Termination of Resuscitation in Out-of-Hospital Cardiac Arrest
http://www.100md.com
《新英格兰医药杂志》
To the Editor: We do not believe that Morrison et al. (Aug. 3 issue)1 focused on the right question in the Termination of Resuscitation (TOR) trial. If saving lives is the issue, the question is: What can early, adequate advanced cardiac life support achieve? Basic life support — as provided in this study — will never result in "good" cardiopulmonary resuscitation, and transportation of the patient to the emergency department during basic life support is thus futile. With physician-staffed advanced cardiac life support systems, 40 to 50% of patients with out-of-hospital cardiac arrest have a return of spontaneous circulation, and 10 to 15% survive with good neurologic outcomes.2,3,4 In the study reported by Morrison and colleagues, the rates of return of spontaneous circulation and hospital discharge were substantially lower — by a factor of 10 and 5, respectively — than those associated with physician-staffed systems.1 Thus, implementation of the proposed rule may result in Russian roulette for patients with out-of-hospital cardiac arrest.
Would anyone ask about survival after motor vehicle accidents involving patients without safety belts in their cars? Why not just use cars with safety belts, even if doing so is more expensive? Let's think differently and send the advanced cardiac life support know-how of the emergency department — that is, experienced physicians — to our patients undergoing out-of-hospital cardiac arrest. Education and organization, not termination, make the difference.2,3,4
Bernd W. B?ttiger, M.D.
Erik Popp, M.D.
Peter Teschendorf, M.D.
University of Heidelberg
D-69120 Heidelberg, Germany
bernd.boettiger@med.uni-heidelberg.de
References
Morrison LJ, Visentin LM, Kiss A, et al. Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest. N Engl J Med 2006;355:478-487.
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.
B?ttiger BW, Grabner C, Bauer H, et al. Long term outcome after out-of-hospital cardiac arrest with physician staffed emergency medical services: the Utstein style applied to a midsized urban/suburban area. Heart 1999;82:674-679.
Fischer M, Krep H, Wierich D, et al. Comparison of the emergency medical services systems of Birmingham and Bonn: process efficacy and cost effectiveness. Anasthesiol Intensivmed Notfallmed Schmerzther 2003;38:630-642.
To the Editor: The investigators in the TOR trial address one important aspect of cardiac resuscitation: When does survival become so unlikely that it does not merit further treatment? They do not directly address a more difficult question: When does the risk exceed the benefit? The primary risk of cardiac resuscitation is not death (which would occur without treatment) but rather survival with a disability that the patient would view as being worse than death. Even category I cerebral performance may not be normal, and many survivors have significant neurologic injury.
Several years ago, a colleague and I surveyed providers who performed cardiac resuscitation on a regular basis, and most of them wanted their own resuscitation to be stopped shortly after the first attempts at defibrillation.1 It is difficult to determine how long a cardiac resuscitation attempt should continue, but it is clear that the current practice of continuing until there is essentially no hope of survival poses difficult ethical questions.
Mark Hauswald, M.D.
University of New Mexico
Albuquerque, NM 87107
mhauswald@salud.unm.edu
References
Hauswald M, Tanberg D. Out-of-hospital resuscitation preferences of emergency health care workers. Am J Emerg Med 1993;11:221-224.
To the Editor: Morrison et al. attempted to validate a three-part clinical prediction rule for the termination of basic life support resuscitative efforts during out-of-hospital cardiac arrests. The study, however, has several limitations. First, although the data were analyzed prospectively, this was not a consecutive series of patients, since site-specific enrollment ranged from 21 to 100% of all eligible patients. Second, the reasons for variable site recruitment rates are not disclosed; a potential selection bias exists for patients at higher risk for death, which would favor the prediction rule. Finally, the authors should disclose the identified clinical variables (including the type of cardiac arrest) that were associated with survival until hospital discharge. Therefore, we suggest that these rules should be minimal requirements but that they should not override clinical judgment in determining when enough is enough.
Andrew E. Ajani, M.B., M.D.
Royal Melbourne Hospital
Melbourne 3050, Australia
Ron Waksman, M.D.
