[Effects of isovolaemic haemodilution on pulmonary gas exchange and haemodynamics (author's transl)].
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.
D000818:Animals; D003911:Dextrans; D004285:Dogs; D006438:Hemodilution; D006439:Hemodynamics; D010101:Oxygen Consumption; D011653:Pulmonary Diffusing Capacity; D012119:Respiration
D003911:Dextrans
Effekte der isovolämischen Hämodilution auf pulmonalen Gasaustausch und Hämodynamik.