Bispectral index (BIS) and suppression ratio (SR) as an early predictor of unfavourable neurological outcome after cardiac arrest.

INTRODUCTION: Predicting the neurological outcome after cardiopulmonary resuscitation (CPR) is extremely difficult. We tested the hypothesis whether monitoring of bispectral index (BIS) and suppression ratio (SR) could serve as an early prognostic indicator of neurological outcomes after CPR. METHODS: Cerebral monitoring (BIS, SR) was started as soon as possible after initiation of CPR and was continued for up to 72h. The functional neurological outcome was measured on day 3, day 7 and again one month after CPR via a clinical examination and assessment according to the cerebral performance category score (CPC). RESULTS: In total 79 patients were included. Of these, 26 patients (32.9%) survived the observation period of one month; 7 of them (8.9%) showed an unfavourable neurological outcome. These 7 patients had significantly lower median BIS values (25 [21;37] vs. 61 [51;70]) and higher SR (56 [44;64] vs. 7 [1;22]) during the first 4h after the initiation of CPR. Using BIS<40 as threshold criteria, unfavourable neurological outcome was predicted with a specificity of 89.5% and a sensitivity of 85.7%. The odds ratio for predicting an unfavourable neurological outcome was 0.921 (95% CI 0.853-0.985). The likelihood to remain in a poor neurological condition decreased by 7.9% for each additional point of BIS, on average. CONCLUSION: Our results suggest that BIS and SR are helpful tools in the evaluation of the neurological outcomes of resuscitated patients. Nevertheless, therapeutic decisions have to be confirmed through further examinations due to the far-ranging consequences of false positive results.

Bispectral index monitoring during cardiopulmonary resuscitation repeated twice within 8 days in the same patient: a case report.

Research on cardiac resuscitation has led to various changes in the techniques and drug administration involved in modern advanced life support. Besides improving primary cardiac survival, interest is increasingly focused on a favourable neurological outcome. However, until now there has been no on-site equipment to support the clinical observations of the cardiopulmonary resuscitation (CPR) team. Bispectral index (BIS) monitoring has been used for avoiding awareness during anaesthesia for many years. We report a case of a 68-year-old patient suffering twice from cardiac arrest due to thromboembolism within a few days. While the first cardiac resuscitation was survived without neurological consequences, the patient died after the second event. Both resuscitation events were monitored using the BIS. We discuss the course of BIS values and their possible contribution to the prediction of outcome.