Pharmacodynamics Comparative Of Cis-atracurium And Rocuronium Administrated According To Body Surface Area And Weight

At present, the dose of muscle relaxant is mainly calculated by body weight and the ED95,we found that there were laege differences in the actual effect between different individual, especially between obese and thin patients, male and female, children and adults. The incidence of postoperative residual block is higher in elderly and obese patients.When both obese patients and normal body weight are administrated according to body weight, in the obese patients onset time is faster and the effect of muscle relaxant is stronger, particularly in longer aging. The reason may be that the dose calculated by body weight is too much.Obesity influences the efficacy of muscle relaxants have been reported. Some scholars proposed that muscle relaxants should be applied according to standard body weight. Drug effect is proportional to its plasma concentration, while the plasma concentration is related with blood volume and there is a linear relationship between body surface area and blood volume. In clinical disciplines such as chemotherapy is applied by body surface area. Would the muscle relaxant administered according to body surface area reduce the individual differences?Firstly, establish the dose-response curve of cis-atracurium and rocuronium to evaluate the ED95 in patients administrated according to body surface area,then compara the clinical efficacy and individual differences of cis-atracurium and rocuronium administered according to body weight and body surface area.There will be a reference for study and application in clinical.Part one The dose-effect relationship of cis-atracurium administered according to body surface areaObjective To establish the dose-response curve of cis-atracurium and to evaluate the ED50,ED75,ED9o,ED95 of cis-atracurium in patients administrated according to body surface area.Methods Eighty ASA I or II patients undergoing elective surgery under general anesthesia were enrolled in this study.Patients with neuromuscular disease were excluded and no patient was taking any drug that might influence the effect of muscle relaxant.General anesthesia was induced with propofol 2 mg/kg and fentanyl 3ug/kg.The patients were randomized to receive cis-atracurium 0.7mg/m2 (group C1),1.0mg/m2(group C2),1.3mg/m2(group C3),1.6mg/m2(group C4).Neuromuscular function was monitored with the transducer of force-displacement of HXD-Ⅰmultifunction monitor. The temperature of the thenar eminence surface was maintained at 32-34℃and body temperature at 36.0-36.9℃and room temperature at 22-25℃during the induction of anesthesia.The responses of adductor pollicis muscle were defined in terms of the percentages of maximal suppression in T1 of train-of-four(TOF) stimulation of ulnar nerve.According to log-probit transformation of the data of dose and response,the dose-response curve of cis-atracurium was established through linear regression.The onset time of cis-atracurium was also observed.Results No significant difference in sex,age,body weight,height,body mass index and body surface area among four groups (P>0.05).The percentages of maximal suppression of T1 rised when increasing the dose of cis-atracurium(P< 0.01). There was a significant change in onset time among four groups(P< 0.01),the onset time of 1.0 mg/m2,1.3 mg/m2 and 1.6 mg/m2 cis-atracurium was significantly shorter than that of 0.7 mg/m2 cis-atracurium.The ED50,ED75,ED9o,ED95 of cis-atracurium were 1.06,1.33,1.64 and 1.86mg/m2 respectively. Conclusion The ED50,ED75,DD90,ED95 of cis-atracurium are 1.06,1.33,1.64 and 1.86mg/m2 respectively. The onset time of CIS shortens while increasing dosage. Part two The dose-effect relationship of rocuronium administered according to body surface areaObjective To establish the dose-response curve of rocuronium and to evaluate the ED50,ED75,ED90,ED95 of rocuronium in patients administrated according to body surface area.Methods Eighty ASAⅠorⅡpatients undergoing elective surgery under general anesthesia were enrolled in this study.Patients with neuromuscular disease were excluded and no patient was taking any drug that might influence the effect of muscle relaxant.Anesthesia was induced with propofol 2 mg/kg and fentanyl 3ug/ kg.The patients were randomized to receive rocuronium 4mg/m2 (group R4),5mg/m2 (group R5),6mg/m2 (group R6),7mg/m2 (group R7).Neuromuscular function was monitored and recorded with the transducer of force-displacement of HXD-Ⅰmultifunction monitor.Body temperature was maintained at 36.0-36.9℃and room temperature at 22-25℃during the induction of anesthesia.The responses of adductor pollicis muscle were defined in terms of the percentages of maximal suppression in T1 of train-of-four(TOF) stimulation of ulnar nerve.According to log-probit transformation of the data of dose and response,the dose-response curve of rocuronium was established through linear regression.The