Advanced Cardiac Life Support
http://www.100md.com
《新英格兰医药杂志》
To the Editor: Although Stiell and colleagues (Aug. 12 issue)1 state that the Ontario Prehospital Advanced Life Support (OPALS) Study found no improvement in the rate of survival among patients with out-of-hospital cardiac arrest as a result of the addition of "advanced life support" interventions provided by paramedics (and Callans concurred in the accompanying Perspective article),2 these findings cannot be generalized to all emergency-medical-services systems. The authors suggest that definitive care is "advanced life support." I would submit that definitive care must be viewed as definitive therapy for a patient's underlying conditions. Myocardial infarction is a common cause of cardiac arrest. Definitive therapy includes thrombolysis and cardiac catheterization. In this regard, "advanced life support," as described in the present study, is supportive therapy, not definitive. The findings of this study should therefore be generalized only to emergency-medical-services systems in which paramedics provide advanced life support until the patient's admission to an emergency department, where the decisions are made regarding sending patients further to sites of definitive care. The findings cannot be generalized to systems in which physicians provide prehospital care that includes thrombolysis with direct admission to a coronary care unit or direct admission to cardiac catheterization facilities (in both cases, bypassing the emergency department), as occurs in many parts of Europe.
Michael Nurok, M.B., Ch.B.
Brigham and Women's Hospital
Boston, MA 02115
mnurok@partners.org
References
Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351:647-656.
Callans DJ. Out-of-hospital cardiac arrest -- the solution is shocking. N Engl J Med 2004;351:632-634.
Dr. Stiell replies: We suspect that Dr. Nurok misunderstands the group of patients that we studied. Our study did not address patients with myocardial infarction but, rather, those with out-of-hospital cardiac arrest. Regardless of the particular country or the particular emergency-medical-services organization, most such patients, who receive ongoing cardiopulmonary resuscitation, are too unstable even to undergo echocardiogram studies, let alone be taken to the coronary care unit or catheterization laboratory or to receive thrombolytic agents. We have seen no data that suggest that patients with out-of-hospital cardiac arrest have better outcomes in Europe.
Ian G. Stiell, M.D.
University of Ottawa
Ottawa, ON K1Y 4E9, Canada
istiell@ohri.ca
for the OPALS Study Group
Dr. Callans replies: The authors of the OPALS Study refer to advanced life support as definitive care only with reference to comments in previous publications.1 They did not imply that additional therapy would not benefit selected patients with out-of-hospital cardiac arrest. They found that, in their specific community, training paramedics to perform endotracheal intubation and to deliver intravenous medications did not significantly improve outcome.
The issue of thrombolytic therapy for cardiac arrest is certainly worth further study. Several nonrandomized studies have suggested a significant benefit of out-of-hospital thrombolytic therapy even after prolonged resuscitation efforts2,3; however, the possibility of selection bias cannot be refuted by the available data.
There is nothing in the OPALS Study that suggests that future improvements in resuscitation techniques should not be avidly sought. Instead, the message is that, in a world of limited resources, determining the incremental benefit of each therapy is prudent.
David J. Callans, M.D.
University of Pennsylvania School of Medicine
Philadelphia, PA 19104
david.callans@uphs.upenn.edu
References
Eisenberg MS, Bergner L, Hallstrom A. Cardiac resuscitation in the community: importance of rapid provision and implications for program planning. JAMA 1979;241:1905-1907.
Lederer W, Lichtenberger C, Pechlaner C, Kroesen G, Baubin M. Recombinant tissue plasminogen activator during cardiopulmonary resuscitation in 108 patients with out-of-hospital cardiac arrest. Resuscitation 2001;50:71-76.
B?ttiger BW, Bode C, Kern S, et al. Efficacy and safety of thrombolytic therapy after initially unsuccessful cardiopulmonary resuscitation: a prospective clinical trial. Lancet 2001;357:1583-1585.
Michael Nurok, M.B., Ch.B.
Brigham and Women's Hospital
Boston, MA 02115
mnurok@partners.org
References
Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351:647-656.
Callans DJ. Out-of-hospital cardiac arrest -- the solution is shocking. N Engl J Med 2004;351:632-634.
Dr. Stiell replies: We suspect that Dr. Nurok misunderstands the group of patients that we studied. Our study did not address patients with myocardial infarction but, rather, those with out-of-hospital cardiac arrest. Regardless of the particular country or the particular emergency-medical-services organization, most such patients, who receive ongoing cardiopulmonary resuscitation, are too unstable even to undergo echocardiogram studies, let alone be taken to the coronary care unit or catheterization laboratory or to receive thrombolytic agents. We have seen no data that suggest that patients with out-of-hospital cardiac arrest have better outcomes in Europe.
Ian G. Stiell, M.D.
University of Ottawa
Ottawa, ON K1Y 4E9, Canada
istiell@ohri.ca
for the OPALS Study Group
Dr. Callans replies: The authors of the OPALS Study refer to advanced life support as definitive care only with reference to comments in previous publications.1 They did not imply that additional therapy would not benefit selected patients with out-of-hospital cardiac arrest. They found that, in their specific community, training paramedics to perform endotracheal intubation and to deliver intravenous medications did not significantly improve outcome.
The issue of thrombolytic therapy for cardiac arrest is certainly worth further study. Several nonrandomized studies have suggested a significant benefit of out-of-hospital thrombolytic therapy even after prolonged resuscitation efforts2,3; however, the possibility of selection bias cannot be refuted by the available data.
There is nothing in the OPALS Study that suggests that future improvements in resuscitation techniques should not be avidly sought. Instead, the message is that, in a world of limited resources, determining the incremental benefit of each therapy is prudent.
David J. Callans, M.D.
University of Pennsylvania School of Medicine
Philadelphia, PA 19104
david.callans@uphs.upenn.edu
References
Eisenberg MS, Bergner L, Hallstrom A. Cardiac resuscitation in the community: importance of rapid provision and implications for program planning. JAMA 1979;241:1905-1907.
Lederer W, Lichtenberger C, Pechlaner C, Kroesen G, Baubin M. Recombinant tissue plasminogen activator during cardiopulmonary resuscitation in 108 patients with out-of-hospital cardiac arrest. Resuscitation 2001;50:71-76.
B?ttiger BW, Bode C, Kern S, et al. Efficacy and safety of thrombolytic therapy after initially unsuccessful cardiopulmonary resuscitation: a prospective clinical trial. Lancet 2001;357:1583-1585.