Cognitive and neurophysiological outcome of cardiac arrest survivors treated with therapeutic hypothermia.
OBJECTIVE
Cognitive deficits are common in survivors of cardiac arrest (CA). The aim of this study was to examine the effect of therapeutic hypothermia after CA on cognitive functioning and neurophysiological outcome.


METHODS
A cohort of 70 consecutive adult patients resuscitated from out-of-hospital ventricular fibrillation CA were randomly assigned to therapeutic hypothermia of 33 degrees C for 24 hours accomplished by external cooling or normothermia. Neuropsychological examination was performed to 45 of the 47 conscious survivors of CA (27 in hypothermia and 18 in normothermia group) 3 months after the incident. Quantitative electroencephalography (Q-EEG) and auditory P300 event-related potentials were studied on 42 patients at the same time point.


RESULTS
There were no differences between the 2 treatment groups in demographic variables, depression, or delays related to the resuscitation. No differences were found in any of the cognitive functions between the 2 groups. 67% of patients in hypothermia and 44% patients in normothermia group were cognitively intact or had only very mild impairment. Severe cognitive deficits were found in 15% and 28% of patients, respectively. All Q-EEG parameters were better in the hypothermia-treated group, but the differences did not reach statistical significance. The amplitude of P300 potential was significantly higher in hypothermia-treated group.


CONCLUSIONS
The use of therapeutic hypothermia was not associated with cognitive decline or neurophysiological deficits after out-of-hospital CA.
Tiainen
Marjaana
M
Department of Neurology, Meilahti Hospital, Haartmaninkatu 4, Finland. marjaana.tiainen@hus.fi
Poutiainen
Erja
E
Kovala
Tero
T
Takkunen
Olli
O
Häppölä
Olli
O
Roine
Risto O
RO
D000368:Aged; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control / Q000628:therapy; D015331:Cohort Studies; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006323:Heart Arrest / Q000150:complications*; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods; D002534:Hypoxia, Brain / Q000209:etiology / Q000517:prevention & control* / Q000628:therapy*; D020925:Hypoxia-Ischemia, Brain / Q000209:etiology / Q000517:prevention & control* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D016896:Treatment Outcome