The utility of bispectral index monitoring for sedated patients treated with low-dose remifentanil

The aim of the present study was to determine the effect of low-dose remifentanil on the monitoring quality of the Bispectral index for mechanically ventilated patients. Twelve patients who underwent elective surgery and required mechanical ventilation post-operatively were enrolled in this study with written informed consent. Eligible patients were divided into two groups. Patients in the remifentanil group received low-dose remifentanil (0.05–0.125 μg/kg/min) and propofol (1–3 mg/kg/h). Patients in the control group received propofol (1–3 mg/kg/h). Levels of sedation were evaluated by both the Richmond Agitation Sedation Scale (RASS) and BIS monitor (A2000-XP, version 4.0, Aspect Medical Systems, Newton, USA). Monitoring quality was assessed by a correlation between RASS and BIS values. These values were assessed by single regression analysis and a P value of <0.05 was considered significant. There was a significant correlation between RASS and BIS values (P = 3 × 10⁻¹², R ² = 0.67) in the remifentanil group, but not in the control group (P = 0.50, R ² = 0.057). The administration of low-dose remifentanil makes BIS a more precise tool for sedated patients under mechanical ventilation in the ICU.