Effect of pneumococcal lobar pneumonia on canine lung mechanics

1981 ◽  
Vol 50 (2) ◽  
pp. 283-291 ◽  
Author(s):  
S. N. Mink ◽  
R. B. Light ◽  
L. D. Wood
Keyword(s):  
Total Lung Capacity ◽  
Lower Lobe ◽  
Lung Mechanics ◽  
Pulmonary Mechanics ◽  
Tidal Breathing ◽  
Initial Value ◽  
Lobar Pneumonia ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Gas Volume

We produced left lower lobe (LLL) pneumococcal pneumonia in seven dogs and measured lung volumes and pulmonary mechanics before (day 1) and 48 h after (day 3) development of the infection. Compared with seven control dogs, total lung capacity (TLC) and functional residual capacity (FRC) decreased 550 and 140 ml, respectively, representing a 15% reduction from the initial value in both cases. Compliance measured during tidal breathing decreased by 30%, and even when corrected for the smaller FRC on day 3, specific compliance (CLsp) was reduced. At autopsy, the infected LLL had an excess weight of 89 g, and its 50% reduction in gas volume accounted for the decrease in TLC from day 1 to day 3. Compared with control dogs, there were no changes in the deflation pressure-volume curves of the noninfected lung of the pneumonia dogs. These results indicate that the reduction in TLC in bacterial lobar pneumonia was small and resulted from the reduced gas volume of the infected lobe. Assuming that the increased weight gain in the LLL represented 89 ml of exudate that filled alveoli, we propose that bacterial pneumonia reduced gas volume at FRC by filling alveoli with inflammatory exudate and further decreased TLC by preventing these alveoli from inflating. The reduced CLsp suggested nonventilation of air spaces in addition to those that were liquid filled and was consistent with nonventilation of the entire LLL.

Effect of acute alterations of blood volume on circulatory performance in humans

1981 ◽  
Vol 50 (2) ◽  
pp. 292-298 ◽  
Author(s):  
S. M. Fortney ◽  
E. R. Nadel ◽  
C. B. Wenger ◽  
J. R. Bove
Keyword(s):  
Bacterial Pneumonia ◽  
Pneumococcal Pneumonia ◽  
Total Lung Capacity ◽  
Lower Lobe ◽  
Pulmonary Mechanics ◽  
Tidal Breathing ◽  
Initial Value ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Gas Volume

We produced left lower lobe (LLL) pneumococcal pneumonia in seven dogs and measured lung volumes and pulmonary mechanics before (day 1) and 48 h after (day 3) development of the infection. Compared with seven control dogs, total lung capacity (TLC) and functional residual capacity (FRC) decreased 550 and 140 ml, respectively, representing a 15% reduction from the initial value in both cases. Compliance measured during tidal breathing decreased by 30%, and even when corrected for the smaller FRC on day 3, specific compliance (CLsp) was reduced. At autopsy, the infected LLL had an excess weight of 89 g, and its 50% reduction in gas volume accounted for the decrease in TLC from day 1 to day 3. Compared with control dogs, there were no changes in the deflation pressure-volume curves of the noninfected lung of the pneumonia dogs. These results indicate that the reduction in TLC in bacterial lobar pneumonia was small and resulted from the reduced gas volume of the infected lobe. Assuming that the increased weight gain in the LLL represented 89 ml of exudate that filled alveoli, we propose that bacterial pneumonia reduced gas volume at FRC by filling alveoli with inflammatory exudate and further decreased TLC by preventing these alveoli from inflating. The reduced CLsp suggested nonventilation of air spaces in addition to those that were liquid filled and was consistent with nonventilation of the entire LLL.

Changes in lung mechanics induced by acute isocapnic hypoxia

1977 ◽  
Vol 42 (3) ◽  
pp. 413-419 ◽  
Author(s):  
N. A. Saunders ◽  
M. F. Betts ◽  
L. D. Pengelly ◽  
A. S. Rebuck
Keyword(s):  
Total Lung Capacity ◽  
Lung Compliance ◽  
Specific Conductance ◽  
Lung Mechanics ◽  
Recoil Pressure ◽  
Lung Capacity ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Residual Capacity ◽  
Dynamic Lung Compliance

We measured lung mechanics in seven healthy males during acute isocapnic hypoxia (PAO2 = 40–50 Torr; PACO2 = 38–42 Torr). Hypoxia was accompanied by increases in total lung capacity (mean increase +/- SD; 0.40 +/- 0.24 liters; P less than 0.005) functional residual capacity (0.34 +/- 0.25 liters; P less than 0.01) and residual volume (0.56 +/- 0.44 liters; P less than 0.02) in all subjects. Specific conductance of the lung decreased during hypoxia (P less than 0.02). The static deflation pressure-volume curve of the lung was shifted upward during hypoxia in all subjects. Resting end-expiratory recoil pressure of the lung was slightly, but not significantly lower during hypoxtic expiratory lung compliance was greater during hypoxia (0.39 +/- 0.04 l/cmH2O) than control measurements (0.31 +/- 0.05 l/cmH2O; P less than 0.005). No change was noted in dynamic lung compliance. All changes in lung mechanics were reversed within three minutes of reoxygenation. We conclude that acute isocapnic hypoxia increases total lung capacity in man and suggest that this may be due to the effect of hypoxia on the airways and pulmonary circulation.

