Objective To evaluate the accuracy of bispectral index (BIS) for monitoring the depth of sevoflurane anesthesia in children of different ages.Methods One hundred and five children (0-14 yr) undergoing abdominal surgery were divided into 3 age groups (n=35 each): group Ⅰ 4-14 yr (older children); group Ⅱ 1-3 yr (young children) and group Ⅲ < 1 yr (infants). All of the patients were anesthetized with sevoflurane combined with epidural or caudal blockade. Anesthesia was induced with 5 % sevoflurane in O_2. After tracheal intubation, the patients were mechanically ventilated. P_(ET) CO_2 was maintained at 35-45 mm Hg. The end-tidal sevoflurane concentration (C_(ET)Sev) Was maintained at 3.2%, 2.6%, 1.9% and 1.4% in infants < 6 months andat 2.5%, 2.0%, 1.5% and 1.0% in children > 6 months. Each C_(ET)Sev was maintained for at least 15 min. MAP, HR, P_(ET)CO_2 and BIS were monitored and recorded before anesthesia (T_1, baseline), at loss of consciousness (T_2), immediately after tracheal intuhation (T_3), at the 4 C_(ET)Sev (T_(4-7)), recovery of pharyngeal reflex (T_8), extubation (T_9) and emergence of anesthesia (T_10). Results BIS values were significantly higher in children of 1-3 yr (group Ⅱ) than in children of 3-14 yr (group Ⅰ) at T_(4,6,7). BIS values were significantly lower in infants (group Ⅲ) than in children of 3-14 yr (group Ⅰ) at T_(5-9). BIS values were significantly lower in infants (group Ⅲ) than in children of 1-3 yr (groupⅡ) at T_(3-10). There was significant negative correlation between BIS and C_(ET)Sev in all 3groups(γ=-0.768,-0.709,-0.357).Conclusion BIS can accurately reflect the depth of sevoflurane anesthesia in children (> 1 yr). BIS should be interpreted cautiously in infants (< 1 yr).

Objective To evaluate the accuracy of BIS value for monitoring the depth of sevoflurane-nitrous oxide in children. Methods Seventy-two ASA Ⅰ or Ⅱ children aged 1-14 yr undergoing abdominal surgery were randomly assigned into 3 groups ( n = 24 each) :sevoflurane group (group S), sevoflurane + 30% N2O group (group SN1 )and sevoflurane + 60% N2O (group SN2 ). Anesthesia was induced with atropine, lidocaine, propofol, rocuronium and remifentanil. After tracheal intubation, the patients were mechanically ventilated. PETCO2 was maintained at 35-45 mm Hg. Anesthesia was maintained with 2.5% sevoflurane combined with 0, 30% and 60% nitrous oxide in group S, SN1 and SN2 respectively. The end-tidal sevoflurane concentration (CETSev) was maintained at 2.5%, 2.0% and 1.5%. Each CETSev was maintained for at least 10 min after the begining of the surgery. Then the CETSev was modified to maintain BIS value at 40-60. BIS value was recorded before anesthesia induction and each stable CETSev. CETSev was recorded at maintaining BIS value of 40-60 for at least 20 min ( C50 ).Results BIS value and C50 were significantly lower in group SN2 than in group S and SN1 ( P ＜ 0.05), while no significant difference was found between group S and SN1 ( P ＞ 0.05). BIS value was negatively correlated with CETSev in all 3 groups (r = -0.736, -0.817, -0.729, P ＜ 0.01).There was no significant difference in the correlation coefficients among the 3 groups ( P ＞ 0.05 ). Conclusion BIS value can accurately reflect the depth of sevoflurane-nitrous oxide anesthesia in children.

