Kaukinen S
Acta Anaesthesiol Scand. 1978;22(6):649-57. doi: 10.1111/j.1399-6576.1978.tb01349.x.
The effects of three concentrations of halothane or ketamine were investigated on isolated rabbit hearts, which were perfused with hydralazine, clonidine, propranolol or methyldopa. In hearts not subjected to the influence of an anaesthetic, clonidine was the only drug stimulating myocardial function. In those perfused with halothane or ketamine alone, both anaesthetics exerted a negative chronotropic and inotropic action in a dose-related manner. Ketamine markedly increased the coronary flow. Clonidine distinctly reduced the myocardial depression caused by halothane or ketamine. Hydralazine had no marked effects with either of these anaesthetics, except that it sensitized the hearts to the arrhythmic action of a high concentration of halothane. Propranolol, when combined with halothane, aggravated myocardial depression and decreased coronary flow. With ketamine, propranolol caused no other harmful interactions, apart from inhibiting the increase in coronary flow caused by this anaesthetic. Methyldopa intensified the myocardial depression induced by halothane, but tended to diminish that caused by ketamine. The results suggest that clonidine has a stimulatory cardiac action when combined with either of these anaesthetics. Disadvantageous interactions may exist between methyldopa or propranolol and halothane.
研究了三种浓度的氟烷或氯胺酮对离体兔心脏的影响，这些心脏用肼屈嗪、可乐定、普萘洛尔或甲基多巴灌注。在未受麻醉药影响的心脏中，可乐定是唯一能刺激心肌功能的药物。在单独用氟烷或氯胺酮灌注的心脏中，两种麻醉药均呈剂量依赖性地产生负性变时和变力作用。氯胺酮显著增加冠脉血流量。可乐定明显减轻氟烷或氯胺酮引起的心肌抑制。肼屈嗪对这两种麻醉药均无明显影响，只是它使心脏对高浓度氟烷的致心律失常作用更敏感。普萘洛尔与氟烷合用时，加重心肌抑制并减少冠脉血流量。与氯胺酮合用时，普萘洛尔除抑制氯胺酮引起的冠脉血流量增加外，未产生其他有害相互作用。甲基多巴增强氟烷引起的心肌抑制，但倾向于减轻氯胺酮引起的心肌抑制。结果表明，可乐定与这两种麻醉药中的任何一种合用时都具有刺激心脏的作用。甲基多巴或普萘洛尔与氟烷之间可能存在不利的相互作用。
