Amplitude-integrated EEG (aEEG) predicts outcome after cardiac arrest and induced hypothermia
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To evaluate the use of continuous amplitude-integrated EEG (aEEG) as a prognostic tool for survival and neurological outcome in cardiac arrest patients treated with hypothermia.
Prospective, observational study.
Multidisciplinary intensive care unit in a university hospital.
Comatose survivors of cardiac arrest were treated with induced hypothermia for 24 h. An aEEG recording was initiated upon arrival at the ICU and continued until the patient regained consciousness or, if the patient remained in coma, no longer than 120 h. The aEEG recording was not available to the ICU physician, and the aEEG tracings were interpreted by a neurophysiologist with no knowledge of the patient's clinical status. Only clinically visible seizures were treated.
Measurements and results
Thirty-four consecutive hypothermia-treated cardiac arrest survivors were included. At normothermia (mean 37 h after cardiac arrest), the aEEG pattern was discriminative for outcome. All 20 patients with a continuous aEEG at this time regained consciousness, whereas 14 patients with pathological aEEG patterns (flat, suppression-burst or status epilepticus) did not regain consciousness and died in hospital. Patients were evaluated neurologically upon discharge from the ICU and after 6 months, using the Cerebral Performance Category (CPC) scale. Eighteen patients were alive with a good cerebral outcome (CPC 1--2) at 6-month follow-up.
A continuous aEEG pattern at the time of normothermia was discriminative for regaining consciousness. aEEG is an easily applied method in the ICU setting.
KeywordsCardiac arrest Coma Hypothermia aEEG Outcome
This study was supported by the Swedish Research Council, grant No. 84 (Ingmar Rosén). We would like to thank Bodil Persson, EEG technician, for excellent technical support. The assistance of Gisela Railo, occupational therapist, Dr Tobias Cronberg and Dr Håkan Widner at the Department of Neurology, Lund University Hospital is gratefully acknowledged.
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