Lung diffusing capacity for nitric oxide and carbon monoxide: dependence on breath-hold time.

Abstract

BACKGROUND:

The combined measurement of diffusing capacity of the lung for nitric oxide (Dlno) and diffusing capacity of the lung for carbon monoxide (Dlco) is a simple, noninvasive tool, but methodologic factors might influence results and reproducibility. We thus quantified the influence of breath-hold time on Dlco and Dlno in subjects with or without airway disease.

METHODS:

Simultaneous single-breath measurements of Dlco and Dlno were performed in 10 patients with cystic fibrosis (CF) [mean +/- SD age, 33 +/- 9 years; FEV(1), 69 +/- 28% of predicted] and 10 healthy subjects (age, 31 +/- 9 years; FEV(1), 108 +/- 8% of predicted), using the Masterscreen PFT (Viasys/Jaeger; Höchberg, Germany), with 45 ppm of inspired nitric oxide (NO), and breath-hold times of 4 s, 6 s, 8 s, and 10 s. The last two of three consecutive measurements were used for analysis.

RESULTS:

In healthy subjects but not patients with CF, Dlno, and Dlco differed significantly (p < 0.05 each) between breath-hold times. Differences primarily occurred at 4 s and 10 s, while at 6 s and 8 s alveolar volume (VA), Dlno, Dlco, and Dlno/Dlco were similar. Variability of consecutive measurements (either three or the last two measurements) did not depend on breath-hold time. At 8 s, mean variabilities of Dlno and Dlco in healthy subjects were 4.9% and 2.5%, respectively, and 4.2% and 3.2% at 6 s. At 8 s, mean variabilities of Dlno and Dlco in CF patients were 4.4% and 1.9%, and 7.4% and 3.3% at 6 s.

CONCLUSIONS:

Single-breath determinations of dlno and dlco showed no difference between breath-hold times of 6 s and 8 s in subjects with or without airway obstruction, and reproducibility was acceptable. Standardization of breath-hold time for Dlno measurements seems important for clinical and research comparisons.

• Authors: Holger Dressel, Laura Filser, Rainald Fischer, Dorothea de la Motte, Werner Steinhaeusser, Rudolf M Huber, Dennis Nowak, Rudolf A Jörres
• Journal: Chest (Chest) Vol. 133 Issue 5 Pg. 1149-54 (May 2008) ISSN: 0012-3692 [Print] United States
• PMID: 18263682 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Nitric Oxide
• Carbon Monoxide

Topics

• Administration, Inhalation
• Adult
• Airway Obstruction (etiology, physiopathology)
• Breath Tests (methods)
• Carbon Monoxide (administration & dosage)
• Cystic Fibrosis (complications, physiopathology)
• Female
• Follow-Up Studies
• Forced Expiratory Volume (drug effects, physiology)
• Humans
• Male
• Nitric Oxide (administration & dosage)
• Prognosis
• Pulmonary Diffusing Capacity (drug effects, physiology)
• Respiration (drug effects)
• Severity of Illness Index
• Spirometry (methods)
• Time Factors