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Objective To compare the baroreflex sensitivity (BRS) when controlled hypotension was performed with sevoflurane versus isoflurane in the pediatric patients.Methods Sixty male American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients,aged 3-16 yr,with body mass index of 20-28 kg/m2,scheduled for elective scoliosis surgery under general anesthesia,were randomly divided into 2 groups (n=30 each) using a random number table:sevoflurane-induced hypotension group (group Sev) and isoflurane-induced hypotension group (group Iso).Anesthesia was induced with midazolam,sufentanil and propofol.Endotracheal intubation was facilitated with rocuronium.Anesthesia was maintained with closed-circuit low flow anesthesia with either sevoflurane or isoflurane,maintaining mean arterial pressure at 55-65 mmHg and bispectral index values at 40-60 during surgery.Cardiovascular BRS was measured before induction of anesthesia (T0),immediately after intubation (T1),immediately after the end-tidal inhalational anesthetic concentration reached 1 minimal alveolar concentration (T2),and at 10,20 and 30 min after target hypotension (mean arterial pressure 55-65 mmHg) was achieved (T3-5).Results There was no significant difference in BRS at T0-2 between the two groups (P＞0.05).Compared with the value at To,the BRS was significantly decreased at the other time points in the two groups (P＜0.05).Compared with the value at T1,the BRS was significantly increased at T2,and decreased at T3-5 in the two groups (P＜0.05).The BRS was significantly lower at T3-5 than at T2 in the two groups (P＜0.05).The BRS was significantly lower at T3-5 in group Sev than in group Iso in the two groups (P＜0.05).Conclusion Sevoflurane produces better efficacy than isoflurane when used for controlled hypotension in the pediatric patients.
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Objective To determine the dose-response relationship of 0.2％ ropivacaine for ultrasoundguided stellate ganglion block (SGB).Methods Seventy-five ASA physical status [or Ⅱ patients with migraine,aged 23-55 yr,with body mass index of 22-28 kg/m2,scheduled for elective ultrasound-guided SGB,were randomly divided into R1-5 groups (n =15 each) using a random number table.In R1,R2,R3,R4 and R5 groups,the patients underwent ultrasound-guided SGB with 0.2％ ropivacaine 1,2,3,4 and 5 ml,respectively.A successful SGB block was confirmed by the onset of ptosis (Horner syndrome) on the injected side.Probit analysis was used to calculate the effective dose of 0.2 ％ ropivacaine in 50 ％ and 95 ％ of the patients (ED50 and ED95) and 95％ confidence interval (95％ CI).Results The ED50 of 0.2％ ropivacaine for ultrasound-guided SGB was 2.2 ml (95％CI 1.9-2.5 ml) and ED95 was 3.2 ml (95％CI 2.8-4.1 ml).Conclusion The ED50 and ED95 of 0.2％ ropivacaine for ultrasound-guided SGB are 2.2 and 3.2 ml,respectively.
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Objective To compare dexmedetomidine versus lidocaine for suppression of fentanyl-induced coughing during induction of general anesthesia in patients.Methods Two hundred ASA physical status Ⅰ or Ⅱ patients,aged 36-50 yr,undergoing elective gynecological operations under total intravenous anesthesia,were randomized into 2 groups (n =100 each):dexmedetomidine group (group D) and lidocaine group (group L).Dexmedetomidine 0.5 μg/kg was intravenously infused over 10 min at a rate of 0.05 μg· kg-1· min-1 starting from 20 min before induction of anesthesia in group D.Lidocaine 0.5 mg/kg was injected intravenously at 1 min before induction of anesthesia in group L.For induction of anesthesia,fentanyl was given first,and 2 min later the other drugs were given.The development and degree of coughing were recorded within 1 min after fentanyl injection.The occurrence of adverse events was recorded.Results The incidence of coughing was significantly higher and the degree of coughing was severer in group L than in group D (P ＜ 0.05).There was no signihicant difference in the incidences of hypotension and severe sinus bradycardia between groups D and L (P ＞ 0.05).Conclusion Dexmedetomidine 0.5 μg/kg injected before induction of anesthesia has better suppressive effect on fentanyl-induced coughing during induction of general anesthesia than lidocaine 0.5 mg/kg in patients.