Surfactant release in excised rat lung is stimulated by air inflation

1981 ◽  
Vol 51 (4) ◽  
pp. 905-910 ◽  
Author(s):  
J. N. Hildebran ◽  
J. Goerke ◽  
J. A. Clements
Keyword(s):  
Total Lung Capacity ◽  
Lung Surfactant ◽  
Lung Lavage ◽  
Rat Lung ◽  
Alveolar Space ◽  
Lung Capacity ◽  
Rat Lungs ◽  
Basal Release

Because increased ventilation has been associated with an acceleration of lung surfactant turnover, we investigated the effect of fluid and air inflations on the release of surfactant into the air spaces. We found that excised rat lungs, initially lavaged three times at 23 degrees C, release approximately 40–90 micrograms of phospholipid/g wet lung wt into the air spaces in response to a further infusion of fluid into the airway equal to total lung capacity. A single air inflation to the same volume, followed by degassing and lavage, contributes approximately 230 micrograms to the yield of phospholipid. We estimated basal release of phospholipid as 112 micrograms wet lung wt-1 . h-1, which is far less than the 2,050 micrograms -1 . h-1 retrieved during a series of air and fluid inflations. The above findings are consistent with the hypothesis that air inflation to total lung capacity is a major physiological stimulus to release of lung surfactant into the alveolar space. The lung lavage process itself also causes the release of surfactant.

scholarly journals Alveolar epithelial surface area-volume relationship in isolated rat lungs

1999 ◽  
Vol 86 (6) ◽  
pp. 2026-2033 ◽  
Author(s):  
Daniel J. Tschumperlin ◽  
Susan S. Margulies
Keyword(s):  
Basement Membrane ◽  
Surface Area ◽  
Total Lung Capacity ◽  
Membrane Surface ◽  
Epithelial Surface ◽  
Alveolar Epithelial ◽  
Lung Capacity ◽  
Epithelial Basement Membrane ◽  
Rat Lungs ◽  
Epithelial Basement

In vitro studies of the alveolar epithelial response to deformation require knowledge of the in situ mechanical environment of these cells. Because of the presence of tissue folding and crumpling, previous measurements of the alveolar surface area available for gas exchange are not equivalent to the epithelial surface area. To identify epithelial deformations in uniformly inflated lungs representative of the in vivo condition, we studied isolated Sprague-Dawley rat lungs ( n = 31) fixed by perfusion with glutaraldehyde on deflation after cycling three times at high lung volume (10–25 cmH2O). The epithelial basement membrane in 45 electron micrographs (×12,000)/rat was traced, digitally scanned, and analyzed. Epithelial basement membrane surface area (EBMSA) was computed from a morphometric relationship. EBMSA was found to increase 5, 16, 12, and 40% relative to EBMSA at 24% total lung capacity at lung volumes of 42, 60, 82, and 100% total lung capacity, respectively. The increases in EBMSA suggest that epithelial cells undergo significant deformations with large inflations and that alveolar basement membrane deformation may contribute to lung recoil at high lung pressures.

Lung lavage using a single-lumen endotracheal tube

1975 ◽  
Vol 38 (5) ◽  
pp. 922-926 ◽  
Author(s):  
B. A. Muggenburg ◽  
J. L. Mauderly
Keyword(s):  
Pulmonary Function ◽  
Endotracheal Tube ◽  
Breathing Pattern ◽  
Total Lung Capacity ◽  
Pulmonary Function Tests ◽  
Lung Lavage ◽  
Dependent Lung ◽  
Lung Capacity ◽  
Single Lumen ◽  
Cardiopulmonary System

The physiological response of the cardiopulmonary system of the dog during and after bronchopulmonary lavage via a single-lumen endotracheal tube was evaluated. The five Beagle dogs used in the study were prepared for lavage by anesthetization, vascular cannulation, intubation with a single-lumen endotracheal tube, and hyperventilation with 100 percent oxygen. Lavage was performed by placing a dog in lateral recumbency, slowly introducing saline to a volume approximating the total lung capacity of the dependent lung, and then draining the lung immediately by gravity. After brief ventilation the lavage sequence was repeated until five washes using a total of 2,000 ml were completed. The dog was then turned to the opposite side and the washing sequence repeated on the other lung. The heart rate slowed but pulmonary and systemic arterial mean pressures did not change. The PAo2 decreased from 317 to 107 mmHg during the procedure, but Paco2 did not increase and remained below 40 mmHg. Pulmonary function tests at 24 h after lavage revealed only a few mild changes in breathing pattern and gas exchange. At 168 h after lavage pulmonary function values did not differ significantly from prelavage values.

