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October 13, 2018
10/13/2018 1:15:00 PM - 10/13/2018 2:45:00 PM
Room North, Room 21
Combined Intraoperative Anesthesia and Analgesia Monitoring Impact on Safety and Recovery: Interim Analysis
Etienne Renaud-Roy, M.D., Véronique Brulotte, M.D., M.S., Manon Choiniere, Ph.D., Olivier Verdonck, M.D., M.S., Louis-Philippe Fortier, M.D., M.S., Philippe G. Richebe, M.D.,Ph.D.
Universite de Montreal, Montreal, Quebec, Canada
Disclosures: E. Renaud-Roy: None. V. Brulotte: None. M. Choiniere: None. O. Verdonck: None. L. Fortier: None. P.G. Richebe: Honoraria; Self; member of the advisory board for Medasense LTD, the manufacturer of the PMD200, since 2015.
Introduction: One challenge of today's anesthesiologist is to reach optimal hypnosis, analgesia and paralysis to provide safe general anesthesia (GA) with rapid recovery. Unfortunately, vital signs monitoring and minimal alveolar concentration provided by anesthesia stations lack precision to titrate medication. Moreover, under or over treatment result in adverse events for patients. Advanced monitoring with NOL index offers a more precise analgesia monitoring (PMD-200TM Monitor, Medasense, Israel) while Bispectral index (BISTM, Medtronic, USA) assesses hypnosis. Although improved safety with BIS has been published, combining BIS and NOL to improve patient outcomes has not yet been studied. We hypothesized that perioperative safety and recovery would improve when both depth of analgesia and anesthesia are monitored versus control group.

Methods: After REB approval (#CER15083), patients on Enhanced Recovery After Surgery program (colorectal surgery) equipped with low thoracic epidural were randomized to group Monitored (M: BIS+NOL) or group Control (C). Baseline Mean Arterial Pressure (BMAP) was assessed before incision. In group M, remifentanil infusion was guided for 10<NOL<20. Desflurane was targeted for 40<BIS<60. Phenylephrine infusion was used to maintain MAP +/- 10% of BMAP or to stay above 65 mmHg. For group C, anesthesiologist was blinded to BIS+NOL values. Remifentanil and phenylephrine infusions were used to maintain MAP within a range of +/- 10% of BMAP or above 65mmHg and desflurane concentration was set to 0.8 MAC. All data were electronically recorded every 5sec. Statistical analysis was done using T-test for means or Mann-Whitney for medians. Correlation calculations used Spearman Rank’s. Registration: NCT#03410485.

Results: Interim analysis was performed on the first 30 patients. M group showed decreased desflurane consumption (p=0.006), faster extubation time (p=0.028) and faster time to Post-Anesthesia Care Unit (PACU) Aldrete-score > 9 (p=0.046) meaning faster discharge from PACU. Time with BIS < 40 (p=0.075), phenylephrine consumption (p=0.18), hypotension time MAP < 80% of BMAP (p=0.53) and MAP < 55 mmHg (p=0.17) show a trend for better safety profile in group M but most of these criteria did not reach significance at this stage of the study. Non-significant longer time with MAP > 110mmHg (p=0.12) was observed in group M and remains less than one minute on average per hour of surgery in clinically acceptable ranges for laparoscopic surgery in Trendelenburg position. In PACU, pain scores at arrival were correlated with intraoperative remifentanil consumption (rho=0.736, p < 0.001) and at 90 minutes showed statistically significant improvement in group M (p=0.04) with less pain than group C. Other outcomes in PACU such as sedation, analgesia requirement, postoperative nausea and vomiting did not vary significantly between groups at this stage of the study.

Discussion: GA conducted with a combined BIS+NOL monitoring had significant impact on recovery outcomes with faster extubation, better pain scores at 90 minutes and quicker discharge from PACU. Combined monitoring BIS+NOL show a trend of improved intraoperative safety when focusing on hemodynamic parameters but did not reach significance at this stage of the study. Intraoperative nociception monitoring and opioid administration guidance with the NOL index seems to offer a better pain profile in PACU after colorectal surgery.
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