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Bupivacaine is more cardiotoxic than lidocaine, particularly in the presence of acute respiratory acidosis. Ventricular arrhythmias and conduction disturbances may lead to cardiac arrest and death. Bupivacaine is considered a more potent cardiac sodium channel blocker because the channels recover more slowly than after lidocaine blockade. Amiodarone and possibly bretylium should be considered as the preferred alternative to lidocaine in the treatment of local anesthetic-induced ventricular tachyarrhythmias. Vasopressors may include epinephrine, norepinephrine, and vasopressin. Isoproterenol may effectively reverse some of the electrophysiological abnormalities characteristic of bupivacaine toxicity. The reason for the higher incidence of cardiotoxicity during pregnancy is unclear. Although total dose rather than concentration determines toxicity, the Food and Drug Administration no longer recommends 0.75% bupivacaine for anesthesia during labor.
布比卡因对心脏的毒性要大于利多卡因,尤其是在急性呼吸性酸中毒时。室性心律失常和传导障碍,可能会导致心脏骤停而死亡。布比卡因被认为是一种更有效的心脏钠通道阻滞剂,因为渠道比利多卡因阻滞后恢复更加缓慢。胺碘酮和溴苄胺也许应被视为在利多卡因局部麻醉诱导室性心动过速的治疗的首选治疗药。升压药可能包括肾上腺素,去甲肾上腺素和加压素。异丙可以有效地扭转一些布比卡因毒性的特征电生理异常。在怀孕期间的发病率较高的心脏的原因目前还不清楚。虽然浓度,而不是总剂量决定毒性,食品和药物管理局不再建议在分娩过程中使用0.75%布比卡因来麻醉。 |
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