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The inability of physicians to predict the outcome of in-hospital resuscitation
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Literature of resuscitation
RwtmdtaUve hy~u&n& Marion DW, Leonov Y, Ginsberg M, Katz LM, Kochanek PM, Lechleuthner A, Nemoto EM, Obrist W, Safar P, Stem F, Tisherman SA, White RJ, Xiao F, Zar H Department of Neurological Surgery, Presbyterian University Hospital, Univ. of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA Crit Care Med 19%; 24l2 (Suppl.): S81-S89 Resuscitative (postinsult) hypothermia is less well studied than protective-preservative (pm- and i&a-arrest) hypothermia. The latter is in wide clinical use, particularly for protecting the brain during cardiac surgery. Resuscitative hypothermia was explored in the 1950s and then lay dormant until the 1980s when it was revived. This change occurred through the discoveries of brain damage mitigating effects after cardiac arrest in dogs, and after forebrain ischemia in rats, of mild (34OC) hypothermia (which is safe), and of benefits derived from moderate hypothermia (3oOC) after traumatic brain injury or focal brain ischemia in various species. The idea that protection-preservation or resuscitation by hypothermia is mainly explained by its ability to reduce cerebral oxygen demand has been replaced by an increasingly documented synergism of many beneficial mechanisms. Deleterious chemical cascades during and after these insults are suppressed even by mild hypothermia. Prolonged moderate hypothermia carries some risks, e.g., arrhythmias, infection and coagulopathies. These side effectsneed further study. In global brain ischemia, protective-preservative mild hypothermia provides lasting mitigation of brain damage. Resuscitative mild hypothermia, however, may be beneficial in terms of long-term outcome or may merely delay the inevitable loss of selectively vulnerable neurons. Even if the latter is true, mild hypothermia may extend the therapeutic window for other interventions. This extension of the therapeutic window requires further documentation. After normothermic cardiac arrest of 11 min in dogs, mild resuscitative hypothermia from I5 min to 12 h after reperfusion plus cerebral blood flow promotion normalized functional recovery with the least histologic damage seen thus far. Optimal duration of, and rewarming methods from, resuscitative hypothermia need clarification. The earliest possible induction of mild hypothermia after cardiac arrest seems desirable. Head- neck surface cooling alone is too slow. Among many clinically feasible rapid cooling methods, carotid cold flush and peritoneal cooling look promising. After traumatic brain injury or focal brain ischemia, which Seem to still benefit from even later cooling, surface cooling methods may be adequate. Resuscitative hypothermia after cardiac arrest, traumatic brain injury, or focal brain ischemia should be considered for clinical trials. Tlte&abilityof+yskbmstoPredktthewteomeof~itaJ
mmeitatinn EbeJl MH, Bergus GR, Warbasse L, Bloomer R Department of Family Medicine, Wayne State University, 4201 St. Antoine UCH-QJ, Detriot. MI 48H)l, USA J Gen Intern Med 1996; 11/l: 16-22 Objective: To measure the accuracy, reliability, and discrimination of physicians’ predictions of the outcome of in-
hospital cardiopulmonary resuscitation (CPR), using a large series of detailed clinical vignettes of patients with known outcomes, Design: Faculty and resident physicians at three university-affiliated generalist training programs were given one-page summaries of admission data for patients who later underwent in-hospital CPR. These summaries included all prearrest variables known to be related to the outcome of CPR. Physicians were asked to estimate the probability that patients would survive the resuscitation long enough to be stabilixed, and the probability of survival to discharge. Setting: Patient cases were derived from a consecutive series of patients undergoing CPR at two urban teaching hospitals in Detroit, Michigan, Participants: Faculty members and residents at a university-based department of internal medicine and two university- based departments of family medicine were surveyed. Interventions: Accuracy of the physician predictions was assessedby comparing the mean predicted probability of survival with the percentage of patients who actually survived. The reliability of probability estimates of survival was evaluated by assessingthe numerical proximity of the estimates to the actual outcome of the resuscitative effort. The ability to discriminate between survivors and nonsurvivors was measured by comparing the mean predicted probability of survival for those patients who survived CPR with that for those who did not, and by stratifying physician predictions and measuring the area under a receiver operating characteristic (RGC) curve. Measurements and main results: Physicians (n = 51) made a total of 713 estimates, and showed poor accuracy, reliability, and discrimination in predicting the outcome of inhospital CPR. The mean predicted probability of survival to discharge did not differ between patients who actually survived to discharge and those who did not (29.5% vs 26.4%, z = 0.35, p = 0.73). Similarly, the mean predicted probabilities of surviving resuscitation were the same for patients who actually survived long enough to be stabilized and those who did not (37.8% vs 39.9%, z = 0.55, p = 0.58). Accounting for type of physician and institution by analysis of variance did not change this finding. The area under the RGC curve for the prediction of arrest survival was 0.476, which is not significantly different from 0.5, and is consistent with an ability to discriminate between survivors and nonsurvivors that is no better than random choice. Conclusions: Physicians were no better at identifying patients who would survive resuscitation than would be expected by chance alone. Further work is needed to establish which variables are used by physicians in the decision-making process, and to design educational interventions that will make physicians more accurate prognosticators.
