The natural course of neurological recovery following cardiopulmonary resuscitation
Introduction
Every day, thousands of people all over the world are resuscitated from circulatory arrest. Most are left with neurological deficits. Various means have been recommended to improve the course of brain recovery after resuscitation 1, 2. However, any such recommendation requires a fair knowledge of the natural history of global brain ischaemia. Without such knowledge it is difficult to detect possible ischaemic damage to the brain and to assess whether interventions influence neurological recovery favourably.
Many studies have sought predictive variables in victims of circulatory arrest 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19. But none of these studies described the hour by hour course of post-ischaemic brain recovery.
We have previously described neurological recovery following circulatory arrest in patients who had no cortical activity in their immediate post-resuscitation EEG 20, 21, 22. The sequential features of recovery with time in such a highly selected population of patients need not be applicable to victims of circulatory arrest in general. We therefore compared previous experiences with the findings in a group with circulatory arrest who retained some cortical activity reflected by the initial EEG recording for the purpose of defining common features of post-ischaemic brain recovery.
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Study population
The study was conducted in the coronary and intensive care units of two university hospitals (Glostrup County Hospital and Rigshospitalet) in the Copenhagen area during a period of 8 years. One of us (EOJ) had witnessed the efforts at resuscitation in 613 victims of circulatory arrest but had no influence on treatment decisions. As a principle, all patients received maximal life-sustaining treatment which also included the use of mechanical ventilation.
Circulation was restored in 329 patients.
Overall course of neurological recovery
Fig. 1 shows that patients in Group I remained unconscious and suffered brain death less often than those in Group II (P<0.001 and 0.01, respectively, Fisher). Persistent deficits after awakening were, however, equally often encountered.
Findings in patients remaining unconscious
Twenty-eight patients in Group I and 88 in Group II remained unconscious. The time course of neurological recovery and deterioration and the rates of final asystole were similar in the two population subsets (Fig. 2). The proportion of patients (P) present
Discussion
The present report establishes that orderly brain recovery can be identified during the period of unconsciousness by a fixed-order return of interrelated neurological signs and EEG configurations; and, after awakening by a fixed-order return of motor, sensory and mental faculties. A similar systematic description of the natural history of global brain ischaemia is not available in the literature. However, Bokonjic [25], who studied 27 patients retrospectively following circulatory arrest or
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