lung zone


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lung zone

A hypothetical region of the lung defined by the relationship between the degree of alveolar ventilation and pulmonary blood flow (perfusion). Three lung zones have been identified: I, ventilation exceeds perfusion; II, ventilation and perfusion are equal; and III, perfusion exceeds ventilation. Zone I is found in the upper lung field, where gravity impedes perfusion, and zone III in the inferior portion of the lung, where gravity assists perfusion.
See also: zone
References in periodicals archive ?
15) The consolidation is typically predominant in the middle and lower lung zones with a subpleural or peribronchovascular distribution.
8 Table 2: Mean lung attenuation measured in inspiration and correlation of FEV1 and FEF 25-75% with air trapping in different lung zones.
0 Lung zones involved >2 zones 68 (69) 58 (63) Extent of the disease Bilateral 64 (65) 47 (51) Initial 1+ 28 (29) 43 (47) smear 2+ 49 (50) 38 (41) grading 3+ 21 (21) 11 (12) Initial [less than or 4 (4) 12 (13) equal to] 1+ culture 2+ 19 (19) 23 (25) grading 3+ 75 (77) 57 (62) Figures in parentheses are percentages HIV-TB (n=88) All (n=278) Sex Males 72 (82) 216 (78) Age (yr) Median 34.
In healthy subjects at the peak of hypoxia, the pulmonary flow in the upper lung zones increased by 24% and in lower lung zones, in contrary, reduced approximately to the same value.
A chest radiograph taken at a local hospital revealed category 2/3 profusion of small, nodular opacities in the middle and lower lung zones, consistent with silicosis.
Unilateral opacity occurred predominantly in the upper lung zones.
A chest X-ray showed heterogeneous right-sided opacity in the middle and lower lung zones.
Specifically, there were no pulmonary micronodules that are typical of GLILD, and there was no pleuroparenchymal thickening in the upper lung zones, which is typical of PPFE.
The overall mean percentage (peak radiographic opacification) of lung parenchymal involvement was calculated by averaging the percentage involvement of the six lung zones.