Single-Breath Measurement Underestimates Ventilatory Volume According to Emphysema Severity

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.

Study Overview

• Status: Completed
• Conditions: Emphysema

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 73

Contacts and Locations

Study Locations

• United States
  • New York
    • NY, New York, United States, 10032
      • Columbia University Cardiopulmonary, Sleep and Ventilatory Disorders Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 81 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

This is a prospective trial in all outpatients with emphysema referred for full pulmonary function testing to the pulmonary diagnostic unit.

Description

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.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Cohort A; Patients with obstructive defects and radiological evidence of emphysema
Cohort B; Patients with obstructive ventilatory defects and no radiological evidence of emphysema
Cohort C; Non-smokers without obstructive ventilatory defects or history of cardiopulmonary disease

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference between DLCO SB alveolar volume and the total lung volume measurement from plethysmography	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.	10 seconds
Difference between DLCO RB alveolar volume and the total lung volume measurement from plethysmography	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.	10 seconds

Collaborators and Investigators

• Sponsor: Columbia University
• Investigators: Principal Investigator: Robert C Basner, MD, Columbia University

Study record dates

Study Major Dates

• Study Start: January 1, 2006
• Primary Completion (Actual): July 1, 2008
• Study Completion (Actual): July 1, 2008

Study Registration Dates

• First Submitted: September 11, 2007
• First Submitted That Met QC Criteria: September 12, 2007
• First Posted (Estimate): September 14, 2007

Study Record Updates

• Last Update Posted (Estimate): July 7, 2015
• Last Update Submitted That Met QC Criteria: July 2, 2015
• Last Verified: July 1, 2015

More Information

Terms related to this study

• Keywords: emphysema; pulmonary function testing; alveolar volume
• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema; Emphysema
• Other Study ID Numbers: AAAB6328