Respiratory mechanics of a small carnivore: the ferret

1982 ◽  
Vol 52 (4) ◽  
pp. 832-837 ◽  
Author(s):  
A. Vinegar ◽  
E. E. Sinnett ◽  
P. C. Kosch
Keyword(s):  
Total Lung Capacity ◽  
Lung Compliance ◽  
Pulmonary Resistance ◽  
Mustela Putorius ◽  
Tidal Breathing ◽  
Lung Capacity ◽  
Maximum Expiratory Flow ◽  
Residual Capacity ◽  
Dynamic Lung Compliance

The ferret, Mustela putorius furo, is a small relatively inexpensive carnivore with minimal housing requirements. Measurements were made from anesthetized tracheotomized supine males. Values obtained during tidal breathing for six animals (576 +/- 12 g) were as follows: tidal volume, 6.06 +/- 0.30 ml; respiratory frequency, 26.7 +/- 3.9 breaths min-1; dynamic lung compliance, 2.48 +/- 0.21 ml cmH2O-1; pulmonary resistance, 22.56 +/- 1.61 cmH2O . l–1 . s. Pressure-volume curves from nine ferrets revealed almost infinitely compliant chest walls so that lung and total respiratory system curves were essentially the same. Total lung capacity (TLC, 89 +/- 5 ml) and functional residual capacity (17.8 +/- 2.0 ml) were determined by gas freeing the lungs in vivo. The TLC of these ferrets is about the same as in 2.5-kg rabbits. Maximum expiratory flow-volume curves showed peak flows of 10.1 vital capacities (VC) . s-1 at 75% VC and flows of 8.4 and 5.4 VC . s-1 at 50 and 25% VC.

Effects of chest wall on volume and strain patterns in canine lungs

1985 ◽  
Vol 58 (4) ◽  
pp. 1055-1060
Author(s):  
W. S. Krell ◽  
J. R. Rodarte
Keyword(s):  
Chest Wall ◽  
Total Lung Capacity ◽  
Shape Change ◽  
Lower Lobe ◽  
Volume Distribution ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Anesthetized Dogs ◽  
Cartesian Coordinate ◽  
Wall Interactions

Lobar functional residual capacity-to-total lung capacity ratios (FRC/TLC) and strains in five supine anesthetized dogs were determined from volumes and side lengths of tetrahedra formed by multiple intraparenchymal markers whose positions were determined roentgenographically. Strain is related to fractional changes in length of elements in a Cartesian coordinate system and was used to describe parenchymal distortion. Volumes and strain patterns were compared in three states: intact dogs, after transection of forelimb structures to relieve traction on the chest wall, and in dogs' excised lungs. Removing traction (NT) decreased the plethysmographically determined FRC and the upper-to-lower lobe ratio (UL/LL) for FRC/TLC. The ratio in the NT state was more like the ratio in the excised lungs (UL/LL approximately equal to 1) than in the intact dog (UL/LL greater than 1). Strain patterns were similar between the intact and the NT states, indicating no lobar shape change at FRC between these two states. Strain in the excised lungs differed greatly from strains in the intact and NT states. We conclude that forelimb traction alters volume distribution between lobes and that lung-chest wall interactions are important in determining volume and strain patterns.

Topographical distribution of regional lung volume in anesthetized dogs

1983 ◽  
Vol 54 (4) ◽  
pp. 1048-1056 ◽  
Author(s):  
R. D. Hubmayr ◽  
B. J. Walters ◽  
P. A. Chevalier ◽  
J. R. Rodarte ◽  
L. E. Olson
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Important Determinant ◽  
Body Position ◽  
Lower Lobe ◽  
Lung Capacity ◽  
Topographical Distribution ◽  
Regional Lung ◽  
Residual Capacity ◽  
Anesthetized Dogs

The distribution of regional lung volume during static deflation from total lung capacity to functional residual capacity was determined from the positions of intraparenchymal metallic markers ascertained by a biplane video roentgenographic technique in supine and prone anesthetized dogs. Regional lung volumes were linearly related to overall lung volume so that regional volume could be characterized by a ventilation index (VI), which is the ventilation per alveolus relative to the ventilation of the overall lung. For the supine position, there were vertical and cephalocaudal gradients in VI in both the upper and lower lobes. Mean VI was greater in the lower lobe than in the upper lobe, but VI was less than would be predicted from extrapolation of the upper lobe relationship. For the prone position, there was no consistent gradient in VI in any direction. The magnitude of the gradients in VI and the effects of body position suggest that, in the recumbent dog, the thoracic cavity shape is a more important determinant of regional lung volume than is the effect of gravity on the lung itself.

