Objective:To evaluate the effect of different clear fluid fasting duration on the fluid responsiveness after anesthesia induction in pediatric patients with congenital heart disease.Methods:One hundred pediatric patients with congenital heart disease who underwent elective atrial septal defect or ventricular septal defect correction surgery at Shanghai Children′s Medical Center affiliated to Shanghai Jiao Tong University School of Medicine from December 2023 to February 2024 were selected. They were of either sex, aged 6 months to 3 yr, with a body mass index of 13-19 kg/m 2, and classified as American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ. Patients who adhered to the prescribed preoperative clear fluid fasting regimen, with a fasting duration of 6 h or longer before surgery, were included in the long fasting (LF) group, while those who were prescribed multi-dimensional nutritional solution until 2 h before surgery with a solid fasting duration≥6 h were considered for inclusion in the short fasting (SF) group. The diastolic blood pressure (DBP) was recorded immediately before and after liver compression test at pre-induction of anesthesia and immediately before and after liver compression test at post-induction of anesthesia, and the changes in DBP before and after the liver compression test (ΔDBP) were calculated. Positive fluid responsiveness was defined as an increase in ΔDBP ≥ 6.25%. The positive rate of fluid responsiveness before and after anesthesia induction was calculated. Results:Sixty-four patients were finally included, and both LF and SF groups included 32 cases. Before the induction of anesthesia, the positive rate of fluid responsiveness induced by liver compression was 28.1% in LF group and 18.8% in SF group, and the difference was not statistically significant ( P>0.05). However, after the induction of anesthesia, the positive rate of fluid responsiveness induced by liver compression was 56.3% in LF group and 28.0% in SF group, with a statistically significant difference observed ( P<0.05). Compared with the baseline before anesthesia induction, the positive rate of fluid responsiveness was significantly increased in LF group( P<0.05), and no significant change was found in the positive rate of fluid responsiveness in SF group ( P>0.05). Conclusions:The prolonged clear fluid fasting may lead to an increase in the positive rate of fluid responsiveness following anesthesia induction in pediatric patients with congenital heart disease, presenting as a state of hypovolemia.

Objective To investigate risk factors of postoperative pulmonary complications(PPCs)in children after video-assisted thoracoscopic lung resection.Methods Retrospective analysis of clinical data of 566 children,334 males and 232 females,aged≤6 years,ASA physical statusⅠorⅡ,enrolled for video-assisted thoracoscopic lung resection.The children were divided into two groups based on whether they developed PPCs within 7 days after surgery:the PPCs group and the non-PPCs group.Factors with P≤0.2 and perceived as potentially clinically meaningful,were included in the binary logistic regression model.The receiver operating characteristic(ROC)curve was drawn and the area under the curve(AUC)was calculated.Results A total of 123 children(21.7%)developed postoperative pulmonary compli-cations(PPCs).Multivariate logistic regression analysis showed longer duration of one-lung ventilation(OLV),faster respiratory rate during OLV and inexperienced surgeon were found to be independently risk factors of PPCs.Higher PEEP level was protective factors of PPCs(The maximum PEEP was 7 cmH2 O).The prediction model was Logit(P)=-4.41+0.006×OLV duration+0.063×OLV respiratory rate+0.569×inexperienced surgeon(yes = 1)-0.16×maximum PEEP value.The ROC curve showed a good accuracy with an area under the curve of 0.682(95%CI 0.631-0.734),and sensitivity was76.4%,and specificity was 69.6%.Conclusion Longer OLV duration,faster repiratory rate and less surgeon experience are found to be independently risk factors of PPCs.Higher PEEP level is protective factor of PPCs.

