Clinical Trial: Single-Breath Measurement Underestimates Ventilatory Volume According to Emphysema Severity

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Single-Breath Measurement Underestimates Ventilatory Volume According to Emphysema Severity

Brief Summary: Although single breath helium (He) dilution measurement (VASB) is currently used in pulmonary function laboratories to assess functional alveolar volume and diffusing capacity for carbon monoxide, the extent to which VASB reflects ventilatory and thoracic volume has not been prospectively determined in emphysema. We hypothesized that VASB underestimates rebreathe helium dilution volume (VARB), and plethysmographic volume (VApleth) as clinical and physiologic severity of emphysema increases.

Detailed Summary: VASB, VARB, and VApleth were measured in 52 consecutive stable outpatients with clinical and radiographic emphysema. Thirteen patients with an obstructive ventilatory defect without emphysema (OVD) and 18 normal controls were similarly studied. All subjects underwent spirometry followed by whole body plethysmography and He dilution volume measurements; VASB and VARB order was randomized.
Sponsor: Columbia University

Current Primary Outcome:

• Difference between DLCO SB alveolar volume and the total lung volume measurement from plethysmography [ Time Frame: 10 seconds ]
  To test the hypothesis that DLCO SB underestimates DLCO derived by the re-breathe DLCO maneuver, and that VA SB similarly underestimates VA RB. Alveolar volume derived with the two maneuvers will be compared with body plethysmography, the gold standard of total lung volume measurement in patients with emphysema.
• Difference between DLCO RB alveolar volume and the total lung volume measurement from plethysmography [ Time Frame: 10 seconds ]
  To test the hypothesis that DLCO SB underestimates DLCO derived by the re-breathe DLCO maneuver, and that VA SB similarly underestimates VA RB. Alveolar volume derived with the two maneuvers will be compared with body plethysmography, the gold standard of total lung volume measurement in patients with emphysema.

Original Primary Outcome:

Current Secondary Outcome:

Original Secondary Outcome:

Information By: Columbia University

Dates:
Date Received: September 11, 2007
Date Started: January 2006
Date Completion:
Last Updated: July 2, 2015
Last Verified: July 2015