Concurrent measurements of functional residual capacity by three methods

1962 ◽  
Vol 17 (6) ◽  
pp. 871-873 ◽  
Author(s):  
Donald F. Tierney ◽  
Jay A. Nadel
Keyword(s):  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Open Circuit ◽  
The Body ◽  
Lung Capacity ◽  
Thoracic Gas Volume ◽  
Nitrogen Dilution ◽  
Residual Capacity ◽  
The Mean ◽  
Gas Volume

We made concurrent measurements of the functional residual capacity (FRC) with the body plethysmograph (thoracic gas volume) and by 7-min and prolonged open-circuit nitrogen dilution methods (communicating gas volume). The mean difference between the 7-min communicating gas volume and the thoracic gas volume in 13 healthy subjects was only 0.13 liters. The thoracic gas volume averaged 0.99 liters larger than the communicating gas volume after 7 min of O2 breathing in 13 patients with emphysema. The communicating gas volume at 12–18 min was the same as the thoracic gas volume in 11 of 13 patients but was smaller in the other 2. When the thoracic gas volume was used to measure FRC, the total lung capacity averaged 142% of predicted normal in 13 patients with emphysema. Submitted on January 4, 1962

Effect of lung volume on pulmonary mechanics in guinea pigs

1986 ◽  
Vol 61 (1) ◽  
pp. 304-311 ◽  
Author(s):  
J. W. Watson ◽  
A. C. Jackson ◽  
J. M. Drazen
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Dynamic Compliance ◽  
Pulmonary Mechanics ◽  
Pulmonary Resistance ◽  
Lung Capacity ◽  
Mechanical Measurements ◽  
Residual Capacity ◽  
Independent Variable

The lung volume (VL) dependence of several dynamic pulmonary mechanical properties of the guinea pig lung were determined over the range of the vital capacity (10–100% VC) with the vagi intact and sectioned. We found dynamic compliance to be strongly VL dependent, decreasing as much as 85% between functional residual capacity (FRC) and total lung capacity (TLC). Below FRC, dynamic compliance either remained unchanged or decreased, depending upon the technique used in its measurement. Pulmonary resistance (RL) decreased monotonically with increasing VL, whereas pulmonary conductance was linearly related to VL. Conductance was much less sensitive to VL than compliance, increasing only 28% between FRC and TLC. The sensitivity of pulmonary conductance to VL was substantially increased by subtracting the resistance of the tracheal cannula from RL. Specific pulmonary conductance was not independent of VL but decreased approximately 45% over the range of the VC. Pulmonary inertance was found to be unaffected by VL. Extrapolation from these data indicate that small differences in FRC, which might be expected within and between studies relying on pulmonary mechanical measurements, would most strongly affect compliance estimates and only moderately alter resistance estimates. It also indicates that the use of specific pulmonary conductance does not remove VL as an independent variable.

Increased surface tension decreases pulmonary capillary volume and compliance

2002 ◽  
Vol 93 (3) ◽  
pp. 1023-1029 ◽  
Author(s):  
George P. Topulos ◽  
Richard E. Brown ◽  
James P. Butler
Keyword(s):  
Surface Tension ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Lung Capacity ◽  
Pulmonary Capillary ◽  
Before And After ◽  
Residual Capacity ◽  
Surface Tension Change ◽  
Ventilation And Perfusion

Increased surface tension is an important component of several respiratory diseases, but its effects on pulmonary capillary mechanics are incompletely understood. We measured capillary volume and specific compliance before and after increasing surface tension with nebulized siloxane in excised dog lungs. The change in surface tension was sufficient to increase lung recoil 5 cmH2O at 50% total lung capacity. Increased surface tension decreased both capillary volume and specific compliance. The changes in capillary volume and compliance were greatest at the lung volumes at which the surface tension change was greatest. Near functional residual capacity, capillary volume postsiloxane was ∼30% of control. Presiloxane capillary specific compliance was ∼7%/cmH2O near functional residual capacity and ∼2.5%/cmH2O near total lung capacity. Postsiloxane capillary-specific compliance was 3%/cmH2O, and was independent of lung volume. We conclude that in addition to their well-known effects on lung mechanics, changes in surface tension also have important effects on capillary mechanics. We speculate that these changes may in turn affect ventilation and perfusion, worsen gas exchange, and alter leukocyte sequestration.

