The Effect Of Propofol Of Different Plasma Concentrations On Sevoflurane MAC During Gynecological Laparoscopy Surgery

Study Background and PurposeAt present, endotracheal intubation general anesthesia is the most common way in laparoscopic surgery. It can effectively prevent visceral traction and discomfort caused by CO2 pneumoperitoneum during intraspinal anesthesia .It can guarantee the lung ventilation and is easy to control intraoperative respiratory and circulatory functions . Propofol and sevoflurane are commonly used in general anesthesia for laparoscopic surgery ,but the relevant studies on the interaction between the two drugs are less. It is necessary to study the effect of propofol on sevoflurane MAC and the relationship between them.It will help further clarify their pharmacological properties, and contribute to the use of reasonable compatibility and reduce the side effects when they are used longly.In this study, the index of response entropy (RE) was used as a criteria of the depth of anesthesia [1].We observed the effect of propofol in the different plasma concentrations on sevoflurane MAC and looked for the optimal plasma concentrations of propofol and sevoflurane MAC in order to provide reference for the clinical use.Data and MethodsChoose 75 patients undergoing selective gynecologic laparoscopic surgery, without significant heart,lung,liver and kidney disease, ASA gradeⅠ～Ⅱ, age 18～43-year-old. Using random sample method, in accordance with the intraoperative different propofol plasma concentrations, the patients were divided into A, B, C, D, E groups, plasma concentrations followed by 0.5μg/ml,1.0μg/ml,1.5μg/ml,2.0μg/ml and inhaled sevoflurane alone (no use propofol group), a total of 15 cases in each group.The informed consent was signed before the day of operation. Patients in each group were preoperative fasting 8 hours. Luminal sodium 0.1g im was given preoperatively. Upper limb vein was intravenously injected in the operating room.Routine monitoring of non-invasive blood pressure (NIBP),pulse oxygen saturation (SpO2),heart rate (HR),mean arterial pressure (MAP) and the entropy index (RE and SE) , basic values (T0) of HR and MAP were recorded. The patients of each group were induced by fentanyl-3.0μg/kg and propofol target-controlled infusion on 4.0μg/ml plasma concentrations . At the same time, assisted ventilation was used by mask at oxygen flow 3L/min. When patients on alert / sedation (OAA / S) score≤1[2], the intravenous injection of rocuronium 0.6mg/kg was given. The four train stimulation (TOF) monitoring of muscle relaxant status was used .When (TOF) T4/T1=0 , the tracheal intubation was performed. Intubation more than two times or difficult intubation was excluded from the experiment. After the success of intubation, intermittent positive pressure breathing was used. Gas analyzer was used to monitor the values of sevoflurane MAC and end-tidal CO2 partial pressure (PETCO2), controlling VT =8～10ml/kg,R=12～14 times / min,respiratory ratio of 1:2,the oxygen flow rate of 2.5～3L/min,PETCO2 for 35～45mmHg. When PETCO2 was continuously higher than 55mmHg last 5min, the patients were excluded from the experiment.From the insertion of laparoscopic to abdominal closure period, sevoflurane concentration was regulated to maintain the RE value at 35 ~ 50. Vasoactive drugs were used to maintain blood pressure on fluctuations less than 15% of basic values. Continuous monitoring of TOF was used. If there had a twitch, rocuronium 0.3mg/kg was given. Value beyond the basic heart rate of 15%, the additional fentanyl 1.0μg/kg was given. Value below the basic heart rate of 15%, the additional atropine 0.25mg / time was given. On the time of removing tumor,tubal ligation or stoma, muscle relaxants were stopped; when peritoneal washing, stopped the inhalation of sevoflurane; when sewing leather, stopped the infusion of propofol. If the operation time was shorter than 30min (including 30min), the data was excluded from the experiment. When the spontaneous breathing of patients restored, atropine 0.01mg/kg and 0.02mg/kg neostigmine antagonism were used. Oxygen flow to 5L/min was given to speed up sevoflurane from the intrapulmonary. When the patient breathing on his own to reach VT≥300ml, R≥12 times / min, SpO2≥95% in respiratory air and the RE at 80 ~ 90 ,the endotracheal tubes were extubed.The values of sevoflurane MAC were recorded respectivly at the beginning of surgery (T1), after pneumoperitoneum 15min (T2), after removing tumor,tubal ligation or stoma completed (T3), rinse