Washington Hospital Center
Washington, DC 20010
ron.waksman@medstar.net
To the Editor: The study conducted by Morrison et al. to validate a rule for terminating basic life support resuscitation in out-of-hospital cardiac arrest defined the test characteristics incorrectly. The definition of a positive "test" should be the decision to transport the patient to an emergency department (rather than the decision to terminate basic life support resuscitative efforts) and the "disease" should be survival (the preferred outcome for the patient, rather than death). With the use of this schema, the sensitivity of the transport decision with the rule is 90.2%, and the specificity is 64.4% — the reverse of the figures reported by Morrison and colleagues. With the use of their methods, the positive likelihood ratio (the sensitivity of the rule recommending the termination of basic life support resuscitative efforts, divided by 1 minus the specificity of the rule recommending termination) is 6.6 (95% confidence interval , 2.60 to 16.76), and the negative likelihood ratio (1 minus the sensitivity of the rule recommending transportation to an emergency department and continuation of basic life support resuscitative efforts, divided by the specificity of the rule recommending transportation) is 0.39 (95% CI, 0.35 to 0.45). With the use of the more intuitively correct numbers in Table 1, the positive likelihood ratio is 2.53 (95% CI, 2.23 to 2.87), and the negative likelihood ratio is 0.15 (95% CI, 0.06 to 0.38).
Table 1. Operating Characteristics of the Clinical Prediction Rule for the Termination of Resuscitation in Out-of-Hospital Cardiac Arrests.
These likelihood ratios indicate only a mediocre diagnostic test if used to decide to transport a patient to the emergency department, suggesting that the rule is far from being useful for routine clinical application.
Dan Mayer, M.D.
Albany Medical College
Albany, NY 12208
mayerd@mail.amc.edu
To the Editor: Although the intended goal of Morrison et al. (preservation of limited resources) is laudable, they are addressing only a small part of the implied problem — that is, inappropriate use of emergency services. Generally, many more patients use emergency medical services (EMS) and emergency departments for illnesses that do not constitute an emergency (e.g., simple viral infections).1 The application of the TOR protocol would lead to a paradoxical EMS response: if you call EMS for a cardiac arrest, you may not be transported to the hospital, whereas if you call EMS for a common cold, you will be taken to the emergency department. This situation is likely to be unpopular with patients, physicians, and EMS workers alike. An alternative use of the TOR data may be for the emergency department staff to terminate resuscitation in the emergency department.
Siu Fai Li, M.D.
Jacobi Medical Center
Bronx, NY 10461
References
Patterson PD, Baxley EG, Probst JC. Medically unnecessary emergency medical services (EMS) transports among children ages 0 to 17 years. Matern Child Health J (in press).
To the Editor: Morrison et al. prospectively validated a prediction rule for the termination of futile efforts at resuscitation, citing several safety and cost advantages to society. One area in which society may suffer because of the cessation of cardiopulmonary resuscitation is in organ donation. After cardiac arrest, the patient may have progression to brain death as a consequence of anoxic encephalopathy or may become a suitable donor after cardiac death.
Recently, a group of researchers from Madrid demonstrated excellent outcomes for transplantations of 273 kidneys from donors who were dead on arrival at the emergency department.1 We reviewed the data from our organ procurement organization regarding patients who were resuscitated after cardiac arrest, but who then had progression to brain death or cardiac death. Between January 2001 and July 2006, 235 organs were transplanted from 81 donors who died after cardiac arrest and from 28 who died after primary respiratory arrest. The beneficiaries of these unsuccessful efforts included 65 liver and 154 kidney recipients.
Terminating efforts at resuscitation in the field would result in fewer donors, exacerbating an already critical shortage of organs.
Paul Morrissey, M.D.
Rhode Island Hospital
Providence, RI 02903
pmorrissey@lifespan.org
Kevin O'Connor, P.A., M.S.
Organ Transplantation Breakthrough Collaborative
Newton, MA 02158
Posy During, B.A.
New England Organ Bank
Newton, MA 02158
References
Sanchez-Fructuoso AI, Marques M, Prats D, et al. Victims of cardiac arrest occurring outside the hospital: a source of transplantable kidneys. Ann Intern Med 2006;145:157-164.
