Bispectral Index as a Predictive Factor for Neurological Outcome in Post-Resuscitated Patients who Undergo Hypothermia

ABSTRACT

PURPOSE: Bispectral index (BIS) is a non-invasive parameter that expresses the level of consciousness using a numerical value that ranges from 0-100. It can be easily conducted at the patient bed-side throughout a day. We studied whether BIS could be used as a predictive factor for neurological outcome in patients who undergo hypothermia after cardiopulmonary resuscitation. METHODS: The prospective study enrolled patients who underwent induced hypothermia with post-resuscitated state after cardiac arrest and presented to Chonnam National University Hospital from June, 2010 to October, 2010. BIS monitoring was conducted from admission at the intensive care unit until normal temperature was attained after the induction of hypothermia. The patients were divided into two groups based on neurological outcome at discharge and the values obtained from BIS monitoring were compared. RESULTS: Fourteen patients were included in this study. The mortality rate was 28.6% and five patients were discharged with Glasgow Pittsburgh Cerebral Performance Categories 1 or 2. The value of BIS at the start of rewarming was significantly different between the two groups according to neurological outcome, while the value of BIS upon reaching normal temperature did not differ statistically. The significant difference between the two groups was observed in the value of BIS from 19 hours after starting hypothermia. CONCLUSION: BIS can be used to predict the neurological outcome of patients who undergo resuscitation after cardiac arrest.