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Static Distribution of Lung Volumes

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Abstract

The sections in this article are:

1 Regional Static Distribution of Gas
1.1 Regional Subdivisions of Lung Volume
1.2 Relationship Between Regional and Overall Lung Volumes
2 Static Pressure‐Volume Relationship of Lungs in Situ
3 Topography of Pleural Surface Pressure in Humans
4 Mechanical Model of Static Behavior of Human Lungs
Figure 1. Figure 1.

Mean subdivisions of lung volume in 8 healthy seated men (aged 33–39 yr) at residual volume (RV) (○) and functional residual capacity (FRC) (•). Bars, 2 SE. RVr, regional residual volume; VCr, regional vital capacity; ERVr, regional expiratory reserve volume; FRCr, regional functional residual capacity; ICr, regional inspiratory capacity; TLCr, regional total lung capacity; TLCalv, alveolar volume at total lung capacity.

From Milic‐Emili
Figure 2. Figure 2.

Regional subdivisions of lung volume in subject in right and left lateral decubitus positions (top) and in subject in supine and prone positions (bottom) at RV (•) and FRC (○). Schematic position of external counters in relation to lungs is shown. Ordinates, vertical distance (D) in centimeters from lung bottom (the most dependent point of lungs). Abscissas, regional lung volume, expressed as percentage of regional total lung capacity (%TLCr).

From Kaneko et al.
Figure 3. Figure 3.

Alveolar volume expressed as percentage of its value at TLC (%TLCalv) vs. percentage of lung height in supine (top) and head‐up (bottom) dogs, rabbits, and humans at FRC.

From Milic‐Emili
Figure 4. Figure 4.

Mean relationships between regional (or alveolar) and overall lung volumes in 4 seated healthy men aged 33–39 yr. Solid lines, results from 3 lung regions (4.5, 13.8, and 22.5 cm from lung top). Dotted line, predicted relationship for lowermost lung zones. Dashed line (line of identity) indicates regional (or alveolar) percentile expansion equal to overall lung expansion.

From Sutherland, Katsura, and Milic‐Emili
Figure 5. Figure 5.

Regional volumes from Fig. vs. corresponding regional static transpulmonary pressures. Upper, middle, and lower lung regions are 4.5, 13.8, and 22.5 cm, respectively, from lung top. Po, opening airway pressure; Pc, closing airway pressure; TGVr, regional trapped‐gas volume.

From Sutherland, Katsura, and Milic‐Emili
Figure 6. Figure 6.

Alveolar air volume‐to‐surface ratio (V:S) of in situ subpleural alveoli of rabbits as function of corresponding transpulmonary pressure (P) in various sites and conditions; V:S expressed as percentage of that found on same isolated lobe at TLC. Dashed curves, relationships of V:S vs. P in isolated lobes of rabbits; dotted lines, SE. Points that do not fit statistically the relationship of V:S vs. P in isolated lobes are indicated by arrows for 2nd intercostal space of head‐up rabbits at FRC (top) and 4th intercostal space at 90% of lung height of supine eviscerated rabbits with tungsten beads in airways (bottom). Note small difference in relationships of V:S vs. P between upper and lower lobes. Palv, alveolar pressure; Pab, abdominal pressure.

From D'Angelo
Figure 7. Figure 7.

Vertical distribution of pleural surface pressure needed to account for regional distribution of gas measured at FRC in the 4 seated men of Fig. . Predictions were made with data from Figs. and , using the method of Milic‐Emili et al. . Points (○, •) indicate values obtained in 3 lung regions of Fig. .

From Milic‐Emili
Figure 8. Figure 8.

Effect of vertical gradient of pleural surface pressure on static distribution of gas within the lung during deflation. Static PV curve was taken from Fig. . Intrinsic static mechanical properties of the lungs are assumed to be uniform. Values of pleural surface pressure at apex and base obtained at 3 lung volumes (RV, FRC, and TLC) computed with the assumption that gradient does not change with lung volume. At full inspiration (C) all regions are expanded virtually uniformly despite pleural surface pressure differences down lung, but at RV (A) and FRC (B) pleural surface pressure gradient causes upper regions to be more expanded than lower regions.

From Milic‐Emili
Figure 9. Figure 9.

Effect of vertical gradient of pleural surface pressure on distribution of tidal ventilation. At the beginning of lung inflation from FRC, lower regions are operating on steeper part of compliance curve of lungs than upper regions (B). Accordingly, during slow inspiration from FRC, ventilation is greater in lower lung regions (arrows). At RV (A), pleural surface pressure at lung bottom is positive (+4.8 cmH2O) and lower airways are closed. Consequently, at the beginning of slow inspiration from RV, lower lung regions are not ventilated and lung top is preferentially ventilated (arrows).

From Milic‐Emili
Figure 10. Figure 10.

Distribution of gas in normal lung (A) and hypothetical lung in which surface tension is abolished (B). Static PV curve of lung in latter condition (B) should correspond to that obtained in saline‐filled lungs (broken line). When surface tension is abolished, lung apex is almost fully expanded at transpulmonary pressure of 8.5 cmH2O, so that during inspiration (when there is a further increase in transpulmonary pressure), ventilation at apex is virtually nil.

