Computerized single-breath nitrogen washout: predicted values in a rural French community

Comparative manual and computer measurements of the alveolar N2 slope and closing volumes have indicated systematic differences. When a computerized system is used in field surveys, predicted values are to be obtained under the same conditions. Therefore, we measured the alveolar nitrogen slope (pha...

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Bibliographic Details
Published inLung Vol. 174; no. 1; p. 43
Main Authors Teculescu, D B, Damel, M C, Costantino, E, Buhler, O, Bohadana, A B, Marchand, M, Pham, Q T
Format Journal Article
LanguageEnglish
Published United States 1996
Subjects
Adolescent
Adult
Aged
Computers
Female
France
Humans
Lung - physiology
Male
Middle Aged
Nitrogen
Predictive Value of Tests
Pulmonary Alveoli - physiology
Respiratory Function Tests - methods
Retrospective Studies
Risk Factors
Rural Population
France
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Summary:Comparative manual and computer measurements of the alveolar N2 slope and closing volumes have indicated systematic differences. When a computerized system is used in field surveys, predicted values are to be obtained under the same conditions. Therefore, we measured the alveolar nitrogen slope (phase III, PIII), closing volume (CV), and closing capacity (CC) from single-breath N2 washout maneuvers in 158 healthy subjects (68 females), ages 21 to 64 years, from a rural community living in a nonpolluted area of northeast France. PIII, the CV to vital capacity ratio (CV:VC, %), and the CC to the total lung capacity ratio (CC:TLC, %) were regressed against age, height, weight, and the body mass index (BMI, kg/m2) and prediction equations with 95% confidence intervals were computed. PIII increased with age in both sexes and tended to decrease with height in males (r = -0.19, p = .08). The CV:VC and CC:TLC ratios depended on age and, in males, increased with the BMI. Despite accepting a 15% difference between the test VC and the spirometric VC, only 46.3% of asymptomatic nonsmokers produced a valid single-breath nitrogen washout (SBN2) test. This high failure rate limits the usefulness of the test for epidemiologic purposes when older populations "naive" to pulmonary function testing are studied under field-survey conditions.
ISSN:0341-2040