Ph.D., University of Washington (Seattle), 1968

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Research Interests

Nonlinear lung mechanics.

Description of Research

We have developed a model for the pressure-volume hysteresis in lungs. We have presented experimental evidence (Frazer et al., Respiration Physiol. 43: 237-246, 1981 and 61: 277-288, 1985.) that the hysteresis present in quasistatic volume-pressure curves of excised rat lungs, for the most part, depends on (1) the opening (recruitment or "on" transition) of closed lung units during inflation from low end-expiratory pressures, (2) the subsequent monotonic expansion of open lung units during continued inflation, (3) monotonic contraction of open lung units with deflation, and (4) closing (derecruitment or "off" transition) of open lung units with continued deflation to low end-expiratory pressures. Our mathematical model reproduces all the major qualitative aspects of the experiments.

Recent Publications

W. Cheng, D.S. DeLong, G.N. Franz, E.L. Petsonk and D.G. Frazer. Discontinous Lung Sounds and Hysteresis in Control and Tween 20-rinsed Excised Rat Lungs. Respir Physiol 117: 131-140, 1999

L. Brancazio, G.N. Franz, E.L. Petsonk, and D.G. Frazer. Lung Area-Volume Models in Relationship to the Recruitment-Derecruitment of Individual Lung Units. Annals of Bioengineering 29:1-11, 2001