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 fall neurologic recovery. The Glasgow Coma Scale has also been used for prognostication. By the third day after arrest, a Glasgow score < 6 is followed, at best, by a persistent vegetative state. Finally, more selective application of CPR is probably the best way to improve outcome. When patients suffer from end-stage disease, malignancy, acquired immunodeficiency syndrome, or other problems that are associated with poor response to CPR, they should be given the opportunity to determine their own code status. Where possible, it is the obligation of the physician to educate patients with regard to the reality of CPR-the process, and the aftermath including broken bones, tubes, neurologic damage and likelihood of death (or vegetative survival). This is particularly important for patients at high risk for poor outcome. CPR should be offered in situations in which it has potential benefit, like any other therapeutic modality. Initiation of futile or near-futile CPR because of family demands or because the physician has failed to address the issue with the patient and/or family prior to the event should occur less frequently. On the other hand, outcome is improved by early defibrillation. High-impulse CPR with interposed abdominal compression leads to higher myocardial and cerebral perfusion pressures, the implication being a higher likelihood of resuscitation. It has been shown that a coronary perfusion-pressure gradient greater than 15 mm Hg is likely to be associated with successful resuscitation. Other techniques including the active compression-decompression device and portable extracorporeal pump oxygenation have not been adequately studied to determine the exact effect on outcome. However, the former looks much more promising than the latter. Perhaps, as technology evolves, we will have modalities that can impact mortality from cardiac arrest in a meaningful way. Continuing improvement in prediction of outcome and assessment of benefits of new techniques will allow more informed choices by patients and caregivers in providing or not providing this costly therapy. Earlier prediction-during actual resuscitation-of ultimate futility is needed to help decide when enough is enough.
|Number of pages
|Published - Jan 1 1995
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine