急性等容血液稀释对髋关节置换术病人靶控输注异丙酚时量相关半衰期的影响

Effect of acute normovolemic hemodilution on context-sensitive half-time for propofol given by target controlled infusion during hip joint replacement

目的探讨急性等容血液稀释(ANH)对靶控输注(TCI)异丙酚时量相关半衰期的影响。方法择期行髋关节置换术病人35例,年龄20～60岁,体重40～75kg,ASA Ⅰ或Ⅱ级,预计出血量大于1000ml,随机分为 ANH 组(n=17)和对照组(CON 组,n=18)。麻醉诱导后 ANH 组从颈内静脉放血,直至红细胞压积达26%,同时在30min 内静脉输注10ml·kg^(-1)林格氏液和6%羟乙基淀粉,CON 组仅静脉输注10ml·kg^(-1)林格氏液,平稳10min 后两组以恒定靶血浆浓度(3μg·ml^(-1))TCI 异丙酚60min。 TCI 前、TCI 2、5、10、20、30、40、50、60、80、100、120、150、180 min 采集桡动脉血,应用气相色谱-质谱联机测定异丙酚血药浓度。采用 NONMEN 软件进行多项非线性回归,得出最终回归模型为二室模型,计算异丙酚的时量相关半衰期、分布半衰期和消除半衰期。结果 ANH 后血红蛋白[(92±13)g·L^(-1)]、红细胞压积(26%±5%)均低于 ANH 前(P＜0.05),达中度血液稀释。与 CON 组比较,ANH 组在,TCI 不同输注时间异丙酚的时量相关半衰期、分布半衰期差异无统计学意义(P＞0.05),消除半衰期延长 (P＜0.05)。结论 ANH 对 TCI 异丙酚时量相关半衰期无影响。

Objective To investigate the effect of acute normovolemic hemedilution （ANH） on contextsensitive hull-time for propofol given by target controlled infusion （TCI） during hip joint replacement. Methods Thirty-five ASA Ⅰ or Ⅱ patients aged 20-60 yr weighing 40-75 kg undergoing elective hip joint replacement were randomized into two groups： ANH group （n = 17） and control group （n = 18）. In ANH group ANH was performed after induction of anesthesia by withdrawing blood from artery until Hct was reduced to 26 % . Blood volume was maintained by simultaneous IV infusion of lactated Ringer＇s solution （LR） and 6% HES. ANH was completed in 30 min. After 10 min of stabilization TCI of propofol was started and maintained for 60 min. The target plasma propofol concentration was set at 3 μg· ml^-1 . The TCI system consisted of a Graseby 3500 infusion pump controlled by Stelpump 1.07 software （Stellenbosch University South Africa） using the pharmacokinetic parameters published by Tacldey. In control group LR 10 ml· kg^-1 was infused over 30 min. TCI of propofol was started at 40 mill after induction of anesthesia. Arterial blood samples were taken at 2, 5, 10, 20, 30, 40, 50, 60, 80, 100, 120, 150 and 180 min after TCI of propofol was started for determination of blood concentration of propofol by gas chromatography-mass spectrometry （G C-MS） . Context-sensitive half-time, distribution half-time and elimination half-time were calculated and compared between the two groups. Results The two groups were comparable in regard to age, sex, bodyweight, height and the total amount of fluid infused. The differences in context-sensitive half-time and distribution half-time between the two groups were not statistically significant （ P 〉 0.05）. The elimination half-time was significantly longer in ANH group than in control group （ P 〈 0.05）. Conclusion ANH does not affect significantly the context-sensitive half-time and distribution haft-time for propofol given by TCI.