Uneven Ventilation as a Continuous Distribution Function of Alveolar Dilution.
Abstract
Replicate nitrogen washout curves recorded in 10 normal subjects were analyzed both by the classical Fowler model and by a model which treats the alveolar dilution ratio as being a continuously distributed variable. The majority of the curves could be satisfactorily fitted by assuming the distribution function to be single and Normal (Gaussian); less frequently a bimodal function was required which was composed of two Normal distributions. Pulmonary clearance delay (PCD) values were derived from each model and also by a method of calculation directly from the raw data. The values obtained by all three methods agreed very well, and the three methods may be regarded as equivalent and interchangeable. By any of the three methods, all subjects except one showed on at least one occasion a PCD less than 10%, but frequently the second of the paired determinations was somewhat higher (up to 30%). One subject, although considered normal on the basis of routine clinical testing, showed values which ranged from 30%-100% delay. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1971
- Accession Number
- AD0730279
Entities
People
- Philip D. Manfredi
- Robert G. Rossing
Organizations
- United States Air Force School of Aerospace Medicine