Abstract PR603

Abstract

Background & Objectives: Total intravenous anesthesia is an anesthetic technique that can be administered with TCI (target controlled infusion) or closed loop systems. The authors designed an automatic controlled system using fuzzy logic with clinical variables such Bispectral Index (BIS), heart rate and blood pressure. The aim of this study was to evaluate the clinical and technical performance of this controller compared with a conventional TCI system in patients who undergoing general surgery under anesthesia in an University Hospital, Medellin, Colombia. Materials & Methods: It was a controlled, randomized, single-blind study in which 150 surgical patients were assigned two groups: 75 patients were into TCI group and 75 patients were into closed loop with BIS. The clinical performance was determined according to the mean surgical time in range of BIS between 40-60. In addition, the proportion of patients with more than 80% of the surgical time with BIS between 40-60 (it was considered optimal), patients with adequate intra operative analgesia as measured by the analgoscore between -3 and +3. The technical performance of the controller was determined by MDPE, MDAPE, wobble. Results: For the primary outcome the mean time of BIS 40-60 for the closed loop group was 75.24% (SD 15.78) vs 59.5% (SD 20.3) for the TCI system, with an absolute difference of 15.8%, IC 95%: 9.9% to 21.65%, p <0.0001. The proportion of patients with more than 80% of surgical time with BIS 40-60 in closed-loop group was 48% vs 17.3% in TCI (RR 2.78, IC 1.60 - 4.78, p = 0.0001) (seefigure 1). The mean time for adequate intraoperative analgesia was 82.4% (SD 25.1) for closed loop and 70.77% (SD 32.8) in TCI, with an absolute difference of 4.76, IC 95%: 2.23 to 21.06, p = 0.016. The technical performance for closed loop controller was better than TCI systems (MDPE -11,05 vs -3,33, p=0,0001; MDAPE 15,57 vs 11,47, p = 0,0001). There was no difference in the proportion of awakening or intra operative movement. No intraoperative recall episodes was reported.Conclusion: The closed-loop system was better than a TCI system to maintain BIS between 40-60 during a general anesthetic.