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Number of open lung units during an inflation-deflation cycle based on differences between small loop and quasi-static compliance of PL-VL curves.

Authors
Frazer-DG; Reynolds-JS; Burdette-N; McKinney-W; Lindsley-W
Source
FASEB J 2007 Apr; 21(6)(Suppl):A827
NIOSHTIC No.
20031948
Abstract
In excised rat lungs, the compliance of small sinusoidal perturbations superimposed on a quasi-static PL-VL curve differs from the quasi-static compliance in several regions along the curve. Assuming the lung is composed of individual lung units which can be in either an "open" or "closed" state, lung volume (VL) can be represented by the product of the average volume of an open lung unit (VU) and the number of open units (No). The quasi-static compliance of the lung (CTOT=dVL/dPL) can then be written as: dVL/dPL = No dVU/dPL + VU dNo/dPL. In this expression No dVU/dPL represents loop compliance (CL), and VU dNo/dPL represents a compliance resulting from the opening and closing of lung units. The anatomical structure of a lung unit has not yet been identified. By comparing CTOT with CL, a system of differential equations can be evaluated to predict how normalized values (indicated by *) of VU* and No* are related to VL* during a complete inflation-deflation cycle ([No*]dVU*/dPL= CL* and [VU*]dNo*/dPL= CTOT* - CL*. Results show that VU* and No* approximately follow the relationships VU* = VL*0.3 and No* = VL*0.7 during both lung inflation and deflation between transpulmonary pressures of +30 and 0 cm H2O.
Keywords
Cell-function; Mathematical-models; Statistical-analysis; Lung-function; Lung-cells; Pulmonary-function; Pulmonary-system; Biological-function; Biological-monitoring; Cell-biology; Cell-alteration; Cell-metabolism
Contact
Health Effects Laboratory Division, CDC National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV, 26505
CODEN
FAJOEC
Publication Date
20070401
Document Type
Abstract; Conference/Symposia Proceedings
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
6
ISSN
0892-6638
NIOSH Division
HELD
Priority Area
Healthcare and Social Assistance
Source Name
The FASEB Journal
State
WV
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