Pharmacokinetics and Concentration-effect Relationship after Propofol Infusion

Background: We investigated the pharmacokinetics (PK) and concentration - effect relationship after an infusion of propofol in order to obtain a model which can predict the time to eye opening. Methods: Anaesthesia was induced and maintained with propofol in 34 patients using a Computer Controlled Infusion Pump. Arterial blood samples were taken during recovery and a new model describing the PK was derived. The model was then used to predict the concentration of propofol at the time of eye opening to command. Results: The central volume of distribution was 0.228 L/kg, and the inter-compartment transfer rate constants (min^(-1)) were: k_(10) 0.166, k_(12) 0.091, k_(13) 0.124, k_(21) 0.045, and k_(31) 0.0098. The predicted concentration at which 50% of the patients responded to command was 0.98 μg/ml. Conclusions: PK parameters predicting propofol concentration during anaesthesia differ from those describing recovery. The PK of propofol during recovery following an infusion are similar to those following a bolus dose. Real time estimation of blood propofol concentration serves as a useful additional monitor of recovery from anaesthesia.

關鍵字

Anaesthetics, intravenous: propofol ； Metabolism, pharmacokinetics: concentration-effect

並列摘要

背景：為了尋找一個可以預計病人從麻醉後到能張開眼睛所需時間的propofol藥動學模式，本文作者在經電腦控制注射propofol後，研究了藥動學，藥物濃度和相對影響的關係。方法：34個病人，使用了電腦控制注射propofol麻醉。在甦醒室內，從動脈中抽取血樣本。從而得出一個藥動學模式。根據這藥動學模式來預計病人能張開眼睛的時間。結果：中央間隔室體積比例是0.228 L/kg，各跨間室隔傳送速度常數（min^(-1)）分別是：k_(10)0.166，k_(12)0.091，k_(13)0.124，k_(21)0.045和k_(31)0.0098。50％病人能對口頭指令有反應的藥物濃度估計是0.98 μg/ml。結論：在麻醉時，由藥動學所估計出的propofol濃度跟在甦醒室內有所不同。在甦醒室內，propofol在平均注射後及突擊量後兩種不同施藥方法後的藥動常數大致相同。在麻醉手術過程，血中propofol濃度的實時估計在甦醒室內是一種有用的輔助監察。

並列關鍵字

靜脈麻醉劑：propofol ；代謝，藥動學：濃度效應

國際替代計量

Pharmacokinetics and Concentration-effect Relationship after Propofol Infusion

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