Determination of 50% effective concentration of ropivacaine plus sufentanil in dural puncture epidural analgesia for labor / 中国医师进修杂志

Objective:To determine the 50% effective concentration (EC 50) of ropivacaine plus sufentanil for labor analgesia using the dural puncture epidural technique. Methods:Using the method of prospective study, sixty parturients requiring labor analgesia in Dalian Women and Children′s Medical Group from May 2021 to May 2022 were divided into six groups using a random number table and administered 0.3 mg/L sufentanil and ropivacaine at different concentrations: 0.05% (group D1), 0.06% (group D2), 0.07% (group D3), 0.08% (group D4), 0.09% (group D5), and 0.1% (group D6). A probit model was constructed to compute the EC 50 values and 95% confidence intervals (95% CI) of ropivacaine plus sufentanil in dural puncture epidural analgesia (DPEA) for labor. The pain intensity of uterine contractions before labor analgesia and 30 min after administration was recorded and assessed on a numeric rating scale (NRS), and decreases in blood pressures and heart rates, vomiting and nausea, postpartum headaches, and fetal bradycardia were documented. Results:When using ropivacaine plus sufentanil for labor analgesia via DPE, the EC 50 was 0.061%, and the 95% CI ranged from 0.051 to 0.067; the 90% effective concentration (EC 90) was 0.081%, and the 95% CI was between 0.074 and 0.098. Among the six groups, there was one case of fetal bradycardia in group D3 and one case of decreased heart rates in group D4. No decreased blood pressure, vomiting and nausea, or postpartum headaches were reported. Conclusions:In DPEA for labor, ropivacaine plus sufentanil has an EC 50 of 0.061%, with the 95% CI falling between 0.051 and 0.067, similar to the EC 50 value in epidural analgesia.

Effect of pre-administered flurbiprofen axetil on the EC50 of propofol during anesthesia in unstimulated patients: a randomized clinical trial / Efeito da pré‐ administração de flurbiprofeno axetil na CE50 do propofol durante anestesia em pacientes não estimulados: estudo clínico randomizado

Abstract Background and objectives Preoperative use of flurbiprofen axetil (FA) is extensively adopted to modulate the effects of analgesia. However, the relationship between FA and sedation agents remains unclear. In this study, we aimed to investigate the effects of different doses of FA on the median Effective Concentration (EC50) of propofol. Methods Ninety-six patients (ASA I or II, aged 18-65 years) were randomly assigned into one of four groups in a 1:1:1:1 ratio. Group A (control group) received 10 mL of Intralipid, and groups B, C and D received 0.5 mg.kg−1, 0.75 mg.kg−1 and 1 mg.kg−1 of FA, respectively, 10 minutes before induction. The depth of anesthesia was measured by the Bispectral Index (BIS). The "up-and-down" method was used to calculate the EC50 of propofol. During the equilibration period, if BIS ≤ 50 (or BIS > 50), the next patient would receive a 0.5 µg.mL−1-lower (or -higher) propofol Target-Controlled Infusion (TCI) concentration. The hemodynamic data were recorded at baseline, 10 minutes after FA administration, after induction, after intubation and 15 minutes after intubation. Results The EC50 of propofol was lower in Group C (2.32 µg.mL−1, 95% Confidence Interval [95% CI] 1.85-2.75) and D (2.39 µg.mL−1, 95% CI 1.91-2.67) than in Group A (2.96 µg.mL−1, 95% CI 2.55-3.33) (p = 0.023, p = 0.048, respectively). There were no significant differences in the EC50 between Group B (2.53 µg.mL−1, 95% CI 2.33-2.71) and Group A (p > 0.05). There were no significant differences in Heart Rate (HR) among groups A, B and C. The HR was significantly lower in Group D than in Group A after intubation (66 ± 6 vs. 80 ± 10 bpm, p < 0.01) and 15 minutes after intubation (61 ± 4 vs. 70 ± 8 bpm, p < 0.01). There were no significant differences among the four groups in Mean Arterial Pressure (MAP) at any time point. The MAP of the four groups was significantly lower after induction, after intubation, and 15 minutes after intubation than at baseline (p < 0.05). Conclusion High-dose FA (0.75 mg.kg−1 or 1 mg.kg−1) reduces the EC50 of propofol, and 1 mg.kg−1 FA reduces the HR for adequate anesthesia in unstimulated patients. Although this result should be investigated in cases of surgical stimulation, we suggest that FA pre-administration may reduce the propofol requirement when the depth of anesthesia is measured by BIS.

