Feasibility Of BIS Guided Closed-Loop Anesthesia Delivery System In The Laparotomy For Elderly Patients With Gastrointestinal Tumor

Objective: The study was aimed at evaluating the feasibility of BIS guided closed-loop anesthesia delivery system?CLADS? in the laparotomy for elderly patients with gastrointestinal tumor.Methods: 60 cases of patients undergoing elective open gastrointestinal tumor resection, male or female, aged from 65 to 75 years, BMI:18²5 kg/m2, ASA?, were randomly allocated to 2 groups: a CLADS group? Group C? and a open-loop group? Group O? by random number table method, 30 cases in each. The operations is performed by the same team of surgeons. After the patients entered into the operation room, SpO₂, ECG and HR is monitored. Radial artery cannulation after local anesthesia, then connect the FloTrac sensor, CO, CI, SV, SVV were monitored. ECG-guided puncture with catheterization by right internal jugular vein. Intravenous injection of sufentanil 0.3?g/kg, the anesthesia with TCI of propofol, initial Cp: 1.5ug/ml. Induction of anesthesia increased gradually, the concentration increase of 0.5 ug/ml for one step. After loss of consciousness, intravenous injection of cisatracurium 0.2mg/kg. Mechanical ventilation after intratracheal intubation. Maintenance of anesthesia: In Group C, using the automatic adjustment of propofol target controlled concentration based on monitoring of BIS, BIS was maintained between 45 to 55. 30 min before the end of surgery, stop the closed-loop target controlled infusion, and reduce the target concentration of propofol gradually. In Group O, using the manual adjustment of propofol target controlled concentration based on monitoring of BIS, BIS was maintained between 45 to 55. Target controlled infusion of remifentanil?Cp2⁸ng/ml? in two groups. Intermittent intravenous injection of cisatracurium maintain muscle relaxation. 15 min before the end of surgery, intravenous oxycodone 0.1 mg/kg, at the same time connect patient-controlled intravenous analgesia pump, drug preparation for oxycodone 0.75mg/kg, diluted with saline to 100 ml, background infusion of 2 ml/h, PCA dose 0.5 ml, lock time 15 min. Before the end of surgery and 3min respectively, stop infusion of propofol and remifentanil.MAP, HR, CO, SV, CI and BIS were recorded at before induction?T0?, before intubation?T1?, intubation?T2?, 3min after intubation?T3?, skin incision?T4?, 30 min after skin incision?T5?, 60 min after skin incision?T6?, 90 min after skin incision?T7?, 120 min after skin incision?T8?, end of operation?T9?, and the time of extubation?T10?. SVV is recorded from T3 to T8. CVP is recorded from T4 to T10. Test the lactate in T0, T7 and T9; Recorded the duration of anesthesia, the duration of operation duration. Recorded the total dosage of propofol and remifentanil. The incidence of hypertension?30% higher than baseline? and hypotension?30% lower than baseline? were recorded in the two groups. The amount of infusion quantity, the amount of liquid crystal, the amount of colloida, lintraoperative blood loss, and urine output were registered. Accumulate low BIS? BIS<45? time and the percentage of accumulate low BIS time were registered; Recorded the recovery time, extubation time and orientation recovery time; Recorded intraoperative awareness; Ambulation time, time to first flatus and discharge time were registered. Postoperative complication and 30-day mortality were registered.Results: Compare to Group O, the total dosage of propofol decreased, and remifentanil increased in group C. The frequency of hypertension was increased in group C. The frequency of hypotension was decreased in group C. Accumulate low BIS?BIS<45? time and the percentage of accumulate low BIS time both were decreased in group C. The recovery time, extubation time and orientation recovery time were shortened?P<0.05?.There were no intraoperative awareness in any group?P>0.05?. There were no significant diffierences in ambulation time, time to first flatus and discharge time between the two groups?P>0.05?.Conclusion: BIS guided closed-loop anesthesia delivery system?CLADS? can safely and effectively applied in the laparotomy for elderly patients with gastrointestinal tumor, and it can save the dosage of propofol.