
Accession Number : AD0666651
Title : MATHEMATICAL MODELS FOR THE ANALYSIS OF THE NITROGEN WASHOUT CURVE.
Descriptive Note : Technical rept. Jul 63Jan 67,
Corporate Author : SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX
Personal Author(s) : Rossing,Robert G. ; Danford,M. Bryan ; Bell,Earl L. ; Garcia,Raul
Report Date : NOV 1967
Pagination or Media Count : 63
Abstract : A general mathematical description of the washout of nitrogen from the lung during oxygen breathing is developed. From this, several specific mathematical models are derived and compared. These models each involve one of three different variables for description of the washout process: the alveolar dilution ratio, the specific tidal volume, or the rate constant. Two different types of models are considered: one involves a discrete distribution function of the basic variable; the other, a continuous distribution function. Several such models are applied to a series of washout curves as test problems. They are all found to be capable of fitting such curves with approximately equal precision. The choice between them must, therefore, be based on other factors such as theoretical suitability and ease of interpretation. On the basis of these criteria, the model suggested is one in which the alveolar dilution ratio manifests a Normal distribution, either unimodal or bimodal. Methods are developed for the calculation of certain indices from the parameters of this model. These indices may be of value in evaluating intersubject comparisons as well as intrasubject comparisons over time. Finally it is shown that these same indices may be calculated directly from the raw data, independent of any postulated distribution model. (Author)
Descriptors : (*RESPIRATION, MATHEMATICAL MODELS), NITROGEN, LUNG, DISTRIBUTION FUNCTIONS, OXYGEN
Subject Categories : Anatomy and Physiology
Distribution Statement : APPROVED FOR PUBLIC RELEASE