From Milic‐Emili et al.


Figure 1.

Mean subdivisions of lung volume in 8 healthy seated men (aged 33–39 yr) at residual volume (RV) (○) and functional residual capacity (FRC) (•). Bars, 2 SE. RVr, regional residual volume; VCr, regional vital capacity; ERVr, regional expiratory reserve volume; FRCr, regional functional residual capacity; ICr, regional inspiratory capacity; TLCr, regional total lung capacity; TLCalv, alveolar volume at total lung capacity.

From Milic‐Emili


Figure 2.

Regional subdivisions of lung volume in subject in right and left lateral decubitus positions (top) and in subject in supine and prone positions (bottom) at RV (•) and FRC (○). Schematic position of external counters in relation to lungs is shown. Ordinates, vertical distance (D) in centimeters from lung bottom (the most dependent point of lungs). Abscissas, regional lung volume, expressed as percentage of regional total lung capacity (%TLCr).

From Kaneko et al.


Figure 3.

Alveolar volume expressed as percentage of its value at TLC (%TLCalv) vs. percentage of lung height in supine (top) and head‐up (bottom) dogs, rabbits, and humans at FRC.

From Milic‐Emili


Figure 4.

Mean relationships between regional (or alveolar) and overall lung volumes in 4 seated healthy men aged 33–39 yr. Solid lines, results from 3 lung regions (4.5, 13.8, and 22.5 cm from lung top). Dotted line, predicted relationship for lowermost lung zones. Dashed line (line of identity) indicates regional (or alveolar) percentile expansion equal to overall lung expansion.

From Sutherland, Katsura, and Milic‐Emili


Figure 5.

Regional volumes from Fig. vs. corresponding regional static transpulmonary pressures. Upper, middle, and lower lung regions are 4.5, 13.8, and 22.5 cm, respectively, from lung top. Po, opening airway pressure; Pc, closing airway pressure; TGVr, regional trapped‐gas volume.

From Sutherland, Katsura, and Milic‐Emili


Figure 6.

Alveolar air volume‐to‐surface ratio (V:S) of in situ subpleural alveoli of rabbits as function of corresponding transpulmonary pressure (P) in various sites and conditions; V:S expressed as percentage of that found on same isolated lobe at TLC. Dashed curves, relationships of V:S vs. P in isolated lobes of rabbits; dotted lines, SE. Points that do not fit statistically the relationship of V:S vs. P in isolated lobes are indicated by arrows for 2nd intercostal space of head‐up rabbits at FRC (top) and 4th intercostal space at 90% of lung height of supine eviscerated rabbits with tungsten beads in airways (bottom). Note small difference in relationships of V:S vs. P between upper and lower lobes. Palv, alveolar pressure; Pab, abdominal pressure.

From D'Angelo


Figure 7.

Vertical distribution of pleural surface pressure needed to account for regional distribution of gas measured at FRC in the 4 seated men of Fig. . Predictions were made with data from Figs. and , using the method of Milic‐Emili et al. . Points (○, •) indicate values obtained in 3 lung regions of Fig. .

From Milic‐Emili


Figure 8.

Effect of vertical gradient of pleural surface pressure on static distribution of gas within the lung during deflation. Static PV curve was taken from Fig. . Intrinsic static mechanical properties of the lungs are assumed to be uniform. Values of pleural surface pressure at apex and base obtained at 3 lung volumes (RV, FRC, and TLC) computed with the assumption that gradient does not change with lung volume. At full inspiration (C) all regions are expanded virtually uniformly despite pleural surface pressure differences down lung, but at RV (A) and FRC (B) pleural surface pressure gradient causes upper regions to be more expanded than lower regions.

From Milic‐Emili


Figure 9.

Effect of vertical gradient of pleural surface pressure on distribution of tidal ventilation. At the beginning of lung inflation from FRC, lower regions are operating on steeper part of compliance curve of lungs than upper regions (B). Accordingly, during slow inspiration from FRC, ventilation is greater in lower lung regions (arrows). At RV (A), pleural surface pressure at lung bottom is positive (+4.8 cmH2O) and lower airways are closed. Consequently, at the beginning of slow inspiration from RV, lower lung regions are not ventilated and lung top is preferentially ventilated (arrows).

From Milic‐Emili


Figure 10.

Distribution of gas in normal lung (A) and hypothetical lung in which surface tension is abolished (B). Static PV curve of lung in latter condition (B) should correspond to that obtained in saline‐filled lungs (broken line). When surface tension is abolished, lung apex is almost fully expanded at transpulmonary pressure of 8.5 cmH2O, so that during inspiration (when there is a further increase in transpulmonary pressure), ventilation at apex is virtually nil.

From Milic‐Emili et al.
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J. Milic‐Emili. Static Distribution of Lung Volumes. Compr Physiol 2011, Supplement 12: Handbook of Physiology, The Respiratory System, Mechanics of Breathing: 561-574. First published in print 1986. doi: 10.1002/cphy.cp030331