Candido K D, Winnie A P, Covino B G, Raza S M, Vasireddy A R, Masters R W
Department of Anesthesiology, Lenox Hill Hospital, New York, New York, USA.
Reg Anesth. 1995 Mar-Apr;20(2):133-8.
In an effort to elucidate further the effect of alkalinization of bupivacaine on its anesthetic effect, a study was undertaken using alkalinized and non-alkalinized bupivacaine for lumbar plexus block and comparing the results with those obtained previously with brachial plexus block.
Thirty consenting adult patients about to undergo lower extremity surgery under regional anesthesia were selected for the study. All of the patients received an inguinal paravascular lumbar plexus block ("3-in-1 block"), along with a sciatic block to allow the anticipated surgery to be carried out. The patients were divided into two groups, one receiving plain "alkalinized" 0.5% bupivacaine; the other receiving plain "non-alkalinized" 0.5% bupivacaine. After each lumbar plexus block, the onset and duration of analgesia and anesthesia of the nerves derived from the lumbar plexus were determined by an independent investigator who was unaware of which solution had been administered.
There was no statistically significant difference between the two groups with respect to the onset or duration of anesthesia and analgesia.
The data obtained in the present study indicate that alkalinization of non-epinephrine-containing bupivacaine does not reduce the latency or increase the duration of analgesia or anesthesia after lumbar plexus block. Since most of the studies that do show such an effect of alkalinization were carried out using epinephrine-containing bupivacaine, it is postulated that in those studies alkalinization contributed to the decrease in latency and increase in duration, not so much by providing an increased amount of local anesthetic in the free base form, but by reactivating epinephrine's vasoconstrictor activity, which is inactivated by a low pH.
为了进一步阐明布比卡因碱化对其麻醉效果的影响，进行了一项研究，使用碱化和未碱化的布比卡因进行腰丛阻滞，并将结果与先前臂丛阻滞的结果进行比较。
选取30例同意接受区域麻醉下行下肢手术的成年患者进行研究。所有患者均接受腹股沟血管旁腰丛阻滞（“三合一阻滞”），并联合坐骨神经阻滞，以便进行预期的手术。患者分为两组，一组接受普通“碱化”0.5%布比卡因；另一组接受普通“未碱化”0.5%布比卡因。每次腰丛阻滞后，由一名不知道给予何种溶液的独立研究者确定腰丛神经镇痛和麻醉的起效时间及持续时间。
两组在麻醉和镇痛的起效时间或持续时间方面无统计学显著差异。
本研究获得的数据表明，不含肾上腺素的布比卡因碱化不会缩短腰丛阻滞后镇痛或麻醉的潜伏期，也不会延长其持续时间。由于大多数显示碱化有这种效果的研究是使用含肾上腺素的布比卡因进行的，因此推测在这些研究中，碱化有助于缩短潜伏期和延长持续时间，与其说是通过提供更多游离碱形式的局部麻醉剂，不如说是通过恢复肾上腺素的血管收缩活性，而肾上腺素的这种活性在低pH值下会失活。