onset time of rocuronium was also observed.Results There were no significant differences in sex,age,body weight,height,body mass index and body surface area among four groups (P> 0.05).The percentages of maximal suppression of T1 rised when increasing the dose of rocuronium(P< 0.01).No significant change in onset time among four groups(P> 0.05).The ED50,ED75,ED90 and ED95 of rocuronium were 4.90,6.03,7.41 and 8.32mg/ m2 respectively..Conclusion The ED50,ED75 ED90 and ED95 of rocuronium are 4.90,6.03,7.41 and 8.32mg/m2 respectively.In less than the ED95 increasing usage of ROC does not accelerate the onset time.Part three Pharmacodynamics comparative of cis-atracurium administrated according to body surface area and weightObjective To compara the clinical efficacy and individual differences of CIS administered according to body weight and body surface area.Methods Forty ASA I or II patients without any neuromuscular disease undergoing elective surgery under general anesthesia were randomly divided into two groups(group W and group B) according to the different administration method of calculating the amount,20 patients in each group. The responses of adductor pollicis to train of four(TOF) stimulation of ulnar nerve were monitored by HXD-Ⅰmultifunction.Anesthesia was induced with propofol 2mg/kg, fentanyl 3ug/kg, CISO.lmg/kg (group W) or 3.72mg/m2 (group B),and maintained with propofol given by TCI(target-controlled infusion) with the effect-site concentration set at 3-4ug/ml and increments fentanyl lug/kg as required. Before and after anesthesia induction, record systolic blood pressure(SBP), mean pressure (MAP) and diastolic blood pressure (DBP), heart rate (HR), pulse oxygen saturation (SpO2), bispectral index (BIS) and temperature (T); record intubating conditions, onset time, T1 maximum inhibition, the clinical role of time, recovery index, pharmacological effects of time. SPSS 13.0 were used to analyze the data. All data are reported as the mean±standard deviation.Comparisons between groups were made by student t-test. Differences were considered significant at P<0.05.Results No significant differences were found in general, hemodynamic changes, BIS, T, endotracheal intubation conditions,muscle relaxant effects and the amount of medicine between the two groups.There were no significant differences in the variability of T1 maximal inhibition, the onset time, clinical role of time, recovery index between the two groups.Compare with the group B, the differences of dosage between different individuals in group W were larger, whereas the pharmacological effects of time were smaller.Conclusion It can not reduce the individual differences of muscle relaxant effect to apply CIS according to body surface area. Part four Pharmacodynamics comparative of rocuronium administrated according to body surface area and weightObjective To compara the clinical efficacy and individual differences of ROC administered according to body weight and body surface area.Methods Forty ASA I or II patients without any neuromuscular disease undergoing elective surgery under general anesthesia were randomly divided into two groups(group W and group B) according to the different administration method of calculating the amount,20 patients in each group. The responses of adductor pollicis to train of four(TOF) stimulation of ulnar nerve were monitored by HXD-Ⅰmultifunction.Anesthesia was induced with propofol 2mg/kg, fentanyl 3ug/kg,ROC0.6mg/kg (group W) or 16.64mg/m2 (group B),and maintained with propofol given by TCI(target-controlled infusion) with the effect-site concentration set at 3-4ug/ml and increments fentanyl 1ug/kg as required. Before and after anesthesia induction, record systolic blood pressure(SBP), mean pressure (MAP) and diastolic blood pressure (DBP), heart rate (HR), pulse oxygen saturation (SpO2), bispectral index (BIS) and temperature (T); record intubating conditions, onset time, T1 maximum inhibition, the clinical role of time, recovery index, pharmacological effects of time. SPSS 13.0 were used to analyze the data. All data are reported as the mean±standard deviation. Comparisons between groups were made by student t-test. Differences were considered significant at P<0.05.Results No significant differences were found in general, hemodynamic changes, BIS, T, endotracheal intubation conditions and muscle relaxant effects. between the two groups.There were no significant differences in the variability of T1 maximal inhibition, the onset time, clinical role of time between the two groups.Compare with the group B, the differences of dosage between different individuals in group W were larger, whereas the pharmacological effects of time and recovery index were smaller. Meanwhile, the amount of medicine in group W was much more than than in group B.Conclusion It can not reduce the individual differences of muscle relaxant effect to apply ROC according to body surface area.However, the dosage can be reduced.