The authors reply: B?ttiger and colleagues highlight the importance of high-quality cardiopulmonary resuscitation in optimizing rates of return of spontaneous circulation and survival. Our termination-of-resuscitation rule would predict the transportation to the emergency department of all patients with a return of spontaneous circulation. The rule was not applied to patients for whom there was a response to advanced cardiac life support. We are not aware of any reports identifying a statistically significant superiority in survival outcomes for patients who receive advanced cardiac life support as compared with patients who receive basic life support resuscitation in out-of-hospital cardiac arrest.1
Hauswald asks the important question of when the risk (to quality of life) outweighs the benefit. The majority of research on cardiac arrest shows that survivors have good cerebral performance category1 and health utility index2 scores. We echo the call for more discriminating assessment of neurologic outcomes after resuscitation.
We agree with Ajani and Waksman's observation that our study is limited by a variable enrollment rate among sites. Two small sites had reduced enrollment rates. We are unsure why. The training and oversight by the site coordinator and medical director were similar to those at all other participating sites. The demographic characteristics of patients with cardiac arrest and the response intervals were similar among the sites, suggesting that the results can be generalized. Only arrests of presumed cardiac cause were included in the study.3 We also agree that the rule should be implemented initially with medical oversight.
The two-by-two table can be set up as Mayer suggests if the rule is designed to identify survivors. Our rule is designed to identify patients who will not survive and should not be transported to the emergency department.
Li considers it a paradox that transportation of patients with cardiac arrest to the emergency department might decrease with implementation of the TOR rule, whereas transportation of patients with less serious conditions would continue. However, paramedics routinely screen patients for transportation according to their standing orders. We agree with Li that physician and public acceptance of the TOR rule will be an important barrier to address before it can be implemented.
Morrissey et al. state that implementing our rule may reduce the number of organ procurements from donors who have had a cardiac arrest. This conclusion is based on the retrospective review by Sanchez-Fructuoso et al. and a review of their own institutional data. It is likely that in systems that use their specific strategy of organ donation our rule would reduce the number of potential donors.
Laurie J. Morrison, M.D.
University of Toronto
Toronto, ON M4N 3M5, Canada
Alex Kiss, Ph.D.
Institute for Clinical and Evaluative Sciences
Toronto, ON M4N 3M5, Canada
P. Richard Verbeek, M.D.
University of Toronto
Toronto, ON M4N 3M5, Canada
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.
Stiell I, Nichol G, Wells G, et al. Health-related quality of life is better for cardiac arrest survivors who received citizen cardiopulmonary resuscitation. Circulation 2003;108:1939-1944.
Jacobs I, Nadkarni V, Bahr J, et al. Cardiac arrest and cardiopulmonary resuscitation outcome reports: update and simplification of the Utstein templates for resuscitation registries: a statement for healthcare professionals from a task force of the International Liaison Committee on Resuscitation (American Heart Association, European Resuscitation Council, Australian Resuscitation Council, New Zealand Resuscitation Council, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Councils of Southern Africa). Circulation 2004;110:3385-3397.
Would anyone ask about survival after motor vehicle accidents involving patients without safety belts in their cars? Why not just use cars with safety belts, even if doing so is more expensive? Let's think differently and send the advanced cardiac life support know-how of the emergency department — that is, experienced physicians — to our patients undergoing out-of-hospital cardiac arrest. Education and organization, not termination, make the difference.2,3,4
Bernd W. B?ttiger, M.D.
Erik Popp, M.D.
Peter Teschendorf, M.D.
University of Heidelberg
D-69120 Heidelberg, Germany
bernd.boettiger@med.uni-heidelberg.de
References
Morrison LJ, Visentin LM, Kiss A, et al. Validation of a rule for termination of resuscitation in out-of-hospital cardiac arrest. N Engl J Med 2006;355:478-487.
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.
B?ttiger BW, Grabner C, Bauer H, et al. Long term outcome after out-of-hospital cardiac arrest with physician staffed emergency medical services: the Utstein style applied to a midsized urban/suburban area. Heart 1999;82:674-679.
Fischer M, Krep H, Wierich D, et al. Comparison of the emergency medical services systems of Birmingham and Bonn: process efficacy and cost effectiveness. Anasthesiol Intensivmed Notfallmed Schmerzther 2003;38:630-642.
To the Editor: The investigators in the TOR trial address one important aspect of cardiac resuscitation: When does survival become so unlikely that it does not merit further treatment? They do not directly address a more difficult question: When does the risk exceed the benefit? The primary risk of cardiac resuscitation is not death (which would occur without treatment) but rather survival with a disability that the patient would view as being worse than death. Even category I cerebral performance may not be normal, and many survivors have significant neurologic injury.