ObjectiveTo compare the efficacy of intravenous infusion of dexmedetomidine and midazolam for premedication in children.MethodsNinety-two ASA Ⅰ or Ⅱ children (46 cases aged 1-3 yr and 46 cases aged 4-6 yr) scheduled for elective general or urologic surgeries,were enrolled in this study.The children were randomly divided into 2 groups (n =46 each):midazolam group (group M) and dexmedetomidine group (group D).The children accompanied by their parents were admitted to the anesthesia preparation room at about 20 min before induction of anesthesia,and midazolam 0.1 mg/kg òr dexmedetomidine 1 μg/kg was infused intravenously over 10 min.Anesthesia was induced with proporol-rocuroniume-remifentanil,and maintained with sevoflurane-remifentanil-rocuroniume.Modified Yale Preoperative Anxiety Scale (mYPAS) score,sedation score,HR,mean arterial pressure (MAP),respiratory rate (RR) and SpO2 were recorded before premedication (T1),before separation from their parents (T2) and when entering the operating room (T3).The incidence of sleep (a sedation score of 4) was recorded at T2,3.The end-tidal concentration of sevoflurane,infusion rate of remifentanil,laryngeal air way removal time,emergence time,duration of stay at the recovery room,incidence of delirium during recovery period,the percentage of patients requiring rescue analgesic,and adverse effects were also retorded.ResultsCompared to that at T1,the mYPAS score was significantly decreased at T2,3,and the sedation score was significantly increased at T2,3 in both groups ( P ＜ 0.05),HR at T2 and MAP at T2,3 were significantly decreased in group D,and HR at T3 was significantly increased in group M ( P ＜ 0.05 ).Compared to group M,the sedation scores and the incidence of sleep were significantly increased at T2,3,and the HR was significantly decreased at T2 in group D ( P ＜ 0.05).There was no significant difference in the mYPAS score,RR,MAP,SpO2,end-tidal concentration of sevoflurane,infusion rate of remifentanil,laryngeal air way removal time,emergence time,duration of stay at the recovery room,incidence of delirium during recovery period,the percentage of patients requiting rescue analgesic,and incidence of adverse effects between D and M groups ( P ＞ 0.05).ConclusionThe sedative efficacy of iv dexmedetomidine is superior to that of iv midazolam when infused for premedication in children,but it exerts much influence on hemodynamics,and the changes in hemodynamics should be noted.

Objective To compare the efficacy of closed-loop infusion of propofol for surgery in pe-diatric patients of different ages. Methods Forty-five pediatric patients of both sexes, weighing 10-63 kg, of American Society of Anesthesiologists physical statusⅠ or Ⅱ, scheduled for elective urologic sur-gery under general anesthesia, were divided into 3 groups(n=15 each)according to the age: infant group (1-3 yr), pre-school group(4-6 yr)and school-age group(7-12 yr). The bispectral index(BIS)moni-tor was connected to the closed-loop anesthesia delivery system, and the system automatically regulated the target plasma concentration of propofol to achieve a target BIS value of 45-55 during maintenance of anes-thesia. Remifentanil was given by target-controlled infusion at a target plasma concentration and rocuronium was intravenously injected when necessary during surgery. BIS40-60time percentage(percentage of time of BIS value maintaining at 40-60 in time of closed-loop infusion), median performance error(MDPE), me-dian absolute performance error(MDAPE), wobble and global score were recorded. The consumption of propofol, mean target plasma concentration and regulating frequency and consumption of remifentanil and rocuronium were recorded during surgery. Extubation time or laryngeal mask airway removal time, time to eye-opening and time of regaining consciousness were recorded. Results The BIS40-60time percentage was significantly higher, MDPE, MDAPE, wobble and global score were lower in pre-school and school-age groups than in infant group(P<005). Compared with pre-school group, the consumption of remifentanil was significantly decreased(P<005), and no significant change was found in BIS40-60time percentage, MDPE, MDAPE, wobble or global score in school-age group(P>005). There was no significant differ-ence in the consumption of propofol, mean target plasma concentration, regulating frequency, consumption of rocuronium, extubation time or laryngeal mask airway removal time, time to eye-opening or time of regai-ning consciousness among the 3 groups(P>005). Conclusion Closed-loop infusion of propofol produces better stability for surgery in pre-school and school-age children than in infants.

