Effect Of BIS-guided Anesthesia Depth On The Recovery Of Patients Undergoing Partial Hepatectomy

Objectives:Many previous clinical trials have shown that BIS monitoring depth of anesthesia can reduce anesthetic dosages and accelerate patient recovery. This study was designed to test the effect of BIS-guided anesthesia depth on the recovery of the patients undergoing partial hepatectomy and investigate the application and significance of BIS monitoring in anesthetic management of these patients.Methods:This study was a prospective, randomized, single-blind controlled clinical trial.50patients, ASA physical status Ⅱ-Ⅲ, aged30-60years old, scheduled to undergo elective liver resection, were enrolled in this study. The patients were randomly divided into two groups:BIS monitoring group (B group, n=25) and clinical judgment group (C group, n=25). The B group had anesthesia adjusted to maintain a BIS value between40and60during maintenance of anesthesia. C group had BIS measured but not revealed to attending anesthesiologists. Anesthesia was adjusted according to traditional clinical signs and hemodynamic parameters.Both groups were induced by intravenous midazolam0.1mg/kg,0.5ug/kg sufentanil, CIS atracurium0.15mg/kg, propofol was infused1.5-2.5ug/ml using a target controlled infusion system(TCI) and the initial target concentration was setted at1.5ug/ml, increase0.5ug/ml per minute until the patients lost consciousness. In group C, after loss of eyelash reflex and adequate jaw relaxation, tracheal intubation was determined based on clinical judgment. In group B, when the BIS value was sustained for1min at50±5, the patients were intubated. Anesthesia was maintained with propofol-remifentanil-atracurium.In group B, anesthetic dosage was adjusted to achieve a BIS value between40and60. In group C, anesthetic drug administration was titrated according to clinical judgment. Keep arterial pressure within20%of the baseline and the heart rate within50to90beats/min range in both group. After closing the peritoneum, stop using cis-atracurium and inhalation anesthetics in both group. Reduced drug dosage based on clinical experience in group C and adjusted anesthetic dosage to achieve a BIS value between55and65in group B. In both groups, cessation of propofol can begin since suturing the skin and small dose remifentanil was administered until the end of the operation. When the surgery finished, stop all the anesthetic drugs, this moment as the beginning of the recovery. Patients were observed in post-anesthesia monitoring treatment room(PACU) to continue to monitor the BIS value. After the recovery of spontaneous breathing, intravenously inject atropine0.5mg,1mg neostigmine to antagonize residual muscle relaxant effect. Pull out the tracheal catheter when the patient reached extubation criterion. After extubation, continued to observe in PACU until modified Aldrete score was9or more.24hours after surgery, patients were regularly reviewed to determine whether intraoperative awareness happened.Before anesthesia induction, one minute before intubation, one minute after intubation, recorded heart rate, noninvasive blood pressure, arterial oxygen saturation, respiratory rate, and bispectral index value of the patients. During operation, hemodynamic variables were recorded in5-mimute intervals, BIS values was recorded in1-mimute intervals, medication, anesthesia time, operation time and blocking time were also recorded. In the postoperative recovery period, we recorded the recovery times from the end of anesthesia to eye opening, extubation, mandatory action, orientation and Aldrete score≥9and the corresponding BIS values. Observer’s assessment of alertness/sedation(MOOA/S) were assessed. Time needed to reach MOOA/S1,2,3,4points and the corresponding BIS values were recorded.Results:1. Dosages of Sufentanil, midazolam, atracurium, sevoflurane and remifentanil between two groups show no difference(P>0.05), and propofol consumption in group B was significantly lower than in group C (3.03±1.00vs5.30±1.49, P<0.05); 2. Dosages of esmolol, atropine and dopamine between two groups show no significant difference (P>0.05), and dosage of labetalol in group B was significantly higher than in group C (28.5±25.8vs12.0±17.4, P<0.05);3. Mean intraoperative BIS value in group B was significantly higher than group C(44.8±4.2vs38.3±10.4, P=0.009); Ratio of Bis index between40and65in group C was significantly lower than in the group B (43.4%vs85.3%, P=0.000); Ratio of BIS<40in group C was significantly higher than in group B(54.8%vs13.5%P=0.000.); Ratio of BIS>65in group C was significantly higher than group B (2.0%vs1.2%, P=0.002); Ratio of BIS values at30-40,20-30in group C was significantly higher than in group B (25.0%vs11.9%,25.2%vs1.6%, P=0.000); Ratio of BIS values at10-20and BIS<10in group C were3.3%and1.3%. BIS values of20-30and BIS<10did not exist in group B;4. Time to reach MOAA/S score1,2,3and4in group B is significantly shorter than in group C(P<0.05); Time to eye opening, extubation, mandatory action, orientation, Aldrete score≥9and cooperation score>2in group B was significantly shorter than in group C (P<0.05).Conclusions:1. In liver resection, the traditional administration of anesthesia in reference to clinical signs and hemodynamic parameters usually lead to deep anesthesia;2. BIS-guided anesthesia depth can reduce intraoperative propofol consumption and accelerate postoperative recovery of the patients undergoing partial hepatectomy.