Study Of Remifentanil-Propofol Total Intravenous Anaesthesia

IntroductionTCI (target controlled infusion) technique represented the newest development of TIVA (total intravenous anesthesia ). The bispectral index ( BIS ) and auditory evoked potential index (AAI) were proposed as a measure of anesthetic depth. The BIS may nave the original place in the aspects of judging consciousness. However the AAI was a more sensitive predictor of patient response to the pain stimulations than the BIS.Remifentanil and Propofol are fitted to apply to long - term TCI without prolong the wake - up time. Especially the special metabolism characteristics of Remifentanil makes it be able used for the patient of the liver kidney function obstacle and other special crowds safely.The purpose of this research is to study the depth of TIVA with Remifentanil and Propofol , and hymodynamic changes , other adverse events , to compare the differences between BIS and AAI reflecting different aspect of anaesthesia. And to make an clinic evaluation of TCI system which was not designed for Chinese people.MethodsForty patient scheduled for elective orthopedic operation participated in the study after given informed consent. They ,ASA Ⅰ ~ Ⅲ , are divided into group Ⅰ ( <65yr) and group Ⅱ ( ≥65yr) according to the age, twenty for per group.After a 5 ml/kg Lactated Ringer' s solution infusion and preoxygenation, Remifentanil 1.0 ng/ml (effect site concentration) was administered ,then in-creased by 1.0ng/ml to 4. 0 ng/ml. After that Propofol TCI administered with 1.0 μg/ml ,increased by .1.0 μg/ml to 4.0μg/ml. The target concentration of Remifentanil and Propofol decreased to 3.0 ng/ml, 3.0 ug/ml after intubation. The anesthesia maintained by TIVA with Remi and Prop. During the whole procedure, monitor SBP, DBP, HR, SpO2, AAI, BIS and record the index of different time including T1(baseline) T2(Remi induction)T3(Propofol induction) T4(intubation)T5(skin incision)T6 (extubation) and the index changes, such as △MAP, △HR, △BIS, △AAI. Monitor and compare the number of Isoflu-rane using times, the times of change Propofol target concentration , the dosage of Atropine , Ephendrine, Fentanyl. Compare the time to spontaneous breathing, eye opening, first verbal command , extubation and VAS grads, the first time to Aldrete score≥9, total dosage of two drugs. Record the predictive concentration of Remi and Prop of different time and study the relashionship between BIS, AAI and MAP,HR, target concentrations .All statistical analysis were performed by using SPSS11.5. Comparisom between groups was performed with T - test. X2 - test were used to compare the proportion of patient measurement. In addition , the relationship between Remifentanil and Propofol target concentrations and BIS, AAI and MAP , HR were analysed by pearson's coefficient of correlation. A level of P <0. 05 was considered statistically significant .ResultsIn all patient, BIS and AAI values were significantly decreased during Remifentanil induction period. At T2,T3 changes in BIS values in group bigger than in group . In period of Propofol induction, MAP AAI and BIS values decreased. HR in group I increased . At LOC time, Propofol target concentrations were 2.5 ±0.7 g/ml( Ⅰ ) ;1.2 ±0.5 g/ml( Ⅱ ) . Remifentanil effect site concentrations were 3.5 ±0. 4ng/ml( Ⅰ ) ;3. 3 ±0. 4ng/ml( Ⅱ ). After induction , MAP decreases of two groups did not exceed normal limitations.The frequency of adverse events of two groups were no statistical differences . The time to spontaneous respirations and eye opening , recovery of response toverbal command, tracheal extubation, and time to first Alderete score ≥9 of group I were statistically earlier than of group Ⅱ. The predictive ability of consciousness of BIS was 90.4% and 55% for AAI. However the predictive ability of harmful stimulation were 75% for AAI, 62.5% for BIS. The relation coefficient between BIS values and target concentrations of Propofol are bigger than between AAI. And the AAI was versely correlated with target effect site concentrations of Remifentanil . The relativity between A AAI and between A MAP was more close than A BIS and A MAP.DiscussionAnesthesia with Remifentanil - Propofol by TCI system can provide satisfied anaesthesia depth for the orthopedics surgical operation. It can provide low occurrence rate of adverse events , quick wake up, at the same time can avoid many adverse effects of traditional intravenous anesthesia. It also can safely used in older patients.The BIS and AAI all can reflect the painful information of anaesthetic composition. Among them the AAI varied more in time. So the AAI was more intelligent evaluation in painful information and it's relativity between Remifentanil effect - site concentration can explain more informations from painful stimulations. Whereas, the BIS values correlated with hypnotic drug concentrations was a good indicator of consciousness.Conclusions1. Anesthesia with Remifentanil Propofol by TCI system can provide satisfied anesthetic depth for the orthopedics surgical operation.2. Remifentanil Propofol total intravenous anaesthesia can provide low occurrence rate of adverse events , quick wake up characteristics, at the same time can avoid many adverse effects of traditional intravenous anesthesia.3. Anesthesia with Remifentanil Propofol by TCI system can safely used in older patients.