Teichmann J, Klöpper M, Larsen R, Radke J, Kettler D
Anaesthesist. 1978 Oct;27(10):459-64.
In experiments on 11 closed chest dogs the behaviour of pulmonary gas exchange and haemodynamics during isovolaemic haemodilution with 6% dextran was studied. The dogs were ventilated artificially (IPPB, PEEP = 0) with room air. After haemodilution a slight increase of arterial PO2 from 86 to 92 mm Hg was found. In another series of experiments an inspiratory O2-concentration of 25% was applied resulting in an increase of arterial PO2 from 106 to 113 mm Hg. In both series a decrease of alveolararterial PO2 gradients was observed. Effective pulmonary capillary blood flow varied in accordance with changes of cardiac output. Thus intrapulmonary shunt is supposed to have remained constant. The changes of pulmonary O2 diffusing capacity could be explained by the effect of haemodilution per se. At the end of the experiments ventilation was changed by adding a positive endexpiratory pressure of 8 cm H2O resulting in a decrease of arterial PO2 and a steep fall of cardiac output. In conclusion, isovolaemic haemodilution leads to only negligible variations of pulmonary gas exchange which should not be of any clinical importance.
在对11只闭胸犬进行的实验中，研究了用6%葡聚糖进行等容血液稀释期间肺气体交换和血流动力学的变化。犬用室内空气进行人工通气（间歇性正压通气，呼气末正压=0）。血液稀释后，发现动脉血氧分压从86毫米汞柱略有升高至92毫米汞柱。在另一系列实验中，应用25%的吸入氧浓度，使动脉血氧分压从106毫米汞柱升高至113毫米汞柱。在这两个系列中，均观察到肺泡-动脉血氧分压梯度降低。有效肺毛细血管血流量随心输出量的变化而变化。因此，推测肺内分流保持不变。肺氧弥散能力的变化可以用血液稀释本身的作用来解释。实验结束时，通过增加8厘米水柱的呼气末正压来改变通气，导致动脉血氧分压降低和心输出量急剧下降。总之，等容血液稀释导致肺气体交换的变化微不足道，不应具有任何临床重要性。