Localized compliance of small airways in excised rat lungs using microfocal X-ray computed tomography

2004 ◽  
Vol 96 (5) ◽  
pp. 1665-1673 ◽  
Author(s):  
Toshihiro Sera ◽  
Hideki Fujioka ◽  
Hideo Yokota ◽  
Akitake Makinouchi ◽  
Ryutaro Himeno ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Small Airways ◽  
Step Method ◽  
X Ray ◽  
Lung Capacity ◽  
Residual Capacity ◽  
X Ray Computed ◽  
End Tidal

Airway compliance is a key factor in understanding lung mechanics and is used as a clinical diagnostic index. Understanding such mechanics in small airways physiologically and clinically is critical. We have determined the “morphometric change” and “localized compliance” of small airways under “near”-physiological conditions; namely, the airways were embedded in parenchyma without dehydration and fixation. Previously, we developed a two-step method to visualize small airways in detail by staining the lung tissue with a radiopaque solution and then visualizing the tissue with a cone-beam microfocal X-ray computed tomography system (Sera et al. J Biomech 36: 1587-1594, 2003). In this study, we used this technique to analyze changes in diameter and length of the same small airways (∼150 μm ID) and then evaluated the localized compliance as a function of airway generation ( Z). For smaller (<300-μm-diameter) airways, diameter was 36% larger at end-tidal inspiration and 89% larger at total lung capacity; length was 18% larger at end-tidal inspiration and 43% larger at total lung capacity than at functional residual capacity. Diameter, especially at smaller airways, did not behave linearly with V1/3 (where V is volume). With increasing lung pressure, diameter changed dramatically at a particular pressure and length changed approximately linearly during inflation and deflation. Percentage of airway volume for smaller airways did not behave linearly with that of lung volume. Smaller airways were generally more compliant than larger airways with increasing Z and exhibited hysteresis in their diameter behavior. Airways at higher Z deformed at a lower pressure than those at lower Z. These results indicated that smaller airways did not behave homogeneously.

scholarly journals Reduction of total lung capacity in obese men: comparison of total intrathoracic and gas volumes

2010 ◽  
Vol 108 (6) ◽  
pp. 1605-1612 ◽  
Author(s):  
R. A. Watson ◽  
N. B. Pride ◽  
E. Louise Thomas ◽  
J. Fitzpatrick ◽  
G. Durighel ◽  
...  
Keyword(s):  
Total Lung Capacity ◽  
Lung Capacity ◽  
Control Heart ◽  
Lung Expansion ◽  
Residual Capacity ◽  
Obese Subjects ◽  
The Difference ◽  
Magnetic Resonance Imaging Mri ◽  
And Control ◽  
Gas Volume

Restriction of total lung capacity (TLC) is found in some obese subjects, but the mechanism is unclear. Two hypotheses are as follows: 1) increased abdominal volume prevents full descent of the diaphragm; and 2) increased intrathoracic fat reduces space for full lung expansion. We have measured total intrathoracic volume at full inflation using magnetic resonance imaging (MRI) in 14 asymptomatic obese men [mean age 52 yr, body mass index (BMI) 35–45 kg/m2] and 7 control men (mean age 50 yr, BMI 22–27 kg/m2). MRI volumes were compared with gas volumes at TLC. All measurements were made with subjects supine. Obese men had smaller functional residual capacity (FRC) and FRC-to-TLC ratio than control men. There was a 12% predicted difference in mean TLC between obese (84% predicted) and control men (96% predicted). In contrast, differences in total intrathoracic volume (MRI) at full inflation were only 4% predicted TLC (obese 116% predicted TLC, control 120% predicted TLC), because mediastinal volume was larger in obese than in control [heart and major vessels (obese 1.10 liter, control 0.87 liter, P = 0.016) and intrathoracic fat (obese 0.68 liter, control 0.23 liter, P < 0.0001)]. As a consequence of increased mediastinal volume, intrathoracic volume at FRC in obese men was considerably larger than indicated by the gas volume at FRC. The difference in gas volume at TLC between the six obese men with restriction, TLC < 80% predicted (OR), and the eight obese men with TLC > 80% predicted (ON) was 26% predicted TLC. Mediastinal volume was similar in OR (1.84 liter) and ON (1.73 liter), but total intrathoracic volume was 19% predicted TLC smaller in OR than in ON. We conclude that the major factor restricting TLC in some obese men was reduced thoracic expansion at full inflation.

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