Resuscitation: when is enough, enough?

Almost half of patients respond acutely to resuscitation but most die within the first several days after arrest. The incidence of survival to discharge from the hospital after cardiopulmonary arrest is about 15%; one third of those surviving have evidence of neurologic deficits. Although some prognostic variables are useful in determining which patients are most likely to die prior to discharge from the hospital, each patient needs to be evaluated on an individual basis and the various risk factors weighed carefully. As additional data accumulate, we may well be more effective at deciding which patients are more likely to benefit from CPR so that we can more judiciously apply this therapeutic modality. A number of studies have identified factors that contribute to poor outcome. Patients over 70 years of age usually fare poorly after CPR, but this is more a reflection of the number of coexisting diagnoses rather than years. Although initial survival may not be different from younger patients, fewer elderly patients live to discharge and more are likely to have neurologic sequelae. Concurrent diagnoses such as sepsis, AIDS, gastrointestinal bleeding, renal failure, cancer, and central nervous system disease have a universally poor response to CPR. If defibrillation occurs more than 6 minutes after arrest or on the general ward or if the resuscitative attempt lasts longer than 15 minutes, mortality is greater than 95%. If CPR continues for more than 30 minutes, there are no survivors. A low exhaled CO2 concentration (< 2%) during cardiac massage, asystole or EMD as the first identified rhythm, and recurrent arrest also carry a poor prognosis. On the other hand, at the time of arrest or during the immediate postarrest period, poor neurologic status is a less helpful predictor. The absence of spontaneous respiration is the only variable at the time of admission after out-of-hospital arrest that is particularly ominous. There is no evidence to suggest that the absence of spontaneous respiration implies any better prognosis for patients arresting in the hospital. Coma, hypoxic myoclonus, and absent reflexes, while not useful immediately following arrest, are of greater prognostic significance 48 hours later. Only 5% of patients who are unconscious 48 hours after arrest will have a full neurologic recovery. The Glasgow Coma Scale has also been used for prognostication.(ABSTRACT TRUNCATED AT 400 WORDS)