Can Bispectral Index Monitoring (EEG) be an Early Predictor of Respiratory Depression under Deep Sedation during Endoscopic Retrograde Cholangiopancreatography?

OBJECTIVES: The more often the endoscopy sedation is performed, the more the risk of adverse events, and therefore, advanced monitoring becomes more and more essential in endoscopy units. The present study aims to evaluate whether the Bispectral Index (BIS) monitoring is an early predictor of respiratory depression and to determine the compliance between commonly used clinical sedation score. METHODS: This study was approved by the ethics committee. The sample consisted of 60 patients aged 18 to 50 years with an American Society of Anesthesiologists (ASA) physical status of I scheduled for endoscopic retrograde cholangiopancreatography (ERCP). All patients received propofol mediated sedation. Ramsay sedation score (RSS) was used as a clinical sedation score to assess the depth of sedation. Participants were attached to a BIS monitor. Perioperative hemodynamics, BIS values, the mean dose of propofol, procedure duration, apnea, frequency of oxygen desaturation and airway-related interventions, as well as demographic parameters, were recorded. BIS scores were blinded to RSS data. RESULTS: The study sample consisted of 60 patients (36 females) aged 18 to 50 years (mean: 36.10±8.02). The mean procedure time and the dose of propofol were 32.70±1.79 min and 287.17±59.66 mg, respectively. The cut-off values for respiratory depression were as follows. At the 15th min of measurement, the BIS score of 60 had 96.2% sensitivity and 42.9% specificity. At the 20th min of measurement, the BIS score of 59.50 had 98.2% sensitivity and 100.0% specificity. At the 25th min of measurement, the BIS score of 59.00 had 98.3% sensitivity and 50.0% specificity. Regression analysis showed that the mean BIS score (p=0.000, 95%CI-0.110-0.043) increased by 0.076 with a unit increase in the RSS. CONCLUSION: BIS was highly correlated with RSS, and therefore, can be used to avoid respiratory depression during sedation.