Several years ago, a colleague and I surveyed providers who performed cardiac resuscitation on a regular basis, and most of them wanted their own resuscitation to be stopped shortly after the first attempts at defibrillation.1 It is difficult to determine how long a cardiac resuscitation attempt should continue, but it is clear that the current practice of continuing until there is essentially no hope of survival poses difficult ethical questions.
Mark Hauswald, M.D.
University of New Mexico
Albuquerque, NM 87107
mhauswald@salud.unm.edu
References
Hauswald M, Tanberg D. Out-of-hospital resuscitation preferences of emergency health care workers. Am J Emerg Med 1993;11:221-224.
To the Editor: Morrison et al. attempted to validate a three-part clinical prediction rule for the termination of basic life support resuscitative efforts during out-of-hospital cardiac arrests. The study, however, has several limitations. First, although the data were analyzed prospectively, this was not a consecutive series of patients, since site-specific enrollment ranged from 21 to 100% of all eligible patients. Second, the reasons for variable site recruitment rates are not disclosed; a potential selection bias exists for patients at higher risk for death, which would favor the prediction rule. Finally, the authors should disclose the identified clinical variables (including the type of cardiac arrest) that were associated with survival until hospital discharge. Therefore, we suggest that these rules should be minimal requirements but that they should not override clinical judgment in determining when enough is enough.
Andrew E. Ajani, M.B., M.D.
Royal Melbourne Hospital
Melbourne 3050, Australia
Ron Waksman, M.D.
Washington Hospital Center
Washington, DC 20010
ron.waksman@medstar.net
To the Editor: The study conducted by Morrison et al. to validate a rule for terminating basic life support resuscitation in out-of-hospital cardiac arrest defined the test characteristics incorrectly. The definition of a positive "test" should be the decision to transport the patient to an emergency department (rather than the decision to terminate basic life support resuscitative efforts) and the "disease" should be survival (the preferred outcome for the patient, rather than death). With the use of this schema, the sensitivity of the transport decision with the rule is 90.2%, and the specificity is 64.4% — the reverse of the figures reported by Morrison and colleagues. With the use of their methods, the positive likelihood ratio (the sensitivity of the rule recommending the termination of basic life support resuscitative efforts, divided by 1 minus the specificity of the rule recommending termination) is 6.6 (95% confidence interval , 2.60 to 16.76), and the negative likelihood ratio (1 minus the sensitivity of the rule recommending transportation to an emergency department and continuation of basic life support resuscitative efforts, divided by the specificity of the rule recommending transportation) is 0.39 (95% CI, 0.35 to 0.45). With the use of the more intuitively correct numbers in Table 1, the positive likelihood ratio is 2.53 (95% CI, 2.23 to 2.87), and the negative likelihood ratio is 0.15 (95% CI, 0.06 to 0.38).
Table 1. Operating Characteristics of the Clinical Prediction Rule for the Termination of Resuscitation in Out-of-Hospital Cardiac Arrests.
These likelihood ratios indicate only a mediocre diagnostic test if used to decide to transport a patient to the emergency department, suggesting that the rule is far from being useful for routine clinical application.
Dan Mayer, M.D.
Albany Medical College
Albany, NY 12208
mayerd@mail.amc.edu
To the Editor: Although the intended goal of Morrison et al. (preservation of limited resources) is laudable, they are addressing only a small part of the implied problem — that is, inappropriate use of emergency services. Generally, many more patients use emergency medical services (EMS) and emergency departments for illnesses that do not constitute an emergency (e.g., simple viral infections).1 The application of the TOR protocol would lead to a paradoxical EMS response: if you call EMS for a cardiac arrest, you may not be transported to the hospital, whereas if you call EMS for a common cold, you will be taken to the emergency department. This situation is likely to be unpopular with patients, physicians, and EMS workers alike. An alternative use of the TOR data may be for the emergency department staff to terminate resuscitation in the emergency department.
Siu Fai Li, M.D.
Jacobi Medical Center
Bronx, NY 10461
References
Patterson PD, Baxley EG, Probst JC. Medically unnecessary emergency medical services (EMS) transports among children ages 0 to 17 years. Matern Child Health J (in press).
To the Editor: Morrison et al. prospectively validated a prediction rule for the termination of futile efforts at resuscitation, citing several safety and cost advantages to society. One area in which society may suffer because of the cessation of cardiopulmonary resuscitation is in organ donation. After cardiac arrest, the patient may have progression to brain death as a consequence of anoxic encephalopathy or may become a suitable donor after cardiac death.
