The Natural History of Recovery Following Sudden Cardiac Arrest and Internal Cardioverter-Defibrillator Implantation


Prog Cardiovasc Nurs. 2001;16(4) 

In This Article

Neurologic Impairments Following SCA and ICD Implantation

Fewer than 60% of persons in whom cardiopulmonary resuscitation (CPR) is attempted following SCA will survive hospital admission, with 2%-44% reaching hospital discharge.[35] One of the primary factors limiting full recovery after successful CPR is the brain's ability to tolerate the insult of global ischemia that occurs at the time of resuscitation. A wide range of neurologic sequelae, ranging from mild impairments to brain death, have been reported in resuscitated victims of SCA.[27,37] Full neurologic recovery in SCA survivors is in the range of 12%-70%, depending on the methods used to measure neurocognitive functioning.[38,39,40] Although there is a relatively high probability that SCA survivors will incur some neurologic impairment, particularly early in recovery, neither neurologic examination nor neuropsychological testing is routinely completed at the time of hospital discharge. Mild to moderate cognitive impairments may therefore be unrecognized, minimized, denied, or misdiagnosed until work- or family-related problems develop.[18] Impairment in neurologic functioning has been linked to changes in work status and social relationships; greater psychological distress, including depression; and impaired family functioning.[22]

A number of clinical variables have been associated with neurologic outcomes following resuscitation, including time to postarrest awakening, the number of minutes until bystander CPR is initiated, time from collapse to first defibrillatory shock, time from collapse to the return of normal sinus rhythm, and time to receipt of advanced life support.[35,45] The American Heart Association's joint task force on uniform reporting for out-of-hospital cardiac arrest has identified the period of unconsciousness after resuscitation as a simple and reliable approach for determining postarrest cerebral outcomes.[45] Data from Project Restart in King County, Washington,[3] found that time to initiation of CPR (<4 min) and response times of medical personnel were significantly associated with postresuscitation survival. If definitive care (e.g., defibrillation, medications) was received within 8 minutes after collapse, 33% of patients lived to hospital admission, and 37% of these were discharged from the hospital. Other authors have reported that patients who are arousable 12-72 hours after resuscitation usually do well neurologically.[36,41] In an evaluation of 117 survivors of out-of-hospital cardiac arrest who were resuscitated and followed for 3.5 years, Earnest et al.[38] found that those who were awake on hospital admission and who survived medical complications had a 90% probability of good long-term neurologic function.

Transient cognitive changes may also occur due to other factors after SCA. These mental status changes may be due to depression,[18] antiarrhythmic drugs with central nervous system side effects, or hypoxia caused by low cardiac output states.[42] Sauve et al.[22] found that 40% of long-term survivors (21 months) report mildly to moderately severe changes in both memory and concentration, even though individuals with known neurologic deficits had been excluded from her study. Similar findings in memory impairment, concentration, attention, and construction ability have been reported in a 1-year follow-up study of SCA survivors,[10] with peak difficulty at hospital discharge. Neurologic deficits have been shown to include forgetfulness, changes in learning ability, and reductions in attention to environmental stimuli, comprehension, and problem-solving ability. Cognitive deficits have been associated with increased irritability and social isolation, subtle behavioral changes, and impatience. Roine et al.[43] concluded that about one half of survivors of out-of-hospital cardiac arrest will have persistent and permanent neurologic deficits (primarily memory loss) at 1 year.


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