| Part I A comparison of respiratory dynamics between LMA-I-gel and LMA-Ambu in children under six-year-old with general anesthesiaObjective:Some drawbacks of classic laryngeal mask airway, such as upper airway semi-obstruction, gastric distension or leakage, limited its application in children under 6 years of age. LMA-I-gelTM and LMA-Ambu Aura OnceTM are two types of LMA which is improved on the basis of traditional laryngeal mask to be suitalbe for pediatric anesthesia, while there is lack of detailed parameters of respiratory dynamics. The study was designed to compare the efficacies of the LMA-I-gel and the LMA-Ambu in children under six-year-old during general anesthesia by using continuous airway monitoring technique.Methods:Children,ASA I, aged one month to six-year-old, undergoing urologic surgical procedures were randomly divided into two groups by different age group. Group C was aged one month to twelve months.Group I was aged thirteen months to six-year-old.LMA-I-gel and LMA-Ambu were inserted as subgroup CA(n=35),CI(n=35),IA(n=15) and II(n=15), respectively. Children in group C were undergoing general anesthesia combined caudal block.Infants in group I were undergoing general anesthesia.Main outcome measures:Parameters for respiratory mechanics including tidal volume(VTin/ex), peak inspiratory pressure(PIP), plateau airway pressure(Pplat), positive end expiratory pressure(PEEP),peak expiratory flow(PEF) and end tidal CO2(ETCO2).The inspiratory/ expiratory tidal volume per kilogram body weight [VT(in/ex)/kg],leakage fraction(LF),expiratory resistance(Re), dynamic compliance( Cdyn) and static compliance(Cst)were calculated. Secondary outcome measures: inserting time, Achievement ratio of insertion, classification after bronchoscope of Fiber Optic Bronchoscope(FOB), airway leakage pressure(LP), BIS value during anesthesia, the hemodynamic data: mean arterial pressure(MAP), heart rate(HR) and pulse Oximetry saturation(Sp O2) and the complications after implantation or extraction were recorded. Hemodynamic data and BIS value were recorded after intravenous induction and 0, 10, 20, 30 min after intubation.Parameters for respiratory mechanics and LP were recorded 0, 10, 20, 30 min after intubation.Results:At each time point,the PEF in subgroup CA and IA were significantly higher than those in subgroup CI and II(P<0.05),the Re in subgroup CA and CI were significantly lower than those in subgroup IA and II(P<0.05).At the time point of 0 min after the insertion of LMA,the VT(in/ex) was significantly higher in subgroup CA and IA than those in subgroup CA and CI(P<0.05).The Cdyn and Cst in group IA were significantly higher than those in group II(P<0.05).Meanwhile,the Achievement ratio of insertion and FOB were no significantly difference in two groups(P>0.05).The inserting time was significantly shorter in groups I-gel than those in groups Ambu(P<0.05).The LP at each time point was significantly higher in groups I-gel than those in groups Ambu(P<0.05).There were no significant differences in the complications in both groups(P>0.05), except the incidence of gastrectasia was higher in groups Ambu(P<0.05). Other data was no significantly difference in all groups.Conclusion:Both LMA-I-gel and LMA-Ambu can be used for effective airway management in children under six-year-old during general anesthesia. Moreover, LMA-I-gel presents shorter insertion time, better airway sealing, less complications, which should be more convenient for the airway management in children.Part II A comparison of respiratory dynamics between caudal block and no caudal block combined with general anesthesia by laryngeal airway mask Ambu in children aged one-year-old to three-years-old.Objective:For children aged one-year-old to three-years-old undergoing abdominal and perineal surgery,Caudal block combined with general anesthesia has been widely used for the advantages of simple operation,safety,less injury,wide range of block and higher success rate. Meanwhile, the incidence of hypoxemia was higher in children undergoing general anesthesia in this age group. The study was designed to compare the efficacies of the caudal block and no caudal block combined with general anesthesia by laryngeal airway mask(LMA) Ambu in children aged one-year-old to three-years-old by using continuous airway monitoring technique.Methods: sixty pediatric patients, ASA I, aged 1 to 3 years, undergoing urologic surgical procedures were randomly divided into two groups. Caudal block combined with general anesthesia and general anesthesia were inserted in group C and G(n=30 in each), respectively.Main outcome measures:Parameters for respiratory mechanics including tidal volume(VTin/ex), peak inspiratory pressure(PIP), plateau airway pressure(Pplat), positive end expiratory pressure(PEEP),peak expiratory flow(PEF) and end tidal CO2(ETCO2).The inspiratory/ expiratory tidal volume per kilogram body weight [VT(in/ex)/kg],leakage fraction(LF),expiratory resistance(Re), dynamic compliance( Cdyn) and static compliance(Cst)were calculated. Secondary outcome measures: inserting time, Achievement ratio of insertion, classification after bronchoscope of Fiber Optic Bronchoscope(FOB), airway leakage pressure(LP), BIS value during anesthesia, the hemodynamic data: mean arterial pressure(MAP),heart rate(HR) and pulse Oximetry saturation(Sp O2) and the complications after implantation or extraction were recorded. Hemodynamic data and BIS value were recorded after intravenous induction and 0, 10, 20, 30 min after intubation.Parameters for respiratory mechanics and LP were recorded 0, 10, 20, 30 min after intubation.Results: At the time point of 10 min,20min and 30 min after the insertion of LMA,the Lf in group G was significantly higher than that in group C(P<0.05).Compared with each time point in each group,VT(in/ex),VT(in/ex) per kilogram body weight,Cdyn and Cst were higher in 0min than those in the other time points(P<0.05).In 30 min point, Pplat and Re in group C were higher than those in 0min point(P<0.05).PIP,Pplat and Re in group G were significantly higher in 30 min point than those in 0min and 10 min points(P<0.05).Meanwhile,compared with group C,the cuff pressure of LMA in group G was significant changes in time point of 10 min,20min and 30min(P<0.05). Other data was no significantly difference in all groups.Conclusion: The changes of parameters for respiratory mechanics are fairly smooth by caudal block combined with general anesthesia. After caudal blocked, children who used LMA in machine ventilate are non-essential to inhale N2 O.N2O will increase the cuff pressure of LMA which will lead to incease the incidence of leakage or gastrectasia.Generally speaking,it is safer for children aged one-year-old to three-years-old undergoing abdominal and perineal surgery by caudal block combined with general anesthesia. |
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