Airway-parenchymal interdependence after airway contraction in rat lung explants

1998 ◽  
Vol 85 (1) ◽  
pp. 231-237 ◽  
Author(s):  
Andy Adler ◽  
Elizabeth A. Cowley ◽  
Jason H. T. Bates ◽  
David H. Eidelman
Keyword(s):  
Elastic Modulus ◽  
Total Lung Capacity ◽  
Radial Distance ◽  
Radial Component ◽  
Micromechanical Modeling ◽  
Rat Lung ◽  
Lung Capacity ◽  
Airway Constriction ◽  
Before And After ◽  
Fractional Reduction

The constriction of pulmonary airways is limited by the tethering effect exerted by parenchymal attachments. To characterize this tethering effect at the scale of intraparenchymal airways, we studied the pattern of parenchymal distortion due to bronchoconstriction in a rat lung explant system. First, we measured the elastic modulus under tension for 2% (wt/vol) agarose alone (37.6 ± 1.5 kPa) and for agarose-filled lung (5.7 ± 1.3 kPa). The latter is similar to the elastic modulus of air-filled lung at total lung capacity (4.5–6 kPa) (S. J. Lai-Fook, T. A. Wilson, R. E. Hyatt, and J. R. Rodarte. J. Appl. Physiol. 40: 508–513, 1976), suggesting that explants can be used as a model of lung tissue distortion. Subsequently, confocal microscopic images of fluorescently labeled 0.5-mm-thick explants prepared from agarose-filled rat lungs inflated to total lung capacity (48 ml/kg) were acquired. Images were taken before and after airway constriction was induced by direct application of 10 mM methacholine, and the pattern of parenchymal distortion was measured from the displacement of tissue landmarks identified in each image for 14 explants. The magnitude of the radial component of tissue displacement was calculated as a function of distance from the airway wall and characterized by a parameter, b, describing the rate at which tissue movement decreased with radial distance. The parameter b was 0.994 ± 0.19 (SE), which is close to the prediction of b = 1 of micromechanical modeling (T. A. Wilson. J. Appl. Physiol. 33: 472–478, 1972). There was significant variability in b, however, which was correlated with the fractional reduction in airway diameter ( r = 0.496). Additionally, parenchymal distortion showed significant torsion with respect to the radial direction. This torsion was similar in concentric zones around the airway, suggesting that it originates from inhomogeneity in the parenchyma rather than inhomogeneous airway constriction. Our results demonstrate the significance of the nonlinear mechanical properties of alveolar walls and the anisotropy of the parenchyma in determining the nature of airway-parenchymal interdependence.

Ventilation Heterogeneity in Asthma and COPD: The Value of the Poorly Communicating Fraction as the Ratio of Total Lung Capacity to Alveolar Volume

Respiration ◽  
2021 ◽  
pp. 1-7
Author(s):  
Roberta Pisi ◽  
Marina Aiello ◽  
Luigino Calzetta ◽  
Annalisa Frizzelli ◽  
Veronica Alfieri ◽  
...  
Keyword(s):  
Total Lung Capacity ◽  
Airflow Obstruction ◽  
Diffusing Capacity ◽  
Body Plethysmography ◽  
Alveolar Volume ◽  
Asthmatic Patients ◽  
Lung Capacity ◽  
Copd Patients ◽  
Ventilation Heterogeneity ◽  
Patient Groups

<b><i>Background:</i></b> The ventilation heterogeneity (VH) is reliably assessed by the multiple-breath nitrogen washout (MBNW), which provides indices of conductive (<i>S</i><sub>cond</sub>) and acinar (<i>S</i><sub>acin</sub>) VH as well as the lung clearance index (LCI), an index of global VH. VH can be alternatively measured by the poorly communicating fraction (PCF), that is, the ratio of total lung capacity by body plethysmography to alveolar volume from the single-breath lung diffusing capacity measurement. <b><i>Objectives:</i></b> Our objective was to assess VH by PCF and MBNW in patients with asthma and with COPD and to compare PCF and MBNW parameters in both patient groups. <b><i>Method:</i></b> We studied 35 asthmatic patients and 45 patients with COPD. Each patient performed spirometry, body plethysmography, diffusing capacity, and MBNW test. <b><i>Results:</i></b> Compared to COPD patients, asthmatics showed a significantly lesser degree of airflow obstruction and lung hyperinflation. In asthmatic patients, both PCF and LCI and <i>S</i><sub>acin</sub> values were significantly lower than the corresponding ones of COPD patients. In addition, in both patient groups, PCF showed a positive correlation with LCI (<i>p</i> &#x3c; 0.05) and <i>S</i><sub>acin</sub> (<i>p</i> &#x3c; 0.05), but not with <i>S</i><sub>cond</sub>. Lastly, COPD patients with PCF &#x3e;30% were highly likely to have a value ≥2 of the mMRC dyspnea scale. <b><i>Conclusions:</i></b> These results showed that PCF, a readily measure derived from routine pulmonary function testing, can provide a comprehensive measure of both global and acinar VH in asthma and in COPD patients and can be considered as a comparable tool to the well-established MBNW technique.