Recently, a group of researchers from Madrid demonstrated excellent outcomes for transplantations of 273 kidneys from donors who were dead on arrival at the emergency department.1 We reviewed the data from our organ procurement organization regarding patients who were resuscitated after cardiac arrest, but who then had progression to brain death or cardiac death. Between January 2001 and July 2006, 235 organs were transplanted from 81 donors who died after cardiac arrest and from 28 who died after primary respiratory arrest. The beneficiaries of these unsuccessful efforts included 65 liver and 154 kidney recipients.
Terminating efforts at resuscitation in the field would result in fewer donors, exacerbating an already critical shortage of organs.
Paul Morrissey, M.D.
Rhode Island Hospital
Providence, RI 02903
pmorrissey@lifespan.org
Kevin O'Connor, P.A., M.S.
Organ Transplantation Breakthrough Collaborative
Newton, MA 02158
Posy During, B.A.
New England Organ Bank
Newton, MA 02158
References
Sanchez-Fructuoso AI, Marques M, Prats D, et al. Victims of cardiac arrest occurring outside the hospital: a source of transplantable kidneys. Ann Intern Med 2006;145:157-164.
The authors reply: B?ttiger and colleagues highlight the importance of high-quality cardiopulmonary resuscitation in optimizing rates of return of spontaneous circulation and survival. Our termination-of-resuscitation rule would predict the transportation to the emergency department of all patients with a return of spontaneous circulation. The rule was not applied to patients for whom there was a response to advanced cardiac life support. We are not aware of any reports identifying a statistically significant superiority in survival outcomes for patients who receive advanced cardiac life support as compared with patients who receive basic life support resuscitation in out-of-hospital cardiac arrest.1
Hauswald asks the important question of when the risk (to quality of life) outweighs the benefit. The majority of research on cardiac arrest shows that survivors have good cerebral performance category1 and health utility index2 scores. We echo the call for more discriminating assessment of neurologic outcomes after resuscitation.
We agree with Ajani and Waksman's observation that our study is limited by a variable enrollment rate among sites. Two small sites had reduced enrollment rates. We are unsure why. The training and oversight by the site coordinator and medical director were similar to those at all other participating sites. The demographic characteristics of patients with cardiac arrest and the response intervals were similar among the sites, suggesting that the results can be generalized. Only arrests of presumed cardiac cause were included in the study.3 We also agree that the rule should be implemented initially with medical oversight.
The two-by-two table can be set up as Mayer suggests if the rule is designed to identify survivors. Our rule is designed to identify patients who will not survive and should not be transported to the emergency department.
Li considers it a paradox that transportation of patients with cardiac arrest to the emergency department might decrease with implementation of the TOR rule, whereas transportation of patients with less serious conditions would continue. However, paramedics routinely screen patients for transportation according to their standing orders. We agree with Li that physician and public acceptance of the TOR rule will be an important barrier to address before it can be implemented.
Morrissey et al. state that implementing our rule may reduce the number of organ procurements from donors who have had a cardiac arrest. This conclusion is based on the retrospective review by Sanchez-Fructuoso et al. and a review of their own institutional data. It is likely that in systems that use their specific strategy of organ donation our rule would reduce the number of potential donors.
Laurie J. Morrison, M.D.
University of Toronto
Toronto, ON M4N 3M5, Canada
Alex Kiss, Ph.D.
Institute for Clinical and Evaluative Sciences
Toronto, ON M4N 3M5, Canada
P. Richard Verbeek, M.D.
University of Toronto
Toronto, ON M4N 3M5, Canada
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.
Stiell I, Nichol G, Wells G, et al. Health-related quality of life is better for cardiac arrest survivors who received citizen cardiopulmonary resuscitation. Circulation 2003;108:1939-1944.
Jacobs I, Nadkarni V, Bahr J, et al. Cardiac arrest and cardiopulmonary resuscitation outcome reports: update and simplification of the Utstein templates for resuscitation registries: a statement for healthcare professionals from a task force of the International Liaison Committee on Resuscitation (American Heart Association, European Resuscitation Council, Australian Resuscitation Council, New Zealand Resuscitation Council, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Councils of Southern Africa). Circulation 2004;110:3385-3397.