Intraoperative Bispectral Index Monitoring and Time to Extubation after Cardiac Surgery: Secondary Analysis of a Randomized Control Trial

1 Background: Fast track recovery is a care process goal after cardiac surgery. Intraoperative anesthetic 2 depth may impact recovery, but the impact of brain monitoring on time to extubation and ICU length of 3 stay after cardiac surgery has not been extensively studied. Our goal was to determine if BIS-guided 4 anesthesia improves time to extubation compared to MAC-guided anesthesia in a cardiac surgery 5 population. 6 Methods: In this secondary outcome analysis of a randomized controlled study, we analyzed 294 7 patients undergoing elective coronary bypass grafting, valve replacements, and bypass plus valve 8 replacements at a single tertiary referral center between February 1, 2009 and April 30, 2010. Patients 9 were preoperatively randomized to BIS-guided anesthesia alerts (n=131) or MAC-guided anesthesia 10 alerts (n=163). The primary outcome measure was time to extubation in the BIS-guided and anesthetic 11 concentration-guided groups. Secondary outcomes were length of stay in the intensive care unit (ICU) 12 and total postoperative hospital length of stay. 13 Results: Valid extubation time data were available for 247 of 294 patients. The median [IQR] time to 14 extubation was 307 [215 to 771] minutes in the BIS group and 323 [196 to 730] minutes in the 15 anesthetic concentration group (p=0.61). The median [IQR] ICU length of stay was 54 [29 to 97] hours 16 versus 70 [44 to 99] hours (p=0.11). In terms of postoperative hospital length of stay, there was no 17 difference between the groups with median [IQR] times of 6 [5 to 8] days (p=0.69) in each group. 18 Conclusions: The use of intraoperative BIS monitoring during cardiac surgery did not change time to 19 extubation, ICU length of stay nor hospital length of stay. Data regarding BIS monitoring and recovery in 20 an exclusively cardiac surgery population are consistent with recent effectiveness studies in the general 21 surgical population. 22 Trial registration: ClinicalTrials.gov number NCT00689091 23