Comparison of Quantium Consciousness Index and Richmond Agitation Sedation Scale in Mechanically Ventilated Critically Ill Patients: An Observational Study

Abstract

Background: The quantium consciousness index (qCON), an electroencephalography (EEG)-based modality, has no studies regarding intensive care unit (ICU) sedation, though very few studies describe its use for assessing depth of anesthesia in the operation theater. In this study, we evaluated qCON for assessing sedation compared with Richmond Agitation Sedation Scale (RASS) in patients on a mechanical ventilator in the ICU. Methods: Eighty-seven mechanically ventilated patients aged between 18 and 60 years were investigated over a 12-hour period. They were given a standardized dosage of sedation comprised of a bolus dose of propofol 0.5 mg/kg and fentanyl 1 µg/kg, and then infusions of propofol 2–5 mg/kg/hour and fentanyl 0.5–2 µg/kg/hour. These drug infusions were adjusted to achieve a RASS score between 0 and-3. Using the qCON monitor, the investigator recorded the qCON values and then assessed the RASS score. Results: A total of 1,218 readings were obtained. After contrasting each qCON value correspondingly with time to each RASS value, we found their correlation to be statistically significant (ρ = 0.288, p <0.0001). With the help of receiver operating characteristic (ROC) curves, we were able to differentiate appropriate from inappropriate levels of sedation. A qCON value of 80 had a sensitivity of 72.67% and a specificity of 67.42% (AUC 0.738 with SE 0.021). Conclusion: qCON can be used for assessing sedation levels in mechanically ventilated critically ill patients.