The bispectral index and suppression ratio are very early predictors of neurological outcome during therapeutic hypothermia after cardiac arrest.
OBJECTIVE
To evaluate the bispectral index (BIS) and suppression ratio (SR) as very early predictors of neurological outcome during therapeutic hypothermia after cardiac arrest.


METHODS
Demographic data, BIS1, and SR1 were recorded from 97 patients after the first dose of neuromuscular blockade, with outcomes blinded, and compared to the discharge Cerebral Performance Category (CPC). Receiver-operator characteristic curves and a multiple logistic regression model were constructed to predict good (CPC 1-2, GO) and poor (CPC 3-5, PO) neurological outcomes.


RESULTS
Fourteen patients were excluded from the final analysis; 33 of the remaining 83 patients (40%) were classified as GO. The BIS1 was higher in patients with GO (37 [28-40] vs. 7 [3-15], p < 0.001). BIS1 < 22 predicted PO with a likelihood ratio (LR) of 14.2 and an area under the curve (AUC) of 0.91 (95% CI 0.85-0.98, p < 0.001). SR1 > or =48 predicted PO with a LR of 12.7 and an AUC of 0.90 (95% CI 0.83-0.98, p < 0.001). Both BIS1 (DeltaAUC 0.16, p = 0.006) and SR1 (DeltaAUC 0.16, p = 0.005) predicted outcomes better than the time to return of spontaneous circulation.


CONCLUSIONS
In our single-center cohort utilizing moderate sedation, the bispectral index and suppression ratio recorded after the first dose of intermittent neuromuscular blockade were accurate and very early predictors of neurological outcome during therapeutic hypothermia after cardiac arrest.
Seder
David B
DB
Neuroscience Institute, Maine Medical Center, 22 Bramhall St, Portland, ME 04102, USA. sederd@mmc.org
Fraser
Gilles L
GL
Robbins
Tracy
T
Libby
Laurel
L
Riker
Richard R
RR
D000368:Aged; D003128:Coma / Q000175:diagnosis* / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D006323:Heart Arrest / Q000453:epidemiology* / Q000517:prevention & control*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012121:Respiration, Artificial; D013997:Time Factors