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Modeling a CO2 expirogram obtained with a forced expiratory maneuver
Author(s) -
Caucha Luis Jhony,
Cruz Julio Cesar,
Rueda Luis Antonio
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1063.5
Subject(s) - forced convection , expiration , functional residual capacity , residual volume , diffusion , tidal volume , volume (thermodynamics) , mechanics , convection , lung volumes , medicine , respiratory system , cardiology , chemistry , lung , thermodynamics , physics
The single path model used by Scherer et al. (J Appl Physiol.64:1022, 1988) to model the steady‐state CO 2 expirogram was here modified to fit the normal breath shown in the figure, left interrupted curve. It was modified to model a normal CO 2 expirogram and a forced maneuver (FASEB J. 23:1037.2, 2009) which required several regional parallel flows and the separation of the convection‐diffusion mechanism within the anatomical airway model of Weibel. The subject inhaled 1L of air from Functional Residual Capacity (FRC) and used 2.8s to exhale to FRC. The next breath, he used 0.75s to inhale the same volume from FRC and exhaled to Residual Volume (RV) in 3.75s. The experimental curves, interrupted lines, and the ones obtained with the model, continuous lines, are shown in the figure. The pulmonary blood flow was distributed from the 17th to 23rd generation and from the apex‐to‐base of the lung (A–B). The VD increase from A–B. The partitions of the convection‐diffusion for the normal breath were: first 8 generations for convection, 9–18 to convection‐diffusion and the last five generations for diffusion only. For the forced expiration were: first 7, 8–15, and the last eight, respectively. In conclusion, the dilution of CO 2 becomes more evident with the forced expiration and reveals the effect of CO 2 diffusion from the Expiratory Reserve Volume (ERV) to the VD for the normal breath, and from RV to ERV in the forced expiration.Supported in part by CEIS (Centro de Enseñanza, Investigación y Servicios).