Diaphragmatic displacement measured by fluoroscopy and derived by Respitrace

1989 ◽  
Vol 67 (2) ◽  
pp. 694-698 ◽  
Author(s):  
J. A. Verschakelen ◽  
K. Deschepper ◽  
T. X. Jiang ◽  
M. Demedts
Keyword(s):  
Total Lung Capacity ◽  
Anterior Part ◽  
Posterior Part ◽  
Middle Part ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Diaphragmatic Motion

In eight healthy volunteers we simultaneously measured the axial diaphragmatic motion by fluoroscopy and the cross-sectional area changes of the rib cage (RC) and abdomen (ABD) by Respitrace (RIP) during semistatic vital capacities (VC). We found that, if the fluoroscopic axial displacement of the posterior part of the diaphragm between residual volume (RV) and total lung capacity (TLC) is considered equal to 100%, the movement of the middle part is 90%, whereas that of the anterior part is only approximately 60%; the ratio of the axial displacements to mouth volume, furthermore, decreases at high lung volumes, especially for the anterior part. The RIP signal is nearly linearly related to mouth volume, but the contribution of the RC (delta RC) progressively increases (and is approximately 80% RIP at TLC), whereas the volume contribution of the ABD (delta ABD) levels off (to 20% RIP at TLC). The diaphragmatic volume displacement calculated from the theoretical analysis described by Mead and Loring also levels off at high volumes similarly as the ABD but is approximately 50% RIP at TLC. Finally, the axial movements of the three parts of the diaphragm are linearly related to the RC and ABD cross-sectional-area changes (r 0.91–0.97) and are even significantly better correlated with the “calculated” diaphragmatic volume displacement.

Tracheal dimensions at full inflation and deflation in adolescent twins

1991 ◽  
Vol 70 (4) ◽  
pp. 1781-1786 ◽  
Author(s):  
Y. Kawakami ◽  
M. Nishimura ◽  
H. Kusaka
Keyword(s):  
Genetic Factors ◽  
Total Lung Capacity ◽  
Cross Sectional Area ◽  
Residual Volume ◽  
Sectional Area ◽  
Male Adolescent ◽  
Cross Sectional ◽  
Lung Capacity ◽  
Genetic Components ◽  
Adolescent Twins

Tracheal dimensions at total lung capacity (TLC) and residual volume (RV) were analyzed roentgenographically in 17 pairs of male adolescent twins (mean age 16.3 yr; 12 monozygotic pairs and 5 dizygotic pairs). Genetic factors dominated environmental traits in intra- as well as extrathoracic tracheal width at RV. Extrathoracic tracheal width at TLC was also governed by genetic components. Intrathoracic tracheal depth (anteroposterior diameter), length, and cross-sectional area did not seem to be genetically controlled at TLC and RV. Intrathoracic tracheal cross-sectional area increased by 14.4% and became more elliptical from RV to TLC, owing mainly to an increase in tracheal depth (16.7%). Increments from RV to TLC in tracheal depth but not width correlated with increases in lung width, depth, and height. Intrathoracic trachea was elongated 14% in association with increase in lung height from RV to TLC. At TLC, extrathoracic tracheal width was larger than intrathoracic tracheal width, but this dimension did not differ at RV. These results indicate that genetic factors influence, at least at RV, the tracheal rings more strongly than membranous parts. Intrathoracic tracheal depth but not width increases during inspiration in accordance with increase in lung volume. Extrathoracic tracheal width widens more than intrathoracic trachea from RV to TLC.

scholarly journals Functional effect of longitudinal heterogeneity in constricted airways before and after lung expansion

2012 ◽  
Vol 112 (1) ◽  
pp. 237-245 ◽  
Author(s):  
C. Wongviriyawong ◽  
R. S. Harris ◽  
H. Zheng ◽  
M. Kone ◽  
T. Winkler ◽  
...  
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Cross Sectional Area ◽  
Cylindrical Shape ◽  
Sectional Area ◽  
High Resolution Computed Tomography ◽  
Cross Sectional ◽  
Lung Capacity ◽  
Lung Expansion ◽  
Before And After

Heterogeneity in narrowing among individual airways is an important contributor to airway hyperresponsiveness. This paper investigates the contribution of longitudinal heterogeneity (the variability along the airway in cross-sectional area and shape) to airway resistance ( Raw). We analyzed chest high-resolution computed tomography scans of 8 asthmatic (AS) and 9 nonasthmatic (NA) subjects before and after methacholine (MCh) challenge, and after lung expansion to total lung capacity. In each subject, Raw was calculated for 35 defined central airways with >2 mm diameter. Ignoring the area variability and noncircular shape results in an underestimation of Raw (%Utotal) that was substantial in some airways (∼50%) but generally small (median <6%). The average contribution of the underestimation of Raw caused by longitudinal heterogeneity in the area (%Uarea) to %Utotal was 36%, while the rest was due to the noncircularity of the shape (%Ushape). After MCh challenge, %Uarea increased in AS and NA ( P < 0.05). A lung volume increase to TLC reduced %Utotal and %Uarea in both AS and NA ( P < 0.0001, except for %Utotal in AS with P < 0.01). Only in NA, %Ushape had a significant reduction after increasing lung volume to TLC ( P < 0.005). %Uarea was highly correlated, but not identical to the mean-normalized longitudinal heterogeneity in the cross-sectional area [CV2( A)] and %Ushape to the average eccentricity of the elliptical shape. This study demonstrates that Raw calculated assuming a cylindrical shape and derived from an average area along its length may, in some airways, substantially underestimate Raw. The observed changes in underestimations of Raw with the increase in lung volume to total lung capacity may be consistent with, and contribute in part to, the differences in effects of deep inhalations in airway function between AS and NA subjects.

