospital intervention can understand that if insufficient research is done before bringing an intervention to widespread use, then studies must be done ex post facto to definitively answer the question of efficacy. The research approach needed to provide a clear answer to this question in the case of out-of-hospital endotracheal intubation in patients with traumatic brain injury can be debated. Some may feel that quasi-experimental studies could answer the question, for example, by studying a large EMS system before and after out-of-hospital endotracheal intubation protocols were initiated. Others may feel that a prospective, randomized controlled trial of out-of-hospital intubation in traumatic brain injury is the only way we will be able to resolve this dilemma. Hopefully, the important outcomes research done by Wang et al1.Wang H.E. Peitzman A.B. Cassidy L.D. et al.Out-of hospital endotracheal intubation and outcome after traumatic brain injury.Ann Emerg Med. 2004; 44: 439-450Abstract Full Text Full Text PDF PubMed Scopus (218) Google Scholar will stimulate randomized clinical trials or other investigations to determine whether some level of training, skill set, or specific airway management technique results in improved results in patients with traumatic brain injury. Patients with severe traumatic brain injury already have the deck stacked against them. If current out-of-hospital airway standards are dealing these patients a bum hand, we need to reshuffle the cards and take a fresh look.