Assessing Prognosis Following Cardiopulmonary Resuscitation and Therapeutic Hypothermia-a Critical Discussion of Recent Studies

Background: The prognosis of patients who are comatose after cardiopulmonary resuscitation (CPR) is poor but can be improved by mild therapeutic hypothermia. We studied the question whether the known, reliable indicators of a poor prognosis after CPR are also valid for patients treated with CPR and hypothermia. Methods: This review is based on a selective search of the PubMed database for recent articles on the assessment of prognosis in persons who are comatose after CPR and therapeutic hypothermia. Results: On the basis of 21 clinical trials, 4 of which yielded level I evidence, 9 level II evidence, and 8 level III evidence, the following were identified as reliable indicators of a poor prognosis: generalized myoclonus, bilateral absence of the pupillary light response or of the corneal reflex, bilateral absence of the cortical components of median nerve somatosensory evoked potentials, a burst-suppression or isoelectric EEG, continuous generalized epileptiform discharges, and an elevated serum concentration of neuron-specific enolase (with a higher cutoff value than for normothermic patients). Conclusion: If the prognosis is poor, this should be thoroughly discussed with the patient's family, and the nature and extent of further intensive treatment should be reconsidered. The patient's wishes, if known, are paramount. Any decision to withhold care should be taken only if there are multiple concurrent indicators of a poor prognosis. If only one such indicator is present, or if the findings are inconsistent, such decisions should be postponed.