Resumo Justificativa e objetivos A administração pré‐operatória de Flurbiprofeno Axetil (FA) é amplamente usada para a modulação da analgesia. No entanto, a relação entre FA e fármacos sedativos permanece obscura. Neste estudo, nosso objetivo foi investigar os efeitos de diferentes doses de FA na Concentração Efetiva mediana (CE50) do propofol. Métodos Noventa e seis pacientes (ASA I ou II, com idades de 18-65 anos) foram alocados aleatoriamente em quatro grupos na proporção de 1:1:1:1. Dez minutos antes da indução, o Grupo A (grupo controle) recebeu 10 mL de Intralipid, enquanto os grupos B, C e D receberam FA na dose de 0,5 mg.kg‐1; 0,75 mg.kg‐1 e 1 mg.kg‐1, respectivamente. A profundidade da anestesia foi medida pelo Índice Bispectral (BIS). O método up‐and‐down foi usado para calcular a CE50 do propofol. Durante o período de equilíbrio, se o valor do BIS fosse ≤ 50 ou BIS > 50, o próximo paciente tinha a infusão de propofol ajustada para uma concentração alvo‐controlada 0,5 µg.mL‐1 inferior ou superior, respectivamente. Os dados hemodinâmicos foram registrados no início do estudo, 10 minutos após a administração de FA, após a indução, após a intubação e 15 minutos após a intubação. Resultados A CE50 do propofol foi menor no Grupo C (2,32 µg.mL‐1, Intervalo de Confiança de 95% [95% IC] 1,85-2,75) e D (2,39 µg.mL‐1, 95% IC 1,91-2,67) do que no Grupo A (2,96 µg.mL‐1; 95% IC 2,55-3,33) (p = 0,023, p = 0,048, respectivamente). Não houve diferenças significantes na CE50 entre o Grupo B (2,53 µg.mL‐1, 95% IC 2,33-2,71) e o Grupo A (p > 0,05). Não houve diferenças significantes na Frequência Cardíaca (FC) entre os grupos A, B e C. A FC foi significantemente menor no grupo D do que no grupo A após a intubação (66 ± 6 vs. 80 ± 10 bpm, p < 0,01) e 15 minutos após a intubação (61 ± 4 vs. 70 ± 8 bpm, p < 0,01). Não houve diferenças significantes entre os quatro grupos na Pressão Arterial Média (PAM) em qualquer momento. A PAM dos quatro grupos foi significantemente menor após a indução, após a intubação e 15 minutos após a intubação do que na linha de base (p < 0,05). Conclusão FA em altas doses (0,75 mg.kg‐1 ou 1 mg.kg‐1) reduz a CE50 do propofol, e 1 mg.kg‐1 de FA reduz a FC durante níveis adequados de anestesia em pacientes não estimulados. Embora esse resultado deva ser investigado na presença de estimulação cirúrgica, sugerimos que a pré‐administração de FA pode reduzir a necessidade de propofol durante anestesia cuja profundidade seja monitorada pelo BIS.

