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Analysis of lung expansion based on PL-VL curves and models of lung unit recruitment.
Frazer DG; Afshari AA; Goldsmith WT; Franz GN
FASEB J 1996 Mar; 10(3):A806
In the past, a simple model of the lung based on three distinct regions of a normalized lung P(L)-V(L) curve was proposed (Frazer et al., Respir. Physio. 61:277, 1981). This model assumes that total lung volume, V(L), is composed of N(o) open lung units having volume V(u)((V(L)=N(o)V(u)). The normalized pressure volume curve of each lung unit is assumed to be similar to the normalized lung deflation curve having a minimal amount of hysteresis. The distribution function representing the normalized number of open units as the lung was inflated was calculated assuming [N(o)/N(omax)]=[V(L)/V(Lmax)]/[V(u)/V(umax)], where V(L)/V(Lmax)] was the normalized inflation curve and V(u)/V(umax) was equal to the normalized deflation curve in the open region. When the normalized number of open lung units was plotted as a function of V(L), it was found that [N(o)/N(omax)]=V(L)F =V(L)0.9. Since we have shown previously that [N(o)/N(omax)]=[V(L)/V(Lmax](m-n)/m-1) when the area-volume relationship of a lung unit is A(u)=K(u)V(u)m and the area-volume relationship of the lung is A(L)=V(L)n (Brancazio et al., Fed Proc. 3205, 1984), n can be written in terms of F and m as n=m(1-F)+F. In this case, F<n<1 for all values of m. This model predicts that the lung's A(L)-V(L) relationship is nearly linear during lung inflation even if open lung units expand uniformly (m=2/3).
Laboratory-animals; Laboratory-testing; Inhalation-studies; Breathing; Pulmonary-system-disorders; Lung-irritants; Models; Mathematical-models; Statistical-analysis
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The FASEB Journal
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