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多巴胺是去甲肾上腺素的前身,它与去甲肾上腺素和异丙肾上腺素一样,对心脏有同等程度的阳性变力性作用,但却没有去甲肾上腺素那样对末梢血管α受体的兴奋作用和异丙肾上腺素的增加心率作用。因此,它可增强心肌收缩力而对血压和心率仅有较小的影响。然而,其作用可因药物剂量不同而表现出明显差异,低浓度时(5μg/kg/min 以下),心率和血压可无变化,心排血量却增加,当剂量为10μg/kg/min 时,心率加快,血压升高,心排血量反而减少。同时,有人报告,尚有增加心律失常的危险(室性心律失常)。
Dopamine is the predecessor of norepinephrine, which, like norepinephrine and isoprenaline, has the same degree of positive variability on the heart but no excitability of norepinephrine on the peripheral vascular alpha receptors Role and isoproterenol increase heart rate effect. Therefore, it increases myocardial contractility with only a small effect on blood pressure and heart rate. However, its effect may be significantly different due to different doses of the drug. At low concentrations (5μg / kg / min or less), heart rate and blood pressure may not change and cardiac output may increase. When the dosage is 10μg / kg / min , Heart rate, blood pressure, cardiac output decreased. In the meantime, it has been reported that there is an increased risk of arrhythmia (ventricular arrhythmias).