Effect of ketamine and sufentanyl on respiratory depression induced by propofol in pediatric patients / 新乡医学院学报

Objective To compare the effect of ketamine and sufentanyl on respiratory depression induced by propofol in pediatric patients.Methods Sixty children with taplipes equines in the Department of Pediatric Orthopedics,the Third Affiliated Hospital of Zhengzhou University from February 2014 to August 2015 were selected and divided into ketamine group,sufentanil group and control group,with 20 patients in each group.The patients in ketamine group were given ketamine 1.50 mg· kg-1 by intravenous injection and maintained with ketamine 0.75 mg · kg-1 · h-1 by pump infusion;the patients in sufentanil group were given sufentanil 0.2 μg · kg-1 by intravenous injection and maintained with sufentanil 0.1 μg · kg-1 · h-1 by pump infusion;the patients in control group were given the same volume of saline.The initial plasma concentration of propofol in ketamine group,sufentanil group and control group was 1.1 mg · L-1,and the ratio between the two successive concentration gradients was 1.1.It was defined as positive when patients developed respiration depression.The bispectral index (BIS) and the observer's assessment of alertness/sedation (OAA/S) score of patients in the three groups were recorded at the time point of intravenous infusion ketamine or sufentanil (T1),3 min after propofol target controlled infusion (TCI) (T2),5 min after propofol TCI (T3) and after the target effect-site and plasma concentrations were balanced(T4).The target effect-site concentration was recorded when the BIS dropped to 65 or OAA/S score was 3.The median effective concentration(EC50) and its 95％ confidence interval (CI) of propofol inducing respiratory depression were calculated.Results There was no statistic difference in BIS and OAA/S scores of patients at the time point of T1 among the three group(P ＞ 0.05);the BIS and OAA/S scores of patients in ketamine group and sufentanil group were significantly lower than those in the control group at the time point of T2,T3 and T4 (P ＜ 0.05);the BIS and OAA/S scores of patients in ketamine group were significantly lower than those in the sufentanil group at the time point of T2,T3,T4 (P ＜ 0.05).The EC50 and its 95 ％ CI of respiratory depression induced by propofol in ketamine group,sufentanil group and the control group were 1.75 (1.56-2.34),1.86 (1.47-2.23),2.82 (2.56-3.02) mg · L-1 respectively.The EC50 of patients in ketamine group and sufentanil group was significantly lower than that in control group (P ＜ 0.05),but there was no statistic difference in EC50 of patients between the ketamine group and sufentanil group (P ＞ 0.05).Conclusion Both ketamine and sufentanil can increase the EC50 of respiratory depression induced by propofol in pediatric patients,but the effects of both drugs are the same.Ketamine and sufentanil can reduce the BIS and OAA/S scores of patients,enhance the sedation efficacy of propofol,and the effect of ketamine is better than sufentanil.

Effects of target-controlled infusion of dexmedetomidine on the median effective concentration of effect-site of propofol at loss of consciousness / 临床麻醉学杂志

Objective To investigate the effects of target-controlled infusion (TCI)of dexme-detomidine on the median effective concentration of effect-site (Ce50 )of propofol at loss of conscious-ness (LOC)in patients.Methods Sixty-four patients,28 males and 36 females,aged 20-60 years, ASA physical status Ⅰ or Ⅱ,scheduled for elective surgery,were randomly allocated to receive dexmedetomidine of 0 ng/ml (group P),dexmedetomidine of 0.4 ng/ml (group D1),dexmedetomi-dine of 0.6 ng/ml (group D2)and dexmedetomidine of 0.8 ng/ml (group D3)for 1 5 min before TCI of propofol,n =1 6 in each group.The propofol infusion was started to provide an effect-site concen-tration of 1.0 μg/ml,and increased by 0.2 μg/ml when propofol effect-site concentration and target concentration were equilibrium until LOC.Results The Ce50 (95%CI )at loss of consciousness in groups P,D1,D2 and D3 were 2.30 (2.24-2.36)μg/ml,1.92 (1.87-1.96 )μg/ml,1.60 (1.55-1.65)μg/ml and 1.41 (1.35-1.45 )μg/ml,respectively.There was a negative correlation between the effect-site concentration of propofol-induced LOC and target concentration of dexmedetomidine (r=-0.84,P <0.01).Compared with groups P,D1 and D2,the incidence of bradycardia was higher in group D3 (P <0.05).Conclusion The Ce50 of propofol-induced LOC gradually decreases with in-creasing target concentration of dexmedetomidine.Combining propofol with dexmedetomidine of 0.4 or 0.6 ng/ml that can reduce the Ce50 of propofol-induced LOC,which is suitable for induction of an-esthesia with a lower incidence of bradycardia.

