Differences Of Rocuronium Pharmacodynamics Between Obesity And Normal Women

Part? Differences of Pharmacodynamics between obesity and normalwomen with Induction Dose RocuroniumObjective: To evaluate the differences of rocuronium pharmaco-dynamics between obese obesity and normal women.Methods: Fourty women patientsunder general anesthesia, aged 18-45 yr, ASA physical status I or II, schedualed for elective surgery, time of surgery <1.5h, were included in the study. All the patients were without heart, brain, pulmonary,hepatic,renal, endocrine system disease and received no drugs which affected neuromusclar transmission.There were no problems about neuromuscular transmission function and water, electrolyte,and acid-base balance. Preoperative assessment criteria were not difficult airway.The petients with body mass index of 20-25kg/m² as group N_. Another 20 patients with body mass index of 30-35kg/m² as group B_. After entering the operation room, routine monitoring such as electrocardiogram?ECG?, heart rate?HR?, bispectral index?BIS?, pulse oxygen saturation?Sp O₂?, end-tidal carbon dioxide partial pressure and non-invasive blood pressure were monitored. We used TOF-Watch? SX Monitor to obseve the neuromuscular function. Anesthesia was induced with iv midazodam 0.03-0.05mg/kg, sulfentanil 0.3-0.5?g/kg, remifentanil plasma target concentration 4ng/ml and propofol 3?g/ml. The response of the adductor pollicis was defined by TOF stimulation of the ulnar nerve after loss of consciousness. The patients recived rocuronium 0.6mg/kg. BIS value was maintained at 40-60 and P_ETCO₂ was maintained at 35-45 mm Hg. The intubation condition was evaluated using Cooper's score and recorded. Onset time, clinical duration,recovery index and time of pharmacological action were recorded.1 There were no statistically significant differences in age and height between the two group?P>0.05?.2 The onset time,clinical duration, recovery index and time of pharmacological action of rocuronium were 102.6±16.2s, 41.8±5.0min, 11.4± 2.7min and 62.0±8.1min, respectively, in group N and were 96.0±8.0s, 54.9± 7.1min,16.5±2.1min,and 83.7±9.4min. respectively, in group B_. Compared with group N_, clinical duration, recovery index and time of pharmacological action were prolonged in group B_.Conclusion: The effective duration of induce does of rocuronium is longger in obese women patients than normal women patients. Part ? The determination of does-response curve of rocuronium in obese and normal body weight patientsObjective:To illustrate the difference of does-response curve of rocuronium and calculate the ED₅₀,ED₇₅,ED₉₀ and ED₉₅ in obese and normal women patients.Methods:Eighty women patients under general anesthesia, aged18⁴5yr, ASA physical status I or II, schedualed for elective surgery. time of surgery<1.5h, were included in the study. All the patients were without heart,brain,pulmonary,hepatic,renal, endocrine system disease and received no drugs which affected neuromusclar transmission.There were no problems about neuromuscular transmission function and water, electrolyte,and acid-base balance. Preoperative assessment criteria was not difficult airway. The petients with body mass index of 20²5kg/m² as group N were randomized to divided group N₁(1/4ED₉₅),group N₂(1/3ED₉₅),group N₃(1/2ED₉₅),group N₄(1ED₉₅), Another 40 patients with body mass index of 30-35kg/m² as group B and were randomized to divided group B₁(1/4ED₉₅),group B₂(1/3ED₉₅),group B₃(1/2ED₉₅),group B₄(1ED₉₅).Before the operation, routine monitoring such as electrocardiogram?ECG?, heart rate?HR?,bispectral index?BIS?, pulse oxygen saturation?Sp O₂?,end-tidal carbon dioxide partial pressure(P_ETCO₂) and non-invasive blood pressure were monitored. We used TOF-Watch? SX Monitor to obseve the neuromuscular Results:function. Anesthesia was induced with iv midazodam 0.03-0.05mg/kg, sulfentanil 0.3-0.5?g/kg, remifentanil plasma target concentration 4ng/ml and propofol 3?g/ml.After the patients lost consciousness, calibration was carried out. When the first twitch height?T1? was 100%,group N_1-4 and group B_1-4 patients were injected rocuronium 0.075,0.1,0.15,0.3mg/kg respectivly. When the T1 reached the maximum,all the patients were injected rocuronium to 0.6mg/kg. BIS value was maintained at 40-60 and P_ETCO₂ was maintained at 35⁴5mm Hg. The relationship between probit-transformed depression of first twich height of TOF?T1? and the logarithm dose of rocuronium was analysed by linear regression. ED₅₀, ED₇₅, ED₉₀ and ED₉₅ of rocuronium in obese and normal body weight patients were calculated.Results:1 There were no statistically significant differences in age and height?P>0.05?,but body mass index difference was statistically difference?P<0.05? between the two group.2 T1 maximum inhibition degree of group N and B were increased with the increase of the dosage?P<0.05?.Under the same first dose,the T1 maximum inhibition degree of group B was greater and the onset time was shorter than group N .But thier was no statistically difference?P>0.05?.3 Does-response curve equations of the both groups were Y1=3.464X1-2.23 and Y2=3.843X2-2.750 respectively. The curve regression coefficient was statically significant?P<0.05?. The ED₅₀, ED₇₅, ED₉₀ and ED₉₅ of rocuronium were 0.122 mg/kg, 0.176 mg/kg, 0.25mg/kg and 0.324mg/kg, respectively, in normal body weight group, and were 0.103mg/kg, 0.145mg/kg, 0.201mg/kg and 0.251mg/kg, respectively, in obese group. The ED₅₀, ED₇₅, ED₉₀ and ED₉₅ of rocuronium in group B were smaller than group N ?P<0.05?.Conclusion:Obesity factor significantly affects the dose-response curve of rocuronium and Obese patients increase the sensetivity of the reaction to rocuronium.