Durant P A, Joucken K
Br J Anaesth. 1984 Aug;56(8):917-20. doi: 10.1093/bja/56.8.917.
A 64-yr-old asthmatic patient underwent a two-vessel aortocoronary vein grafting. Before surgery, the patient received cimetidine 400 mg and labetalol 650 mg. During the first 60 min of bypass, hypotension (40-45 mm Hg) was observed in spite of phenylephrine 14 mg. This initial hypotension was followed, during rewarming, by a slow increase in arterial pressure to 150 mm Hg. On cessation of bypass, bronchospasm was observed and was protracted. It is assumed that labetalol clearance and metabolism were reduced by cimetidine, that labetalol alpha-antagonism was responsible for the vasodilatation withstanding the phenylephrine, and that a combination of labetalol beta-antagonism and phenylephrine alpha-agonism initiated the bronchospasm. These observations indicate that, after labetalol therapy, higher doses of vasopressor agents such as phenylephrine may be necessary, but that such therapy may lead to bronchospasm in asthmatic patients.
一名64岁的哮喘患者接受了双支血管主动脉冠状动脉静脉搭桥手术。术前，患者接受了400毫克西咪替丁和650毫克拉贝洛尔治疗。在体外循环的最初60分钟内，尽管使用了14毫克去氧肾上腺素，仍观察到低血压（40 - 45毫米汞柱）。这种初始低血压在复温过程中，随后动脉压缓慢升高至150毫米汞柱。体外循环停止时，观察到支气管痉挛且持续时间较长。推测西咪替丁降低了拉贝洛尔的清除率和代谢，拉贝洛尔的α受体拮抗作用导致血管扩张，抵消了去氧肾上腺素的作用，并且拉贝洛尔的β受体拮抗作用与去氧肾上腺素的α受体激动作用共同引发了支气管痉挛。这些观察结果表明，在使用拉贝洛尔治疗后，可能需要更高剂量的血管升压药如去氧肾上腺素，但这种治疗可能会导致哮喘患者发生支气管痉挛。
