Prognostication after cardiac arrest and hypothermia: a prospective study.
OBJECTIVE
Current American Academy of Neurology (AAN) guidelines for outcome prediction in comatose survivors of cardiac arrest (CA) have been validated before the therapeutic hypothermia era (TH). We undertook this study to verify the prognostic value of clinical and electrophysiological variables in the TH setting.


METHODS
A total of 111 consecutive comatose survivors of CA treated with TH were prospectively studied over a 3-year period. Neurological examination, electroencephalography (EEG), and somatosensory evoked potentials (SSEP) were performed immediately after TH, at normothermia and off sedation. Neurological recovery was assessed at 3 to 6 months, using Cerebral Performance Categories (CPC).


RESULTS
Three clinical variables, assessed within 72 hours after CA, showed higher false-positive mortality predictions as compared with the AAN guidelines: incomplete brainstem reflexes recovery (4% vs 0%), myoclonus (7% vs 0%), and absent motor response to pain (24% vs 0%). Furthermore, unreactive EEG background was incompatible with good long-term neurological recovery (CPC 1-2) and strongly associated with in-hospital mortality (adjusted odds ratio for death, 15.4; 95% confidence interval, 3.3-71.9). The presence of at least 2 independent predictors out of 4 (incomplete brainstem reflexes, myoclonus, unreactive EEG, and absent cortical SSEP) accurately predicted poor long-term neurological recovery (positive predictive value = 1.00); EEG reactivity significantly improved the prognostication.


CONCLUSIONS
Our data show that TH may modify outcome prediction after CA, implying that some clinical features should be interpreted with more caution in this setting as compared with the AAN guidelines. EEG background reactivity is useful in determining the prognosis after CA treated with TH.
Rossetti
Andrea O
AO
Department of Neurology, University Hospital and Faculty of Biology and Medicine, Lausanne, Switzerland. andrea.rossetti@chuv.ch
Oddo
Mauro
M
Logroscino
Giancarlo
G
Kaplan
Peter W
PW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D016757:Death, Sudden, Cardiac; D003951:Diagnostic Errors / Q000517:prevention & control; D004569:Electroencephalography / Q000379:methods; D005073:Evoked Potentials, Somatosensory; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007036:Hypothermia, Induced / Q000706:statistics & numerical data*; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D009460:Neurologic Examination; D018458:Persistent Vegetative State / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D055815:Young Adult