[Dyspnea, respiratory mechanics and gas exchange in patients with idiopathic pulmonary fibrosis].

The sensation of dyspnea on exertion is usually the first clinical symptom in patients with IPF. The aim of the study was to assess breathlessness in patients with IPF at the time of diagnosis. The study group included 9 patients (5 women and 4 men), aged 61.4 +/- 10.5 (mean +/- SD) yrs, (range 38-71 yrs). FVC was 65.8 +/- 8.3% pred., FEVI 70.0 +/- 9.0% pred., TLC 65.1 +/- 10.5% pred. 6 min walking test was performed, during which pts reported their breathlessness according to Borg scale. All patients but one reported breathlessness during exercise. Patients were divided into two groups according to the level of dyspnea at the end of the walking test. Patients with dyspnea equal or less than moderate (= < level 3 Borg scale) had significantly higher lung volumes FVC (2.57 +/- 0.44 vs 1.79 +/- 0.5 l, p < 0.05), FEVI (2.23 +/- 0.29 vs 1.56 +/- 0.36 l, p < 0.02), TLC (4.26 +/- 0.26 vs 3.13 +/- 0.69 l, p < 0.02), DLCO (4.49 +/- 0.52 vs 3.43 +/- 0.23 mmol/min/kPa, p < 0.02), and smaller alveolar-arterial oxygen tension difference at rest (31.8 +/- 5.6 vs 43.8 +/- 2.8 mmHg, p < 0.01) as compared to the patients with more severe dyspnea (> level 3 Borg scale). All patients desaturated during the test, but there was no correlation between the degree of desaturation and dyspnea level at the end of the test. 4 patients from the first group (dyspnea level = < 3 Borg scale) desaturated from 6.3% to 19.4% from baseline value. So patients with IPF may experience severe desaturation during normal daily activity not being aware of it. Dyspnea on exertion in these patients seems to depend on both disturbed lung mechanics and gas exchange. Simple 6-minutes walking test proved to be useful in assessing severity of the disease in patients with IPF.