Objective To calculate median effective dose(ED50)of remimazolam combined with sufentanil for inhibition of nasopharyngeal airway insertion reaction in elderly patients.Methods Thirty-eight patients,aged≥65 years,BMI 18-25 kg/m2,ASA physical statusⅠ-Ⅲ,undergoing elective cata-ract surgery under nasopharyngeal airway were selected.Patients received intravenous sufentanil injections of 0.1 μg/kg,followed by intravenous remimazolam injection 3 minutes later,then nasopharyngeal airway in-sertion after 2 minutes.The initial dose of remimazolam was 0.2 mg/kg and adjusted by 0.01 mg/kg,based on the modified Dixon sequential method.A positive reaction was defined as head shaking,choking,body movement,an increase in HR＞20%of the basal value,or an increase in SBP or DBP＞20%of the basal value at the time of nasopharyngeal airway placement.The procedure was stopped after seven crossovers.The ED50,95%effective dose(ED95)of remimazolam,and 95%confidence intervals(CI)were calculated by probabilistic unit(Probit)regression analysis.Results When combined with sufentanil,the ED50 and ED95 of remimazolam for inhibition of nasopharyngeal airway insertion in elderly patients was 0.193 mg/kg(95%CI 0.191-0.195 mg/kg)and 0.209 mg/kg(95%CI 0.205-0.213 mg/kg),respectively.Conclusion The ED50 of remimazolam combined with sufentanil for inhibition of nasopharyngeal airway in-sertion reaction in elderly patients were 0.193 mg/kg(95%CI 0.191-0.195 mg/kg).

Objective To investigate if anesthetic sensitivity to propofol will be restored after biliary decompression.Methods Twenty-four adult male SD rats were randomly assigned into 3 groups:sham group (group S),irreversible obstructive jaundice group (group Ⅰ) and reversible obstructive jaundice group (group R).The serum total bilirubin (TBL) and total bile acid (TBA) concentratins were detected in the rat blood samples collected from the caudal vein before and after the operation,3,7,14,21 d respectively.Propofol was administered to measure the time of loss of righting reflex and recovery pre or 7th and 21th day post ligation.Results Serum TBL and TBA in group Ⅰ and serum TBA in group R were significantly higher than that in group S on 3rd,7th,14th,21th day post surgery(P＜0.05).Compared with group S,seum TBL in group R were significantly high on 3rd,7th,14th day post-surgery.Serm TBL and TBA in group R were significantly lower than group Ⅰ on 14th,21th day post-surgery (P＜0.05).Compared with group S,the time to loss of righting reflex in group I and group R were significantly shortened and the time to recovery were significantly increased on 7th day post-surgery (P＜0.05).Conclusion Obstructive jaundice could significantly potentiate the ability of propofol to induce a loss of righting reflex,and the increased anesthesia sensitivity will be restored after biliary decompression.

Objective To evaluate the efficacy and safety of chloral hydrate combined with dexmedetomidine for sedation during echocardiography in pediatric patients with Williams-Beuren syndrome.Methods Eighteen pediatric patients diagnosed with Williams-Beuren syndrome by genetic testing,aged 5-58 months,scheduled for elective echocardiography under sedation,received oral chloral hydrate 50 mg/kg.Vital signs were measured every 5 min,and sedation was assessed using Ramsay sedation score.When Ramsay sedation score＜4 points 20 min later,intranasal dexmedetomidine 1 μg/kg was given as rescue sedative.Medicine used,vital signs,onset time,moderate and deep sedation duration and emergence time were recorded.Results The success rate of sedation with chloral hydrate alone was 38.9％ and with chloral hydrate and dexmedetomidine 61.1％.The onset time,sedation duration and emergence time were (15.7+1.9) min,(75+26) min and (52+25) min,respectively,in pediatric patients received chloral hydrate alone.The onset time,sedation duration and emergence time were (33.2±3.4) min,(83±49) min and (61±46) min,respectively,in pediatric patients received chloral hydrate and dexmedetomidine.The onset time was significantly prolonged in pediatric patients received chloral hydrate and dexmedetomidine than in pediatric patients received chloral hydrate alone (P＜0.05).Heart rate,respiratory rate and SpO2 were stable during sedation in all pediatric patients,and nausea and mild vomiting were found in 3 pediatric patients received chloral hydrate and in 6 pediatric patients received chloral hydrate and dexmedetomidine,and no other adverse reactions were observed.Conclusion Oral chloral hydrate 50 mg/kg combined with intranasal dexmedetomidine 1 μg/kg provides reliable sedative efficacy and exerts less influence on respiratory and circulatory function with higher safety when used for echocardiography in pediatric patients with Williams-Beuren syndrome.

