Abstract
Background: The ATS/ERS lung function testing guidelines (Brusaco, V. et al Eur Respir J 2005; 26: 720-735) recommend a 4 minute interval between diffusion tests to allow adequate gas clearance and prevent contamination of subsequent measures.
Objective: In the absence of supportive evidence, our pilot study of healthy normal subjects aimed to investigate whether there was any significant difference in DLCO measurements when tested at time intervals shorter (2mins) and longer (6 mins) than the recommended 4 minutes.
Methods: We recruited 30 healthy normal volunteers to participate in a prospective cross sectional study. Each underwent 3 visits: Visit 1 spirometry, haemoglobin, and DLCO, as per ATS/ERS reproducibility guidelines. Visits 2 and 3, DLCO only. DLCO time intervals were randomised to 2, 4, or 6 minute intervals per visit. Visits 1, 2, 3 performed within 7 days at ± 2 hours of initial visit.
Results: Baseline characteristics were all non smokers with mean age 38.1 years (10.9), FEV1 3.56L (0.84), FVC 4.34L (1.14). There was no significant difference in DLCO measurements at 2, 4, 6 minutes (NS). The Intraclass Correlation Coefficient was 99%.
Conclusion: These results suggest that DLCO measurements at 2, 4, 6 minutes are equivalent in healthy normals. Our preliminary data raises the possibility that the time taken to measure DLCO may be able to be shortened, however further investigation is required into specific disease states.
- © 2014 ERS