Single-Breath Measurement Underestimates Ventilatory Volume According to Emphysema Severity
| Status: | Completed |
|---|---|
| Conditions: | Chronic Obstructive Pulmonary Disease, Pulmonary |
| Therapuetic Areas: | Pulmonary / Respiratory Diseases |
| Healthy: | No |
| Age Range: | 18 - 81 |
| Updated: | 4/21/2016 |
| Start Date: | January 2006 |
| End Date: | July 2008 |
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.
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.
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.
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.
Inclusion Criteria:
- All outpatients between the ages of 18 and 81 years referred to the Columbia
University Medical Center Pulmonary Diagnostic Unit between 1/18/06 and 7/30/07 for
full pulmonary function evaluation, and with an obstructive ventilatory defect on
spirometry, were considered eligible.
Exclusion Criteria:
- Patients who did not want to undergo the re-breathe diffusing capacity testing
- Patients who could not give informed consent;and
- Patients who were too physically compromised to undergo full testing including the
re-breathe maneuver as deemed by our technicians.
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