Objective To evaluate the effect of age factor on the analgesic efficacy of morphine during recovery from remifentanil-based anesthesia in pediatric patients undergoing minor surgery.Methods Fifty pediatric patients of both sexes,aged 3-10 yr,with body mass index ≤ 30 kg/m2,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,scheduled for elective tonsillectomy,were divided into preschool group (3-5 yr,n=30) and school-age group (6-10 yr,n =20) according to age.Anesthesia was induced by inhaling 8％ sevoflurane and Ⅳ morphine 0.1 mg/kg.Pediatric patients were mechanically ventilated after tracheal intubation,and end-tidal pressure of carbon dioxide was maintained between 35-45 mmHg.Anesthesia was maintained by inhalation of 2％-3％ sevoflurane and Ⅳ infusion of remifentanil 0.2 μg · kg-1 · man-1.Pain was evaluated using Faces Pain Scale (FPS) and Face Legs Activity Cry Consolability (FLACC) scale during the recovery period in the postanesthesia care unit.When FPS or FLACC scores ≥ 4.morphine 0.05 mg/kg was intravenously injected.When pain was still unrelieved after morphine was given for 2 times (time interval 5 min),fentanyl 1 μg/kg was intravenously injected until FPS and FLACC scores ＜4.The requirement for analgesics and consumption of analgesics (fentanyl consunption was converted into morphine consumption) were recorded.The development of nausea and vomiting,pruritus and respiratory depression was also recorded.Results Compared with preschool group,the requirement for analgesics and consunption of analgesics were significantly decreased during recovery from anesthesia (P＜0.05),and no significant change was found in the incidence of nausea and vomiting in school-age group (P＞0.05).No pruritus or respiratory depression was found in two groups.Conclusion The analgesic efficacy of morphine is affected by age factors during recovery from remifentanil-based anesthesia in pediatric patients undergoing minor surgery,and morphine produces better analgesic efficacy in school-age pediatric patients than in preschool pediatric patients.

Objective To evaluate the accuracy of ultrasonographic measurement of the subglottic airway diameter in selecting the cuffed endotracheal tube (ETT) size for the pediatric patients with congenital heart disease.Methods Sixty pediatric patients of both sexes with congenital heart disease,of American Society of Anesthesiologists physical status Ⅱ-Ⅳ,aged 1 month-7 yr,undergoing elective open heart surgery,were included in this study.The subglottic airway diameter was measured by bedside ultrasonography after induction of anesthesia.The outer diameter of the cuffed ETT was determined according to the subglottic airway diameter.The air leak test was performed after intubation to determine whether or not the ETT size selected based on ultrasonography was appropriate.When the difference between the inner diameter of the finally selected ETT and the result calculated by the Motoyama formula was less than 0.2 mm,the ETT size selected based on the Motoyama formula was considered appropriate.The agreement and correlation between the subglottic airway diameter measured by age-based formula and ultrasonography and the outer diameter of the actually selected ETT were analyzed using Bland-Altman plot and Passing-Bablok regression analysis.Results The accurate rate of the ETT selected based on the ultrasonic measurement and Motoyama formula were 80％ and 55％,respectively,and there was significant difference (P＜0.05).Conclusion Ultrasonographic measurement of the subglottic airway diameter produces higher accuracy than the classical Motoyama formula in selecting the cuffed ETT size for the pediatric patients with congenital heart disease.

Objective To investigate the effect of preoperative oral midazolam on emergence agitation after sevoflurane anesthesia in children.Methods Sixty children,34 males,26 females, aged 2-7 years,ASA grade Ⅰ or Ⅱ,receiving sevoflurane for tonsillectomy/adenoidectomy were ran-domly divided into low dose midazolam group (group M1),high dose midazolam group (group M2) and control group (group C)(n=20 each).The 5 ml mixture of midazolam 0.5 mg/kg,0.75 mg/kg and 10% glucose was taken orally 30 min before anesthesia in group M1 and group M2,respectively. While 5 ml of 10% glucose was given in group C.Anesthesia was induced with inhalation of 8%sevoflurane and maintained with intravenous infusion of remifentanil and inhalation of sevoflurane. Scores of parental separation anxiety scale(PSAS),pediatric anesthesia emergence delirium scale (PAED scale),FLACC scale were compared.Times to extubation and discharge from PACU were al-so recorded.Results Group C showed significantly higher incidence of separation anxiety(P <0.05). The incidence of emergence agitation,peak PAED scores,FLACC scores,time to extubation were similar among three groups.Discharge time from PACU was longer in group M2 (P < 0.05). Conclusion Preoperative oral midazolam 0.5 mg/kg or 0.75 mg/kg can effectively reduce parental separation anxiety.This,however,dose not result in a reduced incidence of emergence agitation after sevoflurane anesthesia.Midazolam 0.75 mg/kg can extend the discharge time from PACU.

