【摘要】 目的本研究探讨术前口服美托洛尔对丙泊酚麻醉时阿托品正性心率作用的影响。方法选择择期手术的全麻病人（ASAⅠ～Ⅱ）40例,随机分成两组,每组20例,第一组为实验组（M组）,术前口服美托洛尔50 mg,第二组为对照组（C组）给予安慰剂;麻醉诱导后以5 mg·kg^-1·h^-1的恒速灌注丙泊酚维持麻醉,待血流动力学稳定后静注阿托品,每次5μg/ kg,每次静注间隔2min,记录病人心率变化,直至病人心率升高达20bpm,阿托品总量限制在30μg/kg。结果实验组病人阿托品用量5μg/kg对心率没有明显变化,10μg/kg升高6 bpm±5 bpm;对照组用量在5μg/kg和10μg/kg,心率分别升高3 bpm±5 bpm和12 bpm±6 bpm,不同剂量组间差异存在统计学意义（P<0.05）。阿托品用量达到15μg/kg,对照组63%病人心率升高达到20bpm,实验组21%病人心率升高达到20bpm,组间差异存在统计学意义（P<0.05）。阿托品剂量达到30μg/kg,对照组90%和实验组79%病人心率升高达到20bpm,组间没有统计学差异（P>0.05）。结论术前口服美托洛尔50 mg减弱阿托品正性心率作用,该作用能够被大剂量阿托品有效逆转。更多还原

【Abstract】 Objective To investigate the effects of metoprolol on positive chronotropic effect of atropine during propofol anesthe- sia.Methods 40 ASA physical statusⅠandⅡadult patients （20 y-50 y）scheduled to undergo general anesthesia were enrolled in the study and allocated into two groups.One was metoprolol group （group M,n = 20）with a premedication of metoprolol,the other was control group （group C,n = 20）with a placebo tablet.After a stable hemedynamic state was obtained in each patient under propofol anesthesia with a rate of 5 mg·kg^-1·h^-1,all patients received incremental doses of atropine 5μg/kg over 5 s at 2 min intervals until HR increased by 20 bpm（beats per min）from their baseline values,whereas patients received additional atropine 5μg/kg when they did not attain an HR increase of 20 bpm.Total dose of atropine was limited to 30μg/kg.Results:In patients receiving metoprolol, HR did not change （-0.4 bpm±3 bpm ）with the dose of atropine of 5μg/kg,but increased by 6 bpm±5bpm when the cumulative atropine dose reached 10μg/kg.These changes in HR were significantly less than those in patients not receiving metoprolol in whom atropine 5μg/kg and 10μg/kg caused 3 bpm±5bpm and 12 bpm±6 bpm,respectively （P<0.05）.When the cumulative atropine dose reached 15μg/kg,HR of 12 patients （63 % ）had increased more than 20 bpm in group C,whereas only 4 of 19 patients （21 % ）in group M did the HR increase by more than 20 bpm （P<0.05 versus group C）.When the cumulative dose of atropine reached 30μg/kg,15 patients in group M （79%）and 17 patients in group C （90%）demonstrated HR increases of more than 20 bpm （P>0.05 between groups）.Conclusion:HR response to intravenous atropine is attenuated in humans receiving metoprolol 50 rag.The at- tenuated responsiveness to atropine can be effectively overcome by large dose atropine in most patients.更多还原