[Effects of oxygen therapy on the hematocrit value in hypoxemic, chronic bronchopneumopathies].

Changes in haematocrit values were studied in hypoxaemic chronic bronchitis patients subjected to oxygen-therapy. A statistically significant decrease was observed in all cases after respiration of oxygen. This was partly attributable to resolution of vasoconstrictive reflexes imposed by prior oxygen starvation, due to shifting of part of the circulating mass from the systemic to the pulmonary circulation, and partly to improved ventilation yield; this, couplled with reduced cardiac frequency and output, facilitates a more efficient thoracic aspiration of the reflux blood.