Objective? To use near-infrared spectroscopy (NIRS) to monitor the effects of peripheral artery catheterization on limb muscle oxygen saturation (SmO2) in infants and children. Methods? Totally 60 children aged under 36 months receiving selective operation in Children's Hospital, Capital Institute of Pediatrics between March and September 2017 were selected. NIRS was used to monitor and record the SmO2 of muscle of thenar or gastrocnemius muscle on the limbs of both sides before and after trachea cannula and artery cannulation under general anesthesia. The original SmO2 values of the limbs with or without cannulation were taken as controls to observe the changes of SmO2 of the limbs with cannulation after cannulation. Results? There was no statistically significant difference in original SmO2 values of the limbs with or without cannulation before cannulation (P＞0.05). The SmO2 values of the limbs with cannulation dropped after cannulation, which were lower than the values of the limbs without cannulation (P＜0.001). The decreasing range of SmO2 values of the children aged under 6 months were larger than those of the children aged between 6 and 12 months and between 12 and 36 months; and the decreasing range of SmO2 values of the children weighing under 10 kg were larger than those of the children weighing between 10 and 20 kg (P＜ 0.001). Conclusions? NIRS can accurately reflect the changes of SmO2 after artery cannulation in real time. NIRS used in monitoring helps to assess limb perfusion more precisely. Monitoring should be enhanced for limb perfusion in children aged under 6 months and weighing under 10 kg.

Objective:To analyze the effects of different mask ventilation modes on hemodynamics and gastric air intake in children with tonsillectomy and adenoid resection under general anesthesia.Methods:Eight-six children with tonsillectomy from January 2020 to December 2022 treatment in the Children′s Hospital Affiliated to Capital Institute of Pediatrics were enrolled and they were divided into the control group and the test group by random numbers table, 43 cases in each group. When inducing mask ventilation under general anesthesia, the control group used manual control ventilation mode, while the experimental group used pressure control volume assurance ventilation mode. The hemodynamics, respiratory parameters, antral area, and gastric air intake in the two groups at before mask ventilation (T 0), 60 s (T 1), 120 s (T 2), 180 s (T 3), and at the end of surgery (T 4) were compared between the two groups. Results:Compared with T 0, the heart rate (HR) and mean arterial pressure (MAP) of the two groups at T 1 and T 4 were reduced, but there were no statistical differences between the groups ( P>0.05). At T 1, T 2, and T 3, the peak airway pressure and average airway pressure in the experimental group were lower than those in the control group, T 1: (11.09 ± 2.36) cmH 2O (1 cmH 2O = 0.098 kPa) vs. (13.42 ± 2.15) cmH 2O, (4.98 ± 1.26) cmH 2O vs. (6.52 ± 1.73) cmH 2O; T 2: (11.32 ± 2.04) cmH 2O vs. (13.16 ± 2.37) cmH 2O, (5.11 ± 1.37) cmH 2O vs. (6.20 ± 1.55) cmH 2O; T 3: (11.25 ± 2.17) cmH 2O vs. (13.08 ± 2.29) cmH 2O, (4.93 ± 1.29) cmH 2O vs. (6.17 ± 1.48) cmH 2O, there were statistical differences ( P<0.05). After face mask ventilation, the area of the gastric antrum in the test group was smaller than that in the control group, and the incidence of gastric intake was lower than that in the control group: (2.17 ± 0.63) cm 2 vs. (2.51 ± 0.85) cm 2, 9.30% (4/43) vs. 34.88% (15/43), there were statistical differences ( P<0.05). Conclusions:Tonsillectomy and adenoid resection under general anesthesia in children, the use of pressure control volume to ensure ventilation mode during mask ventilation induced by anesthesia can maintain low respiratory parameters and reduce the incidence of gastric intake.