The Study On Rational Compatibility Of TCI Propofol And Remifentanil Under BIS Monitoring For Induced Abortion

ObjectiveThe study aimed to investigate the optimal combination concentration oftarget-controlled infusion (TCI) propofol and remifentanil for induced abortion, to providesome beneficial data for induced abortion with propofol and remifentanil.MethodsIn the first part of the study, 10 ASAâ… female patients, aged 18～35 years old, withthe body mass index between 18 and 25kg/m², who volunteered to received generalsurgery under general anesthesia were asked to take part in the study. The anesthesia wasinduced with a TCI of propofol starting at the target of 0.5μg/ml; this was followed by astepwise increase in TCI with each step increase amounting to 0.3μg/ml and changed thestep increase amounting to 0.1μg/ml when ECp was up to 2.0μg/ml. Bispectral index (BIS)value, the observers' assessment of alertness/sedation scale (OAA/S) and vital signs wererecorded at every ECp until the patient was loss of consciousness. The mean ECp and BISvalue were calculated at the point of loss of verbal contact (LVC) and loss of response (LOR).The correlation between ECp and BIS value were analyzed.In the second part of the study, 100 ASAâ… female patients, aged 18～35 years old,with the body mass index between 18 to 25kg/m², who volunteered to received pregnancytermination under general anesthesia were asked to take part in the study. Patients wereenrolled if they had been final diagnosed as intrauterine pregnancy with 6～10 weeks aftersome examinations. 100 patients were randomly allocated into five groups. All patientswere to receive ECp at 5.6μg/ml and the effect-site concentration of remifentanil at0.9,1.1,1.4,1.8,2.2ng/ml respectively in each group. The numbers of patients whoaccomplished the surgery successfully and who had respiratory depress were recorded. TheEC_R50, RC_R50 and TI which were calculated by the probit analysis were compared with the corresponding data of remifentanil when combined with 4.5μg/ml and 5.2μg/ml propofol, whichwere determined in the other studies accomplished by Dr. Lihua and Dr. Kanglirespectively.ResultsIn the first part of the study, the mean ECp of LVC and LOR for young women were2.47±0.36μg/ml and 2.63±0.31μg/ml respectively, and the mean BIS value were 56.1±5.53and 49.9±4.63 respectively. Good correlations between ECp and BIS value (r=-0.937),between ECp and OAA/S scales (r=-0.810) and between BIS value and OAA/S scales(r=0.896) were noted.In the second part of the study, the patients had no significant difference on thegeneral characteristics. The EC_R50, RC_R50 and TI were 0.68ng/ml, 2.0ng/ml and 2.94respectively. Good correlation between BIS and arousing time was noted.ConclusionBIS monitoring can help anesthetist to know the sedation depth of TCI with propofoland to know anesthesia depth and arousing time of induced abortion with propofol andremifentanil. Compared with the remifentanil effect-site target controlled infusioncombination with 4.5μg/ml or 5.2μg/ml propofol, there were higher TI and better safetywith 5.6μg/ml propofol. Concerning respiratory depression, the combination with higherconcentration of propofol and lower concentration of remifentanil is more feasible inpractice.