Chassard D, Berrada K, Boulétreau P
Service d'Anesthésie-Réanimation, Hôpital de l'Hôtel-Dieu, Lyon, France.
Can J Anaesth. 1996 Apr;43(4):384-93. doi: 10.1007/BF03011719.
In vitro studies have demonstrated the potential advantages of alkalinization on anaesthetic activity, by decreasing the ratio of ionized to nonionized molecules, there by permitting more rapid penetration of local anaesthetic through biological membranes, thus decreasing the onset time. The proportion of each form depends on the pKa of the agent and the ultimate pH of the solution. When NaHCO3 is mixed with local anaesthetics, CO2 is produced. Carbon dioxide has been reported to enhance local anaesthetic action by diffusion trapping of the cationic form in pH gradient combined with a direct depressant action of CO2. The purpose of this study was to examine if clinical studies confirmed the in vitro action of alkalinisation.
The literature pertinent to alkalinization of local anaesthetics published in the major anaesthesia and pharmacology journals of North America and Europe.
While in vitro studies have demonstrated potential advantages for alkalinization on anaesthetic activity, clinical studies have shown that alkalinization of local anaesthetics produces inconsistent results. For bupivacaine and etidocaine, alkalinization of local anaesthetic solution can produce precipitation, thus limiting the feasibility of increasing the pH.
On the basis of this review, routine alkalinization of local anaesthetics is not recommended.
体外研究表明碱化对麻醉活性具有潜在优势，通过降低离子化分子与非离子化分子的比例，从而使局部麻醉药能更快速地穿透生物膜，进而缩短起效时间。每种形式的比例取决于药物的pKa和溶液的最终pH值。当碳酸氢钠与局部麻醉药混合时，会产生二氧化碳。据报道，二氧化碳通过在pH梯度中对阳离子形式的扩散捕获以及二氧化碳的直接抑制作用来增强局部麻醉作用。本研究的目的是检验临床研究是否证实了碱化的体外作用。
北美和欧洲主要麻醉学与药理学杂志上发表的与局部麻醉药碱化相关的文献。
虽然体外研究表明碱化对麻醉活性具有潜在优势，但临床研究表明局部麻醉药的碱化产生的结果并不一致。对于布比卡因和依替卡因，局部麻醉药溶液的碱化会产生沉淀，从而限制了提高pH值的可行性。
基于本综述，不建议常规对局部麻醉药进行碱化。
