Changes of Propofol Levels in Isolated Cardiopulmonary Bypass Circuit

Propofol在離體體外心肺循環系統內之濃度變化

蘇浩博(Haw-Bow Su) ； 曾稼志(Chia-Chih Tseng) ； 鄭誠德(Cherng-Teh Jenn) ； 張傳林(Chuan-Lin Chang) ； 黃金鼎(Jin-Ding Huang)

《Acta Anaesthesiologica Sinica》 34卷1期 (1996/03) Pp. 17-20

https://doi.org/10.6955/AAS.199603.0017

摘要

Background: High dose fentanyl anesthesia in cardiac surgery has been supplemented with propofol to prevent patient's awareness and recall. It has been known that during cardiopulmonary bypass (CPB), fentanyl or midazolam concentration decreases, except for propofol where it remains unknown. This study evaluated the interaction between propofol and the CPB circuit in vitro. Methods: Three identical experiments were conducted. In each experiment we used a set of CPB circuit composed of a standard 3/8 inch PVC tubing trap, a reservoir and a pump. The reservoir was primed with 2,000 ml solution of 2.5% dextrose and 0.45% NaCI in which 20 mg propofol was added. The solution was circulated in the circuit at a flow rate of 2 L/min. The experimental period was 30 min. A 5 ml sample of the solution was taken from the venous sampling site of the circuit immediately prior to the experiment, and thereafter each from the arterial and venous sampling sites at 1, 3, 5, 10, 20 and 30 min after the start of the experiment. The samples were kept at 4°C and assayed by HPLC. Results: The propofol concentrations decreased exponentially with the increase of experimental time. There were no significant differences in the concentrations and the rates of decrease between the arterial sampling site and the venous sampling site. The decrease was 20% at 1 min, 68% at 10 min, 83% at 20 min, and 92% at 30 min after the beginning of the experiment. Conclusions: The results demonstrate the presence of propofol sequestration by the CPB circuit. Evaporation in the bubble oxygenator, absorption by and/or adherence to the circuit are suspected as the possible causative factors.

關鍵字

Anesthesia, intravenous: propofol ； Extracorporeal circulation: cardiopulmonary bypass (CPB), bypass circuit ； Biopharmaceutics: pharmacokinetics

並列摘要

背景：Propofol用於心臟外科手術之麻醉以取代diazepam類藥物使病人進入安眠以及避免術中清醒之發生已有相當多文獻報告，其優點為藥物代謝快速易於掌握，且甦醒容易，並具有中樞神經保護作用等。常用的fentanyl與midazolam已知可被體外心肺循環系統所吸附而導至濃度降低。但propofol在體外心肺循環系統內之濃度變化如何尚未得知。本實驗之設計即在觀測其變化。方法：本實驗觀測三組體外心肺循環系統。每組系統是由3/8＂口徑的管路，William Harvey H-1700 bubble oxygenator，以及氣泡收集器所組成。循環機幫浦啟動前，先加入含有20 mg propofol的0.25％ glucose water 2,000 ml。在時間零分時，從循環系統靜脈端抽取樣本5 ml，然後啟動幫浦，流速定於2L/min在室溫下，其餘樣本抽取方法為動、靜脈端各5 ml，時間為1, 3, 5, 10, 20, 30分，樣本抽取後儲存於4℃，分析方法為高效能液相色層分析（HPLC）。結果：在第一次循環propofol濃度減少20％，10分鐘後減少68％，到30分鐘後，propofol濃度減少92％。其降低主要原因可能是吸附在體外循環的人工及其迴路內。結論：Propofol在經過人工肺後濃度確會降低其原因尚待進一步研究。再者由於本結果是得自離體體外心肺循環系統，其在人體上的變化，亦待進一步的研究。

並列關鍵字

靜脈麻醉劑：propofol ； 體外循環：人工肺，心肺分流 ； 生物製藥學：藥物動力學