Blood volume studies in chronic obstructive non-specific lung disease

Abstract

Blood volume studies.-in chronic hypoxic lung disease have produced conflicting results. Some have demonstrated that the red cell volume-hypoxic relationship is similar to that in normal subjects, whereas others have found that it is subnormal. Plasma volume has not been shown to be related to hypoxia. To elucidate this further, 45 patients with chronic obstructive bronchitis were studied. They were on average hypoxic at rest and on exertion, but mean values of red cell volume, plasma volume, venous haematocrit, red cell count, and haemoglobin concentration were normal. Red cell volume was linearly related to the degree of hypoxia, but the response was subnormal. Arterial oxygen saturation rather than tension was the main determinant of red cell volume, and resting values correlated better than exercise values with red cell volume. The best correlations were obtained when red cell volume was expressed as a function of the lean body mass rather than the total body weight. Red cell volume was also linearly related to arterial Co tension. Plasma volume did not correlate with any of the blood gases. The subnormal polycythaemic response to hypoxia may have been caused partially by latent iron deficiency and chronic infection; but severe hypoxia, hypercapnia, and gastrointestinal bleeding were not aetiological factors. The importance of tissue hypoxia in the regulation of the erythropoietic response and the reasons why previous blood volume studies have produced conflicting results are discussed.There is general agreement that -red cell volume, but not plasma volume, is linearly correlated with the level of hypoxia in healthy -subjects living at altitude (Shaw and Simpson, 1961;Weil, Jamieson, Brown, and Grover, 1968). Plasma volume is usually normal or slightly reduced at altitude (Hurtado, Merino, -and Delgado, 1945;Reynafarje, Lozano, and Valdivieso, 1959;Pugh, 1962;Weil et al., 1968).Blood volume studies in chronic obstructive non-specific lung disease have produced conflicting results. Some workers have concluded that red cell volume is not consistently elevated in a quantitatively normal manner for the level of hypoxia (Lemon,

Blood volume studies in chronic obstructive non-specific lung disease: a comparison of the bronchitic and emphysematous patients

“…This observation implies that the nature of the polycythaemic response to hypoxia in any particular group of patients with chronic obstructive non-specific lung disease depends on the relative proportions of the emphysematous and bronchitic types of which it is composed. This conclusion offers one possible explanation for the conflicting results of previous blood volume studies in these patients, with come workers maintaining that the polycythaemic response to hypoxia is subnormal (Vanier et al, 1963;Ayvazian, Richardson & Silber, 1969;Cocking & Darke, 1972a) and others that it is quantitatively normal (Shaw & Simpson, 1961;Lertzman, Israels & Cherniack, 1962;Hume, 1968). Other possible causes for these inconsistencies have been discussed previously (Cocking & Darke, 1972a).…”

“…This conclusion offers one possible explanation for the conflicting results of previous blood volume studies in these patients, with come workers maintaining that the polycythaemic response to hypoxia is subnormal (Vanier et al, 1963;Ayvazian, Richardson & Silber, 1969;Cocking & Darke, 1972a) and others that it is quantitatively normal (Shaw & Simpson, 1961;Lertzman, Israels & Cherniack, 1962;Hume, 1968). Other possible causes for these inconsistencies have been discussed previously (Cocking & Darke, 1972a). The two subgroups not only differed in respect of red cell volume and its relationship with the blood gases, but there was also a difference in the correla- tions between plasma volume and the degree of hypoxia; in the emphysematous group the two were unrelated, whereas a significant correlation was found in the more bronchitic patients.…”

Clinical features of polycythaemic patients with chronic obstructive non-specific lung disease

“…These features also did not account for the difference in red cell volume in the non-P and P patients, as their incidence was similar in the two groups, 15-2% of the non-P group and 16-7% of the P group being affected. CORRELATIONS In the patients as a whole, red cell volume was linearly correlated with Sao2 (r = -0-681, P<0-001) and Pao2 (r = -0-447, P<0-01) (Cocking and Darke, 1972). However.…”

“…Details of patient selection have been described previously (Cocking and Darke, 1972 (MRC, 1966) was completed and a full clinical examination was carried out. Posteroanterior and lateral chest radiographs were examined by an independent expert (R.G.G.…”

“…TLC' and RV' were measured with a Godart Pulmometer and TF by the steady state method; TF measurements were also standardized for a haemoglobin concentration of 14-6 g/100 ml and an alveolar capillary tension of 110 mmHg using the formula of Cotes et al (1972) described below in the discussion. The following investigations were also performed by methods described previously (Cocking and Darke, 1972)arterial blood gases, venous haematocrit, red cell count, haemoglobin concentration, serum iron concentration and unsaturated iron binding capacity, daily dietary iron intake, alimentary blood loss, and red cell and plasma volume (expressed as a percentage of the predicted normal values). In addition blood gases were determined in 22 haematologically normal control subjects who were free of cardiorespiratory disease.…”