after intraperitoneal (T4), when abdominal closure (T5 ). After control of breathing, the values of MAP and HR were recorded .The dosage of atropine and ephedrine were recorded and the average dosage was calculated in each group.The time from the pull-out laparoscopic tube (operation completed), respectively, to restoring spontaneous breathing,openning eyes,extubating endotracheal tube,calling his and her birthday,leaving operation room was recorded. Postoperative follow-up: the number of cases was recorded if awareness and bad memory or postoperative nausea and vomiting happened.All data was analyzed by statistical software SPSS14.0. Measurement data was expressed by mean±standard deviation ( x±s). Data comparison within groups was used by one-way ANOVA. Data comparison between groups was used by repeated measured analysis of variance. The interaction between sevoflurane and propofol was analyzed by the linear regression and correlation analysis. Count data was analyzed byⅹ2 test, P <0.05 considered that there was a significant difference.Results1.The general situation in the five groups: patients′age,weight and operative time were not significantly different (P> 0.05).2.There was not significant different in MAP and HR between the five groups(P> 0.05). The values of MAP within group A , T1 and T5 moment were significantly higher than that at T0(P <0.01). The values of MAP within group B, C and D , T1 and T5 moment were higher than that at T0(P <0.05). The values of MAP within group C , T2 moment was higher than that at T0(P <0.05). The values of MAP within group E, T5 moment was higher than that at T0(P <0.05). There were no significant difference in group A,B,C and D comparing with basic values of HR during surgery(P> 0.05). The values of HR in group E at the T1,T2,T3,T4 moment were significantly lower than that at T0(P <0.05). There was no significant difference with HR between T5 and T0 in group E(P> 0.05). 3.There were no significant difference in the values of sevoflurane MAC between group A and group E at the T1, T2, T3 moment (P> 0.05); the values of sevoflurane MAC in group A was lower than that in group E at the T4 moment (P <0.05). The values of sevoflurane MAC at the T1, T2, T3, T4 moment in the group B,C,D were significantly lower than that in group E respectivly (P <0.01). There were no significant difference with the values of sevoflurane MAC between the five groups at the T5 moment (P> 0.05). Between the values of sevoflurane MAC and the plasma concentrations of propofol,it showed a linear relationship. linear regression equation was Y = 0.752-0.140X, r =-0.979.4.The average consumptions of atropine in group C was significantly increased than that in group E (P <0.05); the average consumptions of ephedrine were not significantly different between the five groups (P> 0.05) .5.In the times from the extubation of laparoscopic tube (operation completed), respectively, to restoring spontaneous breathing,openning eyes,extubation of endotracheal tube,calling his or her birthday,leaving operation room, there were no significant difference between the five groups(P> 0.05).6.There had no awareness and bad memory found during the surgery. The incidence of postoperative nausea in group A, B, C, D was significantly lower than that in group E (P <0.05). The incidence of vomiting between group B and group C was significantly lower than that in group E (P <0.05).Conclusion1.In sevoflurane inhalation anesthesia, supplemented with different plasma concentrations of propofol target-controlled infusion during gynecological laparoscopic surgery, the values of sevoflurane MAC showed dose-dependently reduced with the increase of propofol plasma concentrations. Plasma concentration of 0.5μg/ml propofol maybe equivalent to 0.01 MAC sevoflurane; plasma concentration of 1.0μg/ml propofol maybe equivalent to 0.13 MAC sevoflurane; plasma concentration of 1.5μg/ml propofol maybe equivalent to 0.19 MAC sevoflurane; plasma concentration of 2.0μg/ml propofol maybe equivalent to 0.30 MAC sevoflurane.2.Sevoflurane inhalation anesthesia supplemented with different plasma concentrations of propofol target-controlled infusion, can reduce the amount of sevoflurane and maintain an appropriate depth of anesthesia and avoid awareness and memory during surgery. It can awake quickly. Sevoflurane supplemented with 1.0μg/mL or 1.5μg/ml plasma concentrations of propofol can significantly decrease the incidence of postoperative nausea and vomiting, compared with the simple inhalation of sevoflurane anesthesia.