OBJECTIVE: To compare the value of bispectral index (BIS) monitoring and sedation agitation scale (SAS) in guiding intensive care unit (ICU) sedation therapy for the patients undergoing short term mechanical ventilation.
METHODS: One hundred and five patients aged 18-60 years after operation receiving mechanical ventilation for longer than 12 hours in ICU were enrolled in this study. The patients were randomly divided into two groups: BIS guided group (n=42) and SAS guided group (n=63). All of them received protocolized continuous sedation and analgesia by using fentanyl for analgesia and propofol plus midazolam to sedate intravenously. The effect of sedation was assessed every hour till BIS reaching 50-70 or SAS reaching grade 3-4. Sedatives and analgesics were suspended at 6:00 am on next day after ICU admission , and BIS and the SAS were recorded every hour, sedation time, time to wake up, duration of mechanical ventilation, daily dosage of midazolam and propofol, and the incidence of adverse events including restlessness after suction, endotracheal tube resistance, pain tolerance during sedation, and delirium after extubation were all recorded accordingly.
RESULTS: Dosages of midazolam and propofol were found higher in BIS guided group than the SAS guided group [midazolam (mg×kg(-1) ×h(-1) ): 0.10±0.02 vs. 0.09±0.02, propofol (mg×kg(-1) ×h(-1) ): 0.95±0.23 vs. 0.86±0.20, both P<0.05]. The total time (D t) of patients under sedative control was significantly longer in BIS guided group compared with SAS guided group, and also in first three hours [D 1, D 2, D 3, D t: 75.2% (507) vs. 52.8% (421), D 1: 78.6% (33) vs. 22.2% (14), D 2: 88.1% (37) vs. 20.6% (13), D 3: 81.0% (34) vs. 31.7% (20), all P<0.01]. The time to wake up (minutes) was significantly shorter in BIS guided group compared with SAS guided group [0 (0, 20) vs. 15 (0, 47), P<0.05]. No significant difference in acute physiology and chronic health evaluation II (APACHE II) score (3.57±2.60 vs. 4.19±2.30), duration of mechanical ventilation [hours: 16.5 (14.5, 19.0) vs. 17.0 (15.0, 19.0)], sedation time [hours: 14.0 (12.9, 17.1) vs. 16.0 (13.0, 18.0)] and incidence of adverse events including restlessness after suction (81.0% vs. 79.4%), endotracheal tube resistance (71.4% vs. 74.6%), pain tolerance during sedation (92.8% vs. 93.6%) and delirium after extubation (4.8% vs. 1.6%) was found between BIS guided group and SAS guided group (all P>0.05).
CONCLUSION: BIS monitoring is better in sedative control than SAS assessment for ICU patients undergoing short term mechanical ventilation.