Literature of resuscitation
RwtmdtaUve hy~u&n& Marion DW, Leonov Y, Ginsberg M, Katz LM, Kochanek PM, Lechleuthner A, Nemoto EM, Obrist W, Safar P, Stem F, Tisherman SA, White RJ, Xiao F, Zar H Department of Neurological Surgery, Presbyterian University Hospital, Univ. of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA Crit Care Med 19%; 24l2 (Suppl.): S81-S89 Resuscitative (postinsult) hypothermia is less well studied than protective-preservative (pm- and i&a-arrest) hypothermia. The latter is in wide clinical use, particularly for protecting the brain during cardiac surgery. Resuscitative hypothermia was explored in the 1950s and then lay dormant until the 1980s when it was revived. This change occurred through the discoveries of brain damage mitigating effects after cardiac arrest in dogs, and after forebrain ischemia in rats, of mild (34OC) hypothermia (which is safe), and of benefits derived from moderate hypothermia (3oOC) after traumatic brain injury or focal brain ischemia in various species. The idea that protection-preservation or resuscitation by hypothermia is mainly explained by its ability to reduce cerebral oxygen demand has been replaced by an increasingly documented synergism of many beneficial mechanisms. Deleterious chemical cascades during and after these insults are suppressed even by mild hypothermia. Prolonged moderate hypothermia carries some risks, e.g., arrhythmias, infection and coagulopathies. These side effectsneed further study. In global brain ischemia, protective-preservative mild hypothermia provides lasting mitigation of brain damage. Resuscitative mild hypothermia, however, may be beneficial in terms of long-term outcome or may merely delay the inevitable loss of selectively vulnerable neurons. Even if the latter is true, mild hypothermia may extend the therapeutic window for other interventions. This extension of the therapeutic window requires further documentation. After normothermic cardiac arrest of 11 min in dogs, mild resuscitative hypothermia from I5 min to 12 h after reperfusion plus cerebral blood flow promotion normalized functional recovery with the least histologic damage seen thus far. Optimal duration of, and rewarming methods from, resuscitative hypothermia need clarification. The earliest possible induction of mild hypothermia after cardiac arrest seems desirable. Head- neck surface cooling alone is too slow. Among many clinically feasible rapid cooling methods, carotid cold flush and peritoneal cooling look promising. After traumatic brain injury or focal brain ischemia, which Seem to still benefit from even later cooling, surface cooling methods may be adequate. Resuscitative hypothermia after cardiac arrest, traumatic brain injury, or focal brain ischemia should be considered for clinical trials. Tlte&abilityof+yskbmstoPredktthewteomeof~itaJ
mmeitatinn EbeJl MH, Bergus GR, Warbasse L, Bloomer R Department of Family Medicine, Wayne State University, 4201 St. Antoine UCH-QJ, Detriot. MI 48H)l, USA J Gen Intern Med 1996; 11/l: 16-22 Objective: To measure the accuracy, reliability, and discrimination of physicians’ predictions of the outcome of in-
hospital cardiopulmonary resuscitation (CPR), using a large series of detailed clinical vignettes of patients with known outcomes, Design: Faculty and resident physicians at three university-affiliated generalist training programs were given one-page summaries of admission data for patients who later underwent in-hospital CPR. These summaries included all prearrest variables known to be related to the outcome of CPR. Physicians were asked to estimate the probability that patients would survive the resuscitation long enough to be stabilixed, and the probability of survival to discharge. Setting: Patient cases were derived from a consecutive series of patients undergoing CPR at two urban teaching hospitals in Detroit, Michigan, Participants: Faculty members and residents at a university-based department of internal medicine and two university- based departments of family medicine were surveyed. Interventions: Accuracy of the physician predictions was assessedby comparing the mean predicted probability of survival with the percentage of patients who actually survived. The reliability of probability estimates of survival was evaluated by assessingthe numerical proximity of the estimates to the actual outcome of the resuscitative effort. The ability to discriminate between survivors and nonsurvivors was measured by comparing the mean predicted probability of survival for those patients who survived CPR with that for those who did not, and by stratifying physician predictions and measuring the area under a receiver operating characteristic (RGC) curve. Measurements and main results: Physicians (n = 51) made a total of 713 estimates, and showed poor accuracy, reliability, and discrimination in predicting the outcome of inhospital CPR. The mean predicted probability of survival to discharge did not differ between patients who actually survived to discharge and those who did not (29.5% vs 26.4%, z = 0.35, p = 0.73). Similarly, the mean predicted probabilities of surviving resuscitation were the same for patients who actually survived long enough to be stabilized and those who did not (37.8% vs 39.9%, z = 0.55, p = 0.58). Accounting for type of physician and institution by analysis of variance did not change this finding. The area under the RGC curve for the prediction of arrest survival was 0.476, which is not significantly different from 0.5, and is consistent with an ability to discriminate between survivors and nonsurvivors that is no better than random choice. Conclusions: Physicians were no better at identifying patients who would survive resuscitation than would be expected by chance alone. Further work is needed to establish which variables are used by physicians in the decision-making process, and to design educational interventions that will make physicians more accurate prognosticators.