Erythrocyte fragility is not altered in stable chronic obstructive pulmonary disease with normal arterial pH.

The aim of this study is to investigate if erythrocyte fragility is altered in chronic obstructive pulmonary disease (COPD) due to oxidative stress. Fasting blood samples were collected into both plain tubes and tubes with K(3) EDTA and analyzed in two hours for hematologic indexes and erythrocyte osmotic fragility (EOF). Malondialdehyde (MDA) concentrations in serum were detected in terms of TBARS (thiobarbituric acid reactive substances), spectrophotometrically. Thirty-nine clinically stable male COPD patients with mean age 67+/-8 were prospectively studied. The control subjects consisted of healthy males with mean age 64+/-12. Pulmonary function tests of COPD patients revealed severe airway obstruction whereas they were normal for control group. Normal pH with mild hypoxemia and hypercapnia were detected in arterial blood gas analyses. Hemoglobin, haematocrit and mean corpuscular volume values of two groups were similar. Mean serum MDA concentration was 1.09+/-0.11 micromol/l in COPD patients and 0.95+/-0.06 micromol/l in the control group (p=0.336). EOF was 33.06+/-1.24% in COPD group and 33.17+/-1.55% in controls (p=0.453). There was no correlation between EOF and MDA concentrations of COPD patients (r=-0.18, p=0.924). EOF and MDA did not correlate with severity of COPD (p>0.05). We conclude that markers of oxidative stress are not increased and erythrocyte osmotic fragility is not altered in stable COPD patients with normal arterial pH.