Correlation between the Minimal Cross-Sectional Area of the Nasal Cavity and Body Surface Area: Preliminary Results in Normal Patients

2002 ◽  
Vol 16 (4) ◽  
pp. 209-213 ◽  
Author(s):  
Martin Jurlina ◽  
Ranko Mladina ◽  
Krsto Dawidowsky ◽  
Davor Ivanković ◽  
Zeljko Bumber ◽  
...  
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Anterior Part ◽  
Inferior Turbinate ◽  
Objective Evaluation ◽  
Cross Sectional Area ◽  
The Body ◽  
Sectional Area ◽  
Cross Sectional

Nasal symptoms often are inconsistent with rhinoscopic findings. However, the proper diagnosis and treatment of nasal pathology requires an objective evaluation of the narrow segments of the anterior part of the nasal cavities (minimal cross-sectional area [MCSA]). The problem is that the value of MCSA is not a unique parameter for the entire population, but rather it is a distinctive value for particular subject (or smaller groups of subjects). Consequently, there is a need for MCSA values to be standardized in a simple way that facilitates the comparison of results and the selection of our treatment regimens. We examined a group of 157 healthy subjects with normal nasal function. A statistically significant correlation was found between the body surface area and MCSA at the level of the nasal isthmus and the head of the inferior turbinate. The age of subjects was not found a statistically significant predictor for the value of MCSA. The results show that the expected value of MCSA can be calculated for every subject based on anthropometric data of height and weight.

scholarly journals Volume displaced by diaphragm motion in emphysema

2001 ◽  
Vol 91 (5) ◽  
pp. 1913-1923 ◽  
Author(s):  
Bhajan Singh ◽  
Peter R. Eastwood ◽  
Kevin E. Finucane
Keyword(s):  
Functional Residual Capacity ◽  
Vital Capacity ◽  
Cross Sectional Area ◽  
X Rays ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Lateral Chest ◽  
Diaphragm Motion

To examine the effect of hyperinflation on the volume displaced by diaphragm motion (ΔVdi), we compared nine subjects with emphysema and severe hyperinflation [residual volume (RV)/total lung capacity (TLC) 0.65 ± 0.08; mean ± SD] with 10 healthy controls. Posteroanterior and lateral chest X rays at RV, functional residual capacity, one-half inspiratory capacity, and TLC were used to measure the length of diaphragm apposed to ribcage (Lap), cross-sectional area of the pulmonary ribcage, ΔVdi, and volume beneath the lung-apposed dome of the diaphragm. Emphysema subjects, relative to controls, had increased Lap at comparable lung volumes (4.3 vs. 1.0 cm near predicted TLC, 95% confidence interval 3.4–5.2 vs. 0–2.1), pulmonary rib cage cross-sectional area (emphysema/controls 1.22 ± 0.03, P < 0.001 at functional residual capacity), and ΔVdi/ΔLap (0.25 vs. 0.14 liters/cm, P < 0.05). During a vital capacity inspiration, relative to controls, ΔVdi was normal in five (1.94 ± 0.51 liters) and decreased in four (0.51 ± 0.40 liters) emphysema subjects, and volume beneath the dome did not increase in emphysema (0 ± 0.36 vs. 0.82 ± 0.80 liters, P < 0.05). We conclude that ΔVdi can be normal in emphysema because 1) hyperinflation is shared between ribcage and diaphragm, preserving Lap, and 2) the diaphragm remains flat during inspiration.

Sex differences in growth patterns of the airways and lung parenchyma in children

1984 ◽  
Vol 56 (5) ◽  
pp. 1204-1210 ◽  
Author(s):  
R. D. Pagtakhan ◽  
J. C. Bjelland ◽  
L. I. Landau ◽  
G. Loughlin ◽  
W. Kaltenborn ◽  
...  
Keyword(s):  
Sex Differences ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Somatic Growth ◽  
Lung Parenchyma ◽  
Growth Patterns ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Capacity ◽  
Rates Of Growth

Seventeen boys and 19 girls, 8–15 yr in age, were studied to ascertain, in the two sex groups, the predictors of airway size [assessed by measurement of tracheal cross-sectional area (CSA) and maximal expiratory flows (Vmax)] and the relative rates of growth of the major divisions of the airways and lung parenchyma. In boys, total lung capacity (TLC) accounted for 77% of the variance of CSA and for 66% of the variability of Vmax. In contrast, somatic growth and maturation in girls accounted for only 45% of the variance of CSA and for 64% of the variability of Vmax; TLC was relatively unimportant. In boys, but not in girls, TLC-corrected CSA was significantly and inversely related to height and to TLC. In girls, TLC-corrected Vmax at 50 and 75% of forced vital capacity were directly related to height. These observations suggest different patterns of airway-parenchymal-somatic growth relationships in the two sexes. Furthermore, parenchymal growth appears to be the best determinant of airway growth in boys. In girls, other factors, perhaps genetic in nature, besides growth of parenchyma, may help determine airway size.