Objective To evaluate the pharmacodynamics of oral chloral hydrate sedation for echocardiography in pediatric patients with congenital heart disease (CHD).Methods Two hundred ASA physical status Ⅱ-Ⅳ pediatric patients with CHD, aged 5-620 days,scheduled for elective echocardiography,were enrolled in the study.The dose of oral chloral hydrate was set at 50 mg/kg in the first pediatric patient.The oral dosage was determined by up-and-down sequential experiment.Each time the oral dose increased/decreased by 10％ in the next pediatric patient.The pharmacodynamics was analyzed based on the dose-response model to determine the 50％ effective dose (ED50),95％ effective dose (ED95) and 95％ confidence interval (95％ CI) of chloral hydrate for sedation.The covariates (age,gender,time period of administration,fasting time,sleeping at 2 h before sedation,premature and cyanotic CHD) were introduced into the dose-response model,and the effect of each covariate on the pharmacodynamics of chloral hydrate sedation was evaluated.Results The ED50 of chloral hydrate for sedation during echocardiography was 42.2 mg/kg (95 ％ CI 40.2-44.2 mg/kg), ED95 was 67.4 mg/kg (95％ CI 53.7-81.1 mg/kg) in the pediatric patients with CHD.Each covariate provided no effect on the pharmacodynamics of chloral hydrate sedation (P ＞ 0.05).When fasting time and premature were introduced into the dose-response model,95％ CI of the slope of dose-response curve included 0.When age which was stratified was introduced into the dose-response model,it was difficult to fit or the data seriously deviated from the clinical data.Conclusion The ED50 and ED95 of chloral hydrate for sedation during echocardiography were 42.2 mg/kg (95％ CI 40.2-44.2 mg/kg) and 67.4 mg/kg (95％CI 53.7-81.1 mg/kg),respectively,in the pediatric patients with CHD.Gender,time period of administration,sleeping before sedation and cyanotic CHD do not affect the pharmacodynamics of oral chloral hydrate sedation,while the effect of age,fasting time and premature needs further determination.

Objective To establish the pharmacodynamic model of sevoflurane with bispectral index (BIS) as the effective index in pediatric patients.Methods Thirteen ASA physical status Ⅰ or Ⅱ pediatric patients,aged 4-9 yr,weighing 12-39 kg,undergoing non-cardiac surgery,were selected in the study.The pediatric patients sequentially inhaled 1％,5 ％ and 1％ sevoflurane via a face mask and each concentration was inhaled for 15 min.BIS value,HR,BP and SpO2 were automatically recorded every 10 s.Based on nonlinear mixed effect modeling,the population pharmacodynamic model of sevoflurane was established using NONMEM software.The effect of age on the pharmacodynamic parameters was evaluated using a stepwise forward addition then backward elimination modeling approach.The standard for model improvement was defined as a decrease in the value of the objective function by more than 3.84.Results Twelve pediatric patients,aged 4.0-8.5 yr,weighing 12.8-38.0 kg,with body height of 92-135 cm,were enrolled in this study and the data which were enrolled comprised 2964 effective concentration-time-BIS points.The model was not improved significantly with any covariates (age,body height,and body weight) introduced (P ＞ 0.05).The estimated parameters of the final pharmacodynamic model of sevoflurane were as follows:ke0 =O.516/min ; EC50 (BIS50) =2.11％ ; γ =2.46 ; E0 =74.6 ; EMAx =11.2.Conclusion The pharmacodynamic model of sevoflurane is successfully established with BIS as the effective index in pediatric patients,and the analysis for each parameter of the model indicates that the sensitivity to sevoflurane is lower,but the blood-brain equilibration time of the drug is shorter and the onset and recovery are faster in children than in adults.