Matsuoka S, Miyauchi Y, Nakatsu T, Yuasa Y, Ueda H, Miyao M
Jpn Circ J. 1985 May;49(5):499-506. doi: 10.1253/jcj.49.499.
The effects of respiratory acidosis on ventricular shunt flow and hemodynamics were studied in 20 anesthetized dogs with a ventricular septal defect and a normal pulmonary vascular bed. The interventricular shunt flow was measured directly by using a specially designed electromagnetic flow probe. Respiratory acidosis was produced by hypoventilation and tachypnea with constant minute volume. Hypoxemia was also induced by hypoventilation, but not by tachypnea with constant minute volume. Systemic vascular resistance was increased in severe hypoventilation at 100 and 50 ml of tidal volume, and tachypnea at 100 ml of tidal volume. However the increase of pulmonary vascular resistance was observed in only severe hypoventilation: arterial pH 6.9, PaO2 24 mmHg, and PaCO2 88 mmHg. Left to right ventricular shunt flow and pulmonary blood flow were increased significantly with no change of systemic blood flow in both conditions of respiratory acidosis. The diastolic fraction of shunt flow was increased significantly. These findings indicate that the increase of left to right shunt flow in respiratory acidosis might be one of the risk factors of congestive heart failure for the patients with ventricular septal defect.
在20只患有室间隔缺损且肺血管床正常的麻醉犬中，研究了呼吸性酸中毒对心室分流和血流动力学的影响。使用专门设计的电磁流量探头直接测量心室间分流流量。通过恒定分钟通气量的低通气和呼吸急促产生呼吸性酸中毒。低通气也会导致低氧血症，但恒定分钟通气量的呼吸急促不会导致低氧血症。在潮气量为100和50毫升的严重低通气以及潮气量为100毫升的呼吸急促时，全身血管阻力增加。然而，仅在严重低通气（动脉pH 6.9、PaO2 24 mmHg和PaCO2 88 mmHg）时观察到肺血管阻力增加。在两种呼吸性酸中毒情况下，左向右心室分流流量和肺血流量均显著增加，而全身血流量无变化。分流流量的舒张期分数显著增加。这些发现表明，呼吸性酸中毒时左向右分流流量的增加可能是室间隔缺损患者发生充血性心力衰竭的危险因素之一。