Effects of ED50 of ropivacaine combined with sufentanil for spinal anesthesia in elderly patients / 临床麻醉学杂志

Objective To investigate the effects of median effective dose (ED50 )of ropivacaine combined with sufentanil for spinal anesthesia in elderly patients.Methods Forty-eight elderly patients (ASAⅠ-Ⅲ)scheduled for elective lower limb or perineum operation under spinal anesthesia were enrolled in this study.All patients were randomly divided into two groups:control group (group C)and sufentanil group (group S).L3-4 intervertebral puncture was selected for all patients.Anesthetic solution in group C was 0.5% ropivacaine,in group S was 0.5% ropivacaine and sufentanil,which was fixed at 5.0 μg,based on the experimental results and sequential principle.The ropivacaine dose of first patient in the control group was 9.0 mg,and in sufentanil group was 8.0 mg,followed by reducing the dose of ropivacaine,each time 1.0 mg.If the patient appeared invalid standards response,the previous one was selected as the first case. ED50 was determined by Dixon??s sequential method.Results The ED50 of sufentanil combined with ropiva-caine for spinal anesthesia in elderly patients with lower extremity or perineal surgery was 6.40 mg (95%CI:5.98-6.80 mg),ED50 of only ropivacaine was 8.42 mg (95% CI:7.79-9.03 mg).Compared with pre-dose,MAP at 3,6,15 min after treated in group C were decreased,and lower than those in group S (P <0.01).Conclusion Combined with 5.0 μg sufentanil in spinal anesthesia for lower limb or perineal surgery elderly,median effective dose of ropivacaine is reduced.

Target Effect-site Controlled Infusion of Propofol by Schnider Model: Comparison of Gender and Age / 대한마취과학회지

BACKGROUND: We investigated effect-site median effective concentration (EC50) of propofol for loss of consciousness and effect-site concentration at each anesthetic stage and awakening time to compare the differences by gender or age of patients using Schnider model. METHODS: Total 91 patients were allocated into 4 groups: male patients aged 18-34 year (Group 1), male patients aged 35-55 years (Group 2), female patients aged 18-34 years (Group 3) and female patients aged 35-55 years (Group 4). The effect-site EC50 for loss of consciousness was calculated and the effect-site concentration of propofol at each anesthetic stage and the awakening time of each group were recorded. RESULTS: The effect-site EC50 of propofol for loss of consciousness was 4.53 +/- 0.30microgram/ml, 4.60 +/- 0.25microgram/ml, 4.13 +/- 0.39microgram/ ml and 4.47 +/- 0.65microgram/ml in group 1, 2, 3, and 4, respectively. The effect-site concentrations in male patients aged 18-34 years were significantly higher than those in female patients. The awakening time of female patients aged 35-55 years was shorter than that of male patients. CONCLUSIONS: There were no significant differences of effect-site EC50 for the loss of consciousness of propofol with target effect-site controlled infusion by Schnider model among the groups. However the effect-site concentrations and the awakening time of propofol by Schnider model showed differences in patients' gender and age.

Discussion on EC50 of Ropivacaine Caudal Motor Block / 中国药房

OBJECTIVE:To discuss the median effective concentration(EC50)of ropivacaine caudal motor block. METHODS: The EC50 of ropivacaine caudal epidural block was determined with sequential experimental method. RESULTS:The EC50 of ropivacaine caudal block was 0.22%(95%CI ranged from 0.216% to 0.235%). CONCLUSION:Canales sacralis injected with 0.20%～ 0.22% ropivacaine is suitable for bladder endoscopic examination in out-patient.