Comparison Of Different Concentration Ropivacaine Epidural Anaesthesia Combined With General Anaesthesia Modulated By Bispectral Index In The Elderly

Objective To compare the effects of epidural anaesthesia with three differentconcentration ropivacaine on isoflurane requirements, haemodynamic variables,stress hormone response and the emergence from anesthesia during upper abdominalsurgery under combined epidural/general anesthesia by feedback from bispectralindex.Methods Sixty ASA classâ… -â…¡patients above the age of 65 scheduled forupper abdominal gastro-intestinal surgery were included in this study. Patients withanticoagulation, significant cardiorespiratory disease and psychiatric disorders wereexcluded. According to the epidural treatment, patients were randomly distributedinto four groups to receive ropivacaine 0.2%, 0.375%, 0.5% and normal saline byepidural with isoflurane general anaesthesia. Group A received epidural normalsaline (NS) + isoflurane anesthesia. Group B received epidural 0.2% ropivacaine +isoflurane anesthesia. Group C received epidural 0.375% ropivacaine +isofluraneanesthesia. Group D received epidural 0.5% ropivacaine +isoflurane anesthesia.Isoflurane was adjusted to achieve a target BIS of 50~60 during maintenance ofanaesthesia. Measurements included the inspired (FIiso) and end-tidal isofluraneconcentrations (FE'iso), blood pressure (BP), and heart rate (HR) before surgery andevery 5 min during surgery. Plasma samples were taken before induction, 1 and 2hours after surgery began for measurements of cortisol and interleukin-6. Theemergence times from anesthesia were recorded. Relalionships between time to eyeopening and BISfinal and FE'iso were compared to suggest which one is a betterpredictor during postoperative emergence from anaesthesia. Following recoveryfrom anaesthesia, the patients were questioned about explicit recall of intraoperativeevents, and the interview was repeated within 5h on the ward and the next day. Results Mean and change per 5min in FIiso and FE'ISO were significantly lowerand smaller respectively in Group C and D than in Group A (p<0.05). The totalisoflurane usage was 23% lower in the group D compared to the Group A (p<0.05).And Group C induces similar isoflurane-sparing effect by reducing 21% (p<0.05).Group C and D showed lower and less variable values of MAP when compared withGroup A. No significant differences were observed between Group A and B. Theplasma concentrations of cortisol and IL-6 were significantly higher after skinincision (T2-3) than the baseline value (T1). There was no significant difference inplasma cortisol concentration before (T1) and after skin incision (T2-3) in Group Cand D (P>0.05). The time to orientation was faster in the group D compared to the Agroup (p<0.05), None of the patients had recall of intraoperative events. Conclusions To maintain BIS value during combined epidural/general anaesthesiafor upper abdominal surgery in the elderly, 0.375% and 0.5% ropivacaine epiduralcombined isoflurane anaesthesia showed lower and less variable values of MAP,reduced isoflurane usages about 21% and 23% respectively, attenuate the plasmalevels of cortisol, IL-6 in response to surgical stress, facilitate early emergence fromanaesthesia. so ropivacaine0.375%,0.5% should be favored during combinedanesthesia in the elderly with BIS monitoring. And in addition, BIS was superior toFE'ISO in predicting recovery during postoperative emergence from combinedepidural and general anaesthesia.