Radiographie and Plethysmographie Determination of Total Lung Capacity

Radiology ◽  
1966 ◽  
Vol 86 (1) ◽  
pp. 7-30 ◽  
Author(s):  
Herbert M. Loyd ◽  
S. Timothy String ◽  
Arthur B. DuBois
Keyword(s):  
Total Lung Capacity ◽  
Lung Capacity

STUDIES OF RESPIRATORY PHYSIOLOGY IN CHILDREN

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Compliance ◽  
Respiratory Physiology ◽  
Residual Volume ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Residual Capacity

Tidal volume, respiratory rate and lung volumes have been measured in 64 patients with cystic fibrosis of the pancreas while lung compliance and resistance were measured in 42 of these. Serial studies of lung volumes were done in 43. Tidal volume was reduced and the respiratory rate increased only in the most severely ill patients. Excluding the three patients with lobectomies, residual volume and functional residual capacity were found to be significantly increased in 46 and 21%, respectively. These changes correlated well with the roentgenographic evaluation of emphysema. Vital capacity was significantly reduced in 34% while total lung capacity was, on the average, relatively unchanged. Seventy per cent of the 61 patients had a signficantly elevated RV/TLC ratio. Lung compliance was significantly reduced in only the most severely ill patients but resistance was significantly increased in 35% of the patients studied. The serial studies of lung volumes showed no consistent trends among the groups of patients in the period between studies. However, 10% of the surviving patients showed evidence of significant improvement while 15% deteriorated. [See Fig. 8. in Source Pdf.] Although there were individual discrepancies, there was a definite correlation between the clinical evaluation and tests of respiratory function, especially the changes in residual volume, the vital capacity, RV/ TLC ratio and the lung compliance and resistance.

scholarly journals Patterns of regional lung physiology in cystic fibrosis using ventilation magnetic resonance imaging and multiple-breath washout

2018 ◽  
Vol 52 (5) ◽  
pp. 1800821 ◽  
Author(s):  
Laurie J. Smith ◽  
Guilhem J. Collier ◽  
Helen Marshall ◽  
Paul J.C. Hughes ◽  
Alberto M. Biancardi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cystic Fibrosis ◽  
Total Lung Capacity ◽  
Resonance Imaging ◽  
Ventilation Distribution ◽  
Lung Clearance ◽  
Lung Capacity ◽  
Lung Clearance Index ◽  
Ventilation Heterogeneity ◽  
Multiple Breath Washout

Hyperpolarised helium-3 (3He) ventilation magnetic resonance imaging (MRI) and multiple-breath washout (MBW) are sensitive methods for detecting lung disease in cystic fibrosis (CF). We aimed to explore their relationship across a broad range of CF disease severity and patient age, as well as assess the effect of inhaled lung volume on ventilation distribution.32 children and adults with CF underwent MBW and 3He-MRI at a lung volume of end-inspiratory tidal volume (EIVT). In addition, 28 patients performed 3He-MRI at total lung capacity. 3He-MRI scans were quantitatively analysed for ventilation defect percentage (VDP), ventilation heterogeneity index (VHI) and the number and size of individual contiguous ventilation defects. From MBW, the lung clearance index, convection-dependent ventilation heterogeneity (Scond) and convection–diffusion-dependent ventilation heterogeneity (Sacin) were calculated.VDP and VHI at EIVT strongly correlated with lung clearance index (r=0.89 and r=0.88, respectively), Sacin (r=0.84 and r=0.82, respectively) and forced expiratory volume in 1 s (FEV1) (r=−0.79 and r=−0.78, respectively). Two distinct 3He-MRI patterns were highlighted: patients with abnormal FEV1 had significantly (p<0.001) larger, but fewer, contiguous defects than those with normal FEV1, who tended to have numerous small volume defects. These two MRI patterns were delineated by a VDP of ∼10%. At total lung capacity, when compared to EIVT, VDP and VHI reduced in all subjects (p<0.001), demonstrating improved ventilation distribution and regions of volume-reversible and nonreversible ventilation abnormalities.

