The Application Of Remifentanil Combined With Propofol For Anesthesia Of Ophthalmic Surgery In Children

IntroductionThe analepsia time after operation in pediatric anesthesia is fairly difficult to grasp, especially the minor operation. The tracheal intubation and extubation increase the risk of anesthesia. As a short - action intravenous anesthetic, the pharmacokinetics and pharmacodynamics of remifentanil are as follows. Remifentanil undergoes rapid metabolism by nonspecific esterases within 1 min, and a rapid clearance and short terminal half - life that is independent of dose and of hepatic and renal function. Especially the pharmacokinetics of children is similar to the adults. It had been reported that remifentanil combined with propofol could be used in the anesthesia of induced abortion and some invasive examination with spontaneous breathing to decurtate the recovery time;This way can also be used in the short - term operation to decurtate the complications of the tracheal intubation and extubation. There are few investigations about the anesthesia with spontaneous breathing, it is necessary to make further investigation.The BIS value is commonly considered as one of the indexes to reflect the function of the cerebral cortex and used in the anesthesia depth evaluation to decurtate the recovery time. Ketamine had commonly been used in pediatric anesthesia before. While it can induce the adverse effects like cardio — vascular and psychiatric dysfunction. In addition, it had been reported by Sakai and Barr that the BIS value only decreased lightly after the intravenous injection of ketamine. The separation between anesthesia and cerebral electrical activity is conformed to the pharmacokinetics of ketamine. It was rarely reported that the BIS value had seldom been used as a monitoring device to conduct the dose of remifentanil.The selection of the suitable doses for different age children to meet the need of the operation without the respiratory inhibition and significant hemodyamics changes is focal point of our investigation.Our clinical experiment is to study the security, the feasibility and the individual difference of the continuously intravenous injection of remifentanil in the short - term ophthalmological operation in different age groups of the children, and discuss the suitable dosage of remifentanil and propofol by the continuously intravenous injection of remifentanil in the general anesthesia with spontaneous breathing in children through BIS.Materials1. Patients: Forty - eight children preparing for the short - term ophthalmological operation, ASA I II ,whose age varied from4 to 12 years old and body weight from 15 to 45 kilograms were selected without sex limit. The excluding standard: ( 1) cataracta glauca;( 2 ) central nervous system disease;(3 ) congenital disease;(4) hepatic and renal dysfunction. The operations of Squint correction ( single or double) , intraocular lens implantation, cornea repairing were included.2. Main drugs: Ketamine ( Jiangsu Hengrui Pharmaceutical Linited Company );Propofol ( AstraZeneca Pharmaceutical Limited Company );Remifentanil (Hubei Yichang Renfu pharmaceutical Limited Company).3. Main apparatus: All - round anaesthetic machine ( Detax Ohmeda7000 American);Multifunction monitor( Detax Ohmeda S/5 American) .-intravenous transfusion pump ( B. Braun micro - injection pump Germany );HXD—I type multifunction combination monitor(Heilung -kiang Huxiang Company).Methods1. The grouping: Forty - eight children preparing for the short - term ophthalmological operation, whose age varied from4 to 12 years old, were randomly divided into two groups according to the age, Group I (4 7 years old) , Group11(8 -12 years old) and 24 cases in each group. According to the two different anesthesia modes, each group was then randomly divided into the PK subgroup ( ketamine and propofol combination group) and the PR subgroup ( remifentanil and propofol combination group).2. Methodology2.1 All patients were monitored with continuous electrocardiograph, pulse oximetry and multifunction monitor for BIS value. All patients are accord to the Department of Anesthesia Guideline ( ^6 ⁸h for milk and food, ^3 ⁴h for clear liquids). Premedication of atropine 0. 02mg ? kg"1 was intramuscularly administered 30 minutes before operation. The spontaneous breath was maintained without tracheal intubation. Oxygen (2L ? min" )was given via face mark during the induction and the beginning of the operation. In the PK group the operation was started when there was no reaction during the eyeball wash, and in the PR group the operation was started when the BIS value was inferior to 70.2. 2 In the PK group 2mg. kg"1 ketamine and 2mg. kg "propofol were intravenously injected for the anesthesia induction. After the anesthesia induction, continuously intravenous injection of propofol at the rate of 6mg. kg"1. h-1and intermittent intravenous injection of ketamine at the dose of 1 2mg. kg were given;In the PR group the injection of ljxg ? kg" remifentanil was first given and then the anesthesia induction was started with the intravenous injection of 2 mg ? kg" propofol. The continuous intravenous infusion of remifentanil at the dose of 0. l|xg . kg"1, min"1 and propofol 6mg. kg"1. h^!were given for the beginning of maintenance of anesthesia. The infusion rate of remifentanil was increased by 0. 025 u,g. kg"1, min"1 per two minute until the operation operation was began.2. 3 During the anesthesia induction and operation, SpO2 was maintained^ 95%. According to the hemodynamic changes (the changes of SBP and HR ^ 10% ) and respiratory index ( RF^8 times/min) , in the PK group ,the infusion rate of propofol was adjusted by 1.5 mg. kg"1. h ^l. In the PR group the infusion rate of remifentanil was adjusted by 0. 025jmg. kg"1, min"1 or stopped and BIS was maintained between 60 and 70. After the adjustion of rate of remifentanil for five minute,the changes of SBP and HR still exceed 10%of fundament, the in-fusion rate of propofol was adjusted by 1. 5 mg. kg *. h '.3. Monitor indexThe times were designed as follows, T,, before the anesthesia induction, T2,1 minute after the anesthesia induction, T3, 3 minutes after the anesthesia induction, T4, the initiation of the operation, T5^T6>T7^T8, each five -minute interval after the initiation of the operation, T9, the anesthesia recovery after the operation. The systolic pressure ( SBP), diastolic pressure ( DBP), heart rate (HR) , respiratory rate ( RF) N SpO2 and BIS value were recorded. The infusion rates of propofol and remifentanil were recorded at each five - minute interval and each one — minute interval during the anesthesia induction. The incidence rate of the body movement and the oculocardiac reflex during the operation, the incidence rate of the restlessness, nausea and vomiting and nightmare after the operation were observed. The occurence of the respiratory inhibition and the changes of the respiratory frequency were also observed. Five children were respectively randomly chosen from the four groups for the blood — gas analysis in the end of the operation. The analepsia time, consciousness recovery time and total sedative time were recorded.Results1. General state: There were no significant difference of operation time, sex ratio and operation categories in the four groups ( p >0.05). Compared with the same age children in Group I and II, there were no significant difference of age and body weight(p > 0.05) .2. SBP^DBP^HR ,,RF ASpO2 and BIS:There were no significant difference of the SpO2and BIS value at T, in the four groups ( p >0. 05). There were significant difference of SBP, DBP and HR at T, in group I and group II. Compared with Tj, the SBP and DBP, the heart rate at T3_gin the four groups had significant decreased(p <0. 05). There was no significant difference of SBP, DBP, HR, RF and BIS value in the same age group. Compared with preoperation values, there were no significant difference of SBP, DBP, HR, RF and BIS value in the end of operation(p > 0. 05 ). Compared with Group I PK and IIPK, the re-spiratory rate and BIS value at T2₉in Group I PR and Group IIPR both decreased (p <0. 05). The SpO2of four groups decreased at T2₃, there was significant statistical difference compared with values before the operation (p <0.05). But there was no significant statistical difference between the groups.3. The adverse effect during and after the operation: one case in Group I PKand 3 cases in Group IIPK occurred respiratory inhibition. After adjusting the infusion rate of remifentanil and the mask assistant respiration for 1 min, the respiration inhibition disappeared. 4 cases in Group IIPR, occurred respiratory inhibition (RFs=8 times/min in two cases, glossocoma in two cases) , one case occurred in Group IPR( glossocoma) , there was no significant statistical difference in the four groups (p >0.05). Compared with Group I PKand Group IIPK, there was less body movement and restless in Group I PRand Group IIPR(p <0. 05). Compared with Group I PR, the restless after the operation decreased in Group IIPR, but there was no significant difference( p > 0.05) , and there was no statistical difference of the body movement in the operation (p >0. 05) . There was no significant difference of the oculocardiac reflex, nausea and vomiting and nightmare in four groups.4. The average infusion rate of propofol and remifentanil: There was no significant statistical difference of the average infusion rate of propofol in the four groups (p > 0. 05). The infusion rate of remifentanil in Group IIPR was lower than that in Group I PR( p <0. 05).5. The blood - gas analysis: the blood - gas analysis was done after the operation. There were no statistical difference of pH, PaO2, PaCO2 and BE value (p>0.05).6. Anesthesia induction, analepsia, consciousness recovery and total sedative time: Compared with Group I PK and Group IIPK, the induction time significantly prolonged in Group I PRand Group HPR(p <0.05). The induction time in Group I PR was significantly longer than that in Group IIPR ( p < 0.05 ) . Compared with Group I PK and IIPK, the interval of recovery time, analepsia time was significantly shorter in Group I PR and IIPR ( p < 0. 05). There was no significant difference of recovery time between Group I PR and Group IIPR, while the recovery time in Group IIPR significantly decreased (p <0. 05) ,and total sedative timewas shorter than Group I PK ( p < 0. 05 ) .7. The correlation between the BIS value and the average infusion rate of remifentanil and systolic blood pressure;The infusion rate of remifentanil in Group I PR and Group I1PR had negative correlation with BIS value x}= -0. 841, rn = -0. 826. The changes of SP in Group I PR and Group IIPRhad positive correlation with BIS value, i^ =0. 939,rn =0. 928.ConclusionIn the short - term pediatric ophthalmological operation in children, the combination usage of propofol and remifentanil using the BIS index direction may maintain the spontaneous respiration and meet the requirement of the operation and have the advantages of quick anesthesia recovery and less side effects. The pediatric usage of remifentanil had significant individual difference. In our study the average infusion rate of remifentanil for the younger children and the elder children were 0.151 0.027|xg. kg"1, min"1 and 0.134 ±0.022jxg. kg"1. min"1.