Emphysema, Hypoxia and the Polycythemic Response

The circulation in patients with chronic bronchitis and emphysema at rest and during exercise, with special reference to the influence of changes in blood viscosity and blood volume on the pulmonary circulation.

“…It is normally assumed that polycythemia in patients with chronic bronchitis is due to hypoxemia (1,8), and a significant correlation has been shown between red cell volume and arterial oxygen saturation, both previously (8,9) and in the present study. Administration of oxygen for 6 weeks has been shown capable of restoring hematocrit and red cell volume to normal levels in initially polycythemic patients (35).…”

“…It has been shown that red cell volume is often slightly increased in patients with chronic bronchitis who have arterial desaturation (8,9), but judging by the hematocrit or hemoglobin values in other reports of large numbers of patients (10)(11)(12), substantial polycythemia is an uncommon complication. The present investigation is concerned with a highly selected group of patients with chronic bronchitis complicated by marked secondary polycythemia.…”

The red cell mass-arterial oxygen relationship in normal man

“…Relative hematocrit changes associated with decreases in Sao2 were considerably smaller than the parallel changes in red cell mass in this study, as the experience of others has shown (3,4). A fall in Sao2 which produced a 100%o increase in red cell mass, produced a relative increase of only 28%o in hematocrit.…”

“…Vanier et al (4), for example, concluded that the response of red cell mass to hypoxia was less than that in high altitude dwellers, whereas Shaw and Simpson (3), on the other hand, concluded that it was similar. Plasma volumes were found to be increased in both the series of Vanier et al (4) and Shaw and Simpson (3) who attributed these increases to the frequent existence of cor pulmonale or to a history of cor pulmonale in these groups. On the other hand, Hume and Goldberg (28) found lower plasma volumes in their patients with obstructive disease than in those of the control group.…”

“…This apparent absence of polycythemic response in these patients has led to some speculation regarding possible mechanisms of bone marrow suppression in chronic pulmonary disease. However, Shaw and Simpson (3) and Vanier, Dulfano, Wu, and Desforges (4) demonstrated that hypoxemia in chronic obstructive airway disease is in fact generally accompanied by an increase in red cell mass. They also pointed out that these increases in red cell mass are often not reflected in a rise in hematocrit or hemoglobin concentration because of an associated and variable plasma volume expansion.…”