Effect Of Neuromuscular Blockade Of Mivacurium In Removing Bronchial Foreign Body In Children

Objectives:The aim of this study was to investigate the effect of different doses of mivacurium in removimg bronchial foreign body in children of different age groups,which can provide a scientific basis for rational drug use in clinical practice in bronchial foreign bodies in children.Methods:100 children American Society of Anesthesiologists（ASA）gradeⅠorⅡ,aged 1-5 years,undergoing removing bronchial foreign body were enrolled from January 2017 to December 2017 in Children’s Hospital of HeBei Province,normal development,no cardiovascular disease,and the history of foreign bodies were not more than 1 month.All the children were randomly divided into four groups according to their age and the initial dosage of mivacurium（n=25）,respectively,group Ia（child group,1-3 years old）:Intravenous injection of mivacurium 0.15 mg/kg when induction of anesthesia;Ib（child group,1-3 years old）:Intravenous injection of mivacurium0.20 mg/kg when induction of anesthesia;IIa（older child group,3-5 years old）:Intravenous injection of mivacurium 0.15 mg/kg when induction of anesthesia;IIb（older child group,3-5 years old）:Intravenous injection of mivacurium 0.20 mg/kg when induction of anesthesia.The electrocardiogram（ECG）,noninvasive blood pressure（NIBP）,and blood oxygen saturation were monitored as soon as the children were took into the operating room,and the muscular relaxation monitor was also connected.After opening the venous channel,penehyclidine 0.02 mg/kg,0.3⁰.5mg/kg dexamethasone were injected by intravenous infusions and propofol 1-2mg/kg,fentanyl 1-3μg/kg were also injected for the induction of anesthesia.When the patients were unconsciousness,the injection system of CLMRIS-1closed loop muscle relaxant was opened.group Ia and group IIa were intravenously injected with 0.15 mg/kg mivacurium at the induction of anesthesia,and intravenous doses of 0.2 mg/kg mivacurium were given in s group Ib and group IIb were intravenously injected with 0.2 mg/kg mivacurium at the induction of anesthesia,injection time is 30s.Subsequently,the patients were inserted into high frequency jet ventilation at a frequency of80/min through the side port of bronchoscopy using the high-frequency jet ventilator after removing body successfully.We observed the breathing of the children carefully.The rates of spontaneous respiration and the tidal volume were steady,and then the bronchoscopy was taken out completely.The muscle relaxation time index was observed and recorded which including the onset time,clinical duration（the interval from the injection of the muscle to the Th recovery of 25%）,recovery index（RI）（the Th recovery of 25%to 75%）and the recovery time of TOF TOFr（T₄/T₁）,the fourth Th（returned to 75%）to the first Th（returned to 90%）ratio（TOFr 75,TOFr 90）.MAP、HR、and blood oxygen saturation were observed and recorded at the time of pre-anesthesia（T₁）,pre-inserting the bronchoscopy（T₂）,1 min after inserting the bronchoscopy（T₃）,3 min after inserting the bronchoscopy（T₄）and taking out the bronchoscopy（T₅）.The mirror satisfaction rates and the operation time also were recorded.We observed the incidence rates of the skin flushing,low blood pressure and bronchospasm in children.Results:There was no significant difference in age,height,weight and operation time in group I（1-3 years old）and II（3-5 years old）（P>0.05）.Onset time of the different doses:Compared with group I a,there was a significantly shortened in groupⅠb in ThDmax（P<0.05）;Compared with groupⅡa,there was a significantly shortened in groupⅡb in ThDmax（P<0.05）.Onset time of different age:Comparison with groupⅠa,the ThDmax was obviously prolonged in groupⅡa（P<0.05）;Compared with groupⅠb,the ThDmax was obviously prolonged in groupⅡb（P<0.05）.There were no difference in the time of clinical action,recovery index（RI）,TOFr（T4/T1）and TOF ratio（TOFr）recovery to 0.75 and 0.9（P>0.05）.There was no significant difference in MAP,HR and blood oxygen saturation before and after bronchoscope after injection of mivacurium chloride（P>0.05）.In group Ia,group Ib,group IIa and group IIb,the satisfaction rate of inserting mirror was 96%,100%,88%and 96%respectively and there were no significant difference among the groups（P>0.05）.The incidences of skin flushing in anterior neck and colpus in groupⅠa,Ⅰb,Ⅱa,andⅡb were 8%、8%、12%and 4%respectively,and the incidence rate was no significant difference（P>0.05）.Low blood pressure and bronchospasm were not observed in both groups.Conclusion:It was found that the onset time for children was obviously shorter than that for the elder ones when the same doses of mivacurium were used during the anesthesia induction.While,there were not differences between the two groups of children on the muscle relaxation effect;0.15mg/kg mivacurium can offer a satisfactory muscular relaxant effect for the children undergoing removing bronchial foreign body.