Rib cage and abdominal restrictions have different effects on lung mechanics

1980 ◽  
Vol 49 (6) ◽  
pp. 946-952 ◽  
Author(s):  
C. A. Bradley ◽  
N. R. Anthonisen
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Lung Mechanics ◽  
Elastic Recoil ◽  
Rib Cage ◽  
Lung Capacity ◽  
Single Breath ◽  
Restrictive Procedures ◽  
Maximum Expiratory Flow ◽  
Per Se

The effects of a variety of restrictive procedures on lung mechanics were studied in eight healthy subjects. Rib cage restriction decreased total lung capacity (TLC) by 43% and significantly increased elastic recoil and maximum expiratory flow (MEF). Subsequent immersion of four subjects with rib cage restriction resulted in no further change in either parameter; shifts of blood volume did not reverse recoil changes during rib cage restriction. Abdominal restriction decreased TLC by 40% and increased MEF and elastic recoil, but recoil was increased significantly less than was the case with rib cage restriction. Further, at a given recoil pressure, MEF was less during rib cage restriction than during either abdominal restriction or no restriction. Measurements of the unevenness of inspired gas distribution by the single-breath nitrogen technique showed increased unevenness during rib cage restriction, which was significantly greater than that during abdominal restriction. We conclude that lung volume restriction induces changes in lung function, but the nature of these changes depends on how the restriction is applied and therefore cannot be ascribed to low lung volume breathing per se.

Transmission of pressure within the abdomen

1996 ◽  
Vol 81 (3) ◽  
pp. 1111-1114 ◽  
Author(s):  
G. E. Tzelepis ◽  
L. Nasiff ◽  
F. D. McCool ◽  
J. Hammond
Keyword(s):  
Fluid Mechanics ◽  
Sigmoid Colon ◽  
Total Lung Capacity ◽  
Hydraulic Model ◽  
Abdominal Pressure ◽  
Lung Capacity ◽  
Pressure Changes

The extent to which transmission of pressure within the abdomen is accomplished in accordance with the laws of fluid mechanics, i.e., homogeneous transmission to all portions of the abdomen, is controversial. To examine the cranial-to-caudal as well as side-to-side transmission of pressure within the abdomen in humans, we measured intra-abdominal pressure at four sites in five subjects undergoing colonoscopy. Liquid-filled catheters were inserted into the colon, and intracolonic pressure was measured in the rectum and in transverse, descending, and sigmoid colon. Differences in intracolonic pressure were recorded during breaths to total lung capacity and brief expulsive maneuvers. Measurements were taken in the supine, right lateral, and seated position. Comparison of pressure swings at all sites showed that the pressure changes were nearly equal during both inspiratory and expulsive maneuvers. The changes in pressure were uniform in the cephalocaudal axis as from side to side. We conclude that transmission of abdominal pressure in humans is nearly homogeneous. Our findings provide support for the hydraulic model of abdominal mechanics.

Abdominal distension alters regional pleural pressures and chest wall mechanics in pigs in vivo

1991 ◽  
Vol 70 (6) ◽  
pp. 2611-2618 ◽  
Author(s):  
T. Mutoh ◽  
W. J. Lamm ◽  
L. J. Embree ◽  
J. Hildebrandt ◽  
R. K. Albert
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Abdominal Cavity ◽  
Abdominal Distension ◽  
Abdominal Pressure ◽  
Lung Capacity ◽  
Lung Expansion ◽  
Residual Capacity

Abdominal distension (AD) occurs in pregnancy and is also commonly seen in patients with ascites from various causes. Because the abdomen forms part of the "chest wall," the purpose of this study was to clarify the effects of AD on ventilatory mechanics. Airway pressure, four (vertical) regional pleural pressures, and abdominal pressure were measured in five anesthetized, paralyzed, and ventilated upright pigs. The effects of AD on the lung and chest wall were studied by inflating a liquid-filled balloon placed in the abdominal cavity. Respiratory system, chest wall, and lung pressure-volume (PV) relationships were measured on deflation from total lung capacity to residual volume, as well as in the tidal breathing range, before and 15 min after abdominal pressure was raised. Increasing abdominal pressure from 3 to 15 cmH2O decreased total lung capacity and functional residual capacity by approximately 40% and shifted the respiratory system and chest wall PV curves downward and to the right. Much smaller downward shifts in lung deflation curves were seen, with no change in the transdiaphragmatic PV relationship. All regional pleural pressures increased (became less negative) and, in the dependent region, approached 0 cmH2O at functional residual capacity. Tidal compliances of the respiratory system, chest wall, and lung were decreased 43, 42, and 48%, respectively. AD markedly alters respiratory system mechanics primarily by "stiffening" the diaphragm/abdomen part of the chest wall and secondarily by restricting lung expansion, thus shifting the lung PV curve as seen after chest strapping. The less negative pleural pressures in the dependent lung regions suggest that nonuniformities of ventilation could also be accentuated and gas exchange impaired by AD.

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