The Clinical Application Of Target-controlled Infusion Of Propofol And Remifentenil In Patients Undergoing Partial Hepatectomy Under General Anesthesia Combined With Epidural Block

Part OneThe clinical application of target-controlled infusion of propofol in patients undergoing partial hepatectomy under general anesthesia combined withepidural blockObjective To evaluate the clinical effect and predictive performance of Diprifusor target-controlled infusion system for propofol in patients undergoing partial hepatectomy during epidural blockade under general anesthesia.Meanwhile to evaluate the predicted probability of effect-site EC ,BIS,and AAI at loss of consciousness and recovery in this kind of patients.Methods Twenty-four ASA I - II patients aged 18-65 scheduled for elective surgery under combined general and epidural blockade anaesthesia were divided into 2 groups according to the category of surgery:controlled group (C group,undergoing convention upper abdominal surgery,n=12) and hepatectomy group (H group,undergoing partial hepatectomy,n=12). Anesthesia was induced with fentanyl 4ug/kg and propofol by TCI at a target plasma concentration of 3ug/ml. Epidural block combined propofol target-controlled infusion of 3ug/ml was used throughout the operation.MAP,HR,ECG,SpO₂,bispectral index(BIS) and auditory evoked potentials index(AAI) were monitored before and during anesthesia.The changes in BP,HR,BIS,AAI , time of loss of consciousness and emergence from anesthesia were recored.Relationship between BIS,AAI and effect-site EC50 for propofol at two clinical endpoints was calculated by logistic regression analysis.Arterial blood samples were taken at base line,loss of consciousness, 10,20,30,60,90,120min after induction of general anesthesia and emergence from anesthesia.Plasma propofol concentrations were determinated by reversed-phase high-performance liquid chromatography with fluorescence detection.The individual and pooled bias [median performance error(MDPE)],inaccuracy[median absolute performance error(MDAPE)] and wobble of the propofol TCI device were determined from the pooled and intrasubject performance errors.Results (1)There is no significant difference in the age,weight,basal BIS and AAI between the two groups except that the ALT level of H group exceeded that of control group before the operation(P<0.05).There is no significant difference in changes of HR,MAP,BIS,AAI between the two groups during the operation. (2)The time of loss of consciousness is shorter than that of control group (P<0.05).There is no significant diffence in the time of emergence between the two groups. (3)The effect-site EC₅₀S of propofol of two groups are 1.95ug/ml, 1.61ug/ml respectively for loss of consciousness. The effect-site EC₅₀S of propofol of two groups are 1.28ug/ml, 1.11ug/ml respectively for the emergence from anesthesia. The effect-site EC50S of propofol of H group is lower than that of control group (P<0.05).Bis₅₀s of loss of consciousness of two groups are 66.99,72.05 respectively. Bis₅₀ of loss of consciousness of H group is higher than that of control group(P<0.05).AAI₅₀s of loss of consciousness of two groups are 39.45,38.97 respectively. Bis₅₀S of two groups for emergence from anesthesia are 76.31,76.00 respectively. AAI₅₀S of two groups for emergence from anesthesia are 69.50,72.80 respectively . There is significant difference in predicted probability of effect-site EC and BIS at loss of consciousness between two groups(P<0.05). There is significant difference in predicted probability of effect-site EC of propofol at emergency from anesthesia between two groups(P<0.05).(4)A total of 180 blood samples are analysed.Pooled MDPE,MDAPE and wobble of Diprifusor TCI device are 11.93%, 17.89% and 13.09% respectively. Conclusions (1)The effect-site EC₅₀S of propofol for loss of consciousness and emergence from anaesthesia in patients undergoing partial hepatectomy are decreased significantly. Such patients may be more sensitive to the depressant effects of propofol administered by target-controlled infusion.(2)There is significant difference in predicted probability of effect-site EC and BIS at loss of consciousness between two groups of patients. There is significant difference in predicted probability of effect-site EC of propofol at emergency from anesthesia between two groups.(3)Propofol can be administered by TCI with acceptable bias and inaccuracy.The predictive performance of Diprifusor TCI system is considered acceptable for the patients under general anesthesia combined with epigural block.Part TwoThe clinical application of target-controlled infusion of propofol and remifentenil in patients undergoing partial hepatectomy undergeneral anesthesia combined with epidural blockObjective To study the linical effect and predictive performance of target-controlled infusion of propofol and remifentenil in patients undergoing partial hepatectomy under general anesthesia combined with epidural block. Methods Thirty-six ASA I - II patients aged 18-65 undergoing elective partial hepatectomy under general anesthesia combined with epidural block were enrolled in this study.Anesthesia was induced with TCIs of remifentanil and propofol.The patients were randomized to divided into 3 groups (n=12) and given remifentanil with target concentration 2,4,6ng/ml respectively .The target plasma propofol concentration was set at 3ug/ml in all patients .The patients were intubated when the patients fails to respond to verbal command and eyelash reflex was lost.Tracheal intubating was facilitated with succinylcholine 1mg/kg.MAP,HR,ECG,SpO₂,BIS,AAI were monitored before and during anesthesia.Blood samples were taken for determination of arterial propofol and remifentanil concentration by reversed-phase high-performance liquid chromatography with fluorescence detection and liquid chromatography-mass spectrometry detection (LC-MS/MS) respectively.The pharmacokinetic parameters of propofol and remifentanil administered by TCI were set with reports of Marsh and Minto respectively.Performance of TCI devices was determined by the median performance error(MDPE),the median absolute performance error(MDAPE)and the wobble.Results (1)The time for loss of consciousness of 2ng/ml remifentanil group is longest among three groups(P<0.05). The patients of 4ng/ml remifentanil group during intubation is of less BP and HR changes compared to pre-intubation . The patients of 6ng/ml remifentanil group required more atropine compared to 2,4ng/ml groups.(2)There is no significant difference on the MAP,HR,BIS,AAI among three groups during the sustaining period of anesthesia.The values of BIS are kept at 41.7 ± 10.74 and the values of AAI are kept at 16.19 ± 6.71.(3)There is no significant difference on the recovery time,HR,MAP,BIS,AAI among three groups . The values of BIS and AAI for emergence from anesthesia are 80.9 ± 9.0,68.67 ± 17.36 respectively.(4)A total of 432 blood samples are analysed .Pooled MDPE,MDAPE and wobble of propofol TCI device are 20.95%,24.93%,10.80% respectively .Pooled MDPE,MDAPE and wobble of remifentanil TCI system are -5.15%,21.29%,14.34%.Conclusions (1)The study confirms the safety and effect of target-controlled infusion of propofol and remifententenil in patients undergoing partial hepatectomy under general anesthesia combined with epidural block.The method provides the neurovegetative protection with good hemodynamic stability and absence of major side effects.The use of epidural analgesia appears to offer a reasonable treatment option that provides adequate pain control at recovery from general anesthesia and the period of postoperation.(2)The anesthesia was satisfactory in all patients.Remifentanil and propofol can be administered by TCI with acceptable and inaccuracy.The predictive performance of propofol and remifentanil TCI system is considered acceptable for clinical purposes in patients undergoing partial hepatectomy under general anesthesia combined with epidural block.