[Hemodynamic modifications induced by volatile anesthetics halothane, penthrane, ethrane). II. Effect on myocardial contraction and myocardial response to hypoxia].

We had intended to reckon quantitatively the effects of volatile anaesthetics about myocardial contractility and coronary circulation, on rest and after total occlusion of the left circumflex coronary artery for 15 sec on young healthy mongrel dogs. Halothane decreases coronary flow of about 20% while Penthrane increase coronary flow (CF) of 30% after 20 sec and later it stabilizes to 10% higher than the control values. Ethrane causes a light initial decrease and later CF returns to control values. During occlusion, derivative of left ventricular pressure (LVP) is reduced from Halothane, which also causes a marked decrement of hyperemia. By means of penthranic anaesthesia, during occlusive phase, we observed a shortening in contraction and relaxation speed. Ethrane doesn't modify the hyperemic coronary flow nor cardiodynamic parameters during occlusive period, while the latter parameters are sensibly varying during restore.