Momentum-Preserving Shaped Holes for Film Cooling

2007 ◽  
Author(s):  
T. I.-P. Shih ◽  
S. Na
Keyword(s):  
Film Cooling ◽  
Lateral Spreading ◽  
Middle Part ◽  
Cross Sectional Area ◽  
Design Concept ◽  
Sectional Area ◽  
Cross Sectional ◽  
Cooling Flow ◽  
Shaped Hole ◽  
Flow Cross

Shaped holes increase film-cooling effectiveness by using the Coanda effect to make the cooling jet stay attached to the surface and an expanding flow cross-sectional area about the hole exit to make the cooling jet spread out laterally so that more surface can be cooled. Though shaped holes increase lateral spreading, downstream penetration of the coolant is reduced because the expanding cross-sectional area decreased the momentum of the cooling flow. This paper presents a new shaped-hole design concept to enable increased lateral spreading as well as greater downstream penetration. The new shaped-hole design concept involves a W-shaped cross-sectional area in which the middle part of the W-shape protrudes and widens as the W-shaped hole widens. The goal is to keep the film-cooling flow cross-sectional area nearly constant as the shaped hole widens so that momentum can be preserved to increase both lateral and streamwise coverage of the film-cooling jet. To examine the usefulness of this design concept, CFD analyses were performed for two W-shaped holes. In one design, the W-shaped hole is similar to traditional shaped holes except that the middle part of the shaped hole is protruded to form the W shape. In the other design, the W-shaped hole continues as a shallow trench that is aligned with the main flow direction to minimize the entrainment of hot gases and to reduce pressure drag and aerodynamic interference. Computed results show the W-shaped-hole design concept to be promising in enhancing surface adiabatic effectiveness.

Effects of acute hyperinflation on chest wall mechanics in dogs

1987 ◽  
Vol 63 (4) ◽  
pp. 1493-1498 ◽  
Author(s):  
M. Decramer ◽  
T. X. Jiang ◽  
M. Demedts
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Total Lung Capacity ◽  
Emg Activity ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Capacity ◽  
Chest Wall Mechanics ◽  
Gastric Pressure ◽  
Residual Capacity

We studied chest wall mechanics at functional residual capacity (FRC) and near total lung capacity (TLC) in 14 supine anesthetized and vagotomized dogs. During breathing near TLC compared with FRC, tidal volume decreased (674 +/- 542 vs. 68 +/- 83 ml; P less than 0.025). Both inspiratory changes in gastric pressure (4.5 +/- 2.5 vs. -0.2 +/- 2.0 cmH2O; P less than 0.005) and changes in abdominal cross-sectional area (25 +/- 17 vs. -1.0 +/- 4.2%; P less than 0.001) markedly decreased; they were both often negative during inspiration near TLC. Parasternal intercostal shortening decreased (-3.0 +/- 3.7 vs. -2.0 +/- 2.7%), whereas diaphragmatic shortening decreased slightly more in both costal and crural parts (costal -8.4 +/- 2.9 vs. -4.3 +/- 4.1%, crural -22.8 +/- 13.2 vs. -10.0 +/- 7.5%; P less than 0.05). As a result, the ratio of parasternal to diaphragm shortening increased near TLC (0.176 +/- 0.135 vs. 0.396 +/- 0.340; P less than 0.05). Electromyographic (EMG) activity in the parasternals slightly decreased near TLC, whereas the EMG activity in the costal and crural parts of the diaphragm slightly increased. We conclude that 1) the mechanical outcome of diaphragmatic contraction near TLC is markedly reduced, and 2) the mechanical outcome of parasternal intercostal contraction near TLC is clearly less affected.

Maximal Expiratory Flow and Lung Volume Changes Associated with Exercise-Induced Asthma in Children and the Effect of Breathing a Low-Density Gas Mixture

1974 ◽  
Vol 46 (3) ◽  
pp. 317-329 ◽  
Author(s):  
S. R. Benatar ◽  
P. König
Keyword(s):  
Flow Rate ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Volumes ◽  
Flow Rates ◽  
Before And After ◽  
Expiratory Flow

1. Lung volumes and maximum expiratory flow volume (MEFV) curves were measured before and after exercise and after a bronchodilator in eight asthmatic children. 2. Exercise produced significant changes in all volumes and flow rates measured, but the most sensitive measurement was of flow rate at an absolute volume in the terminal portion of the forced vital capacity. Of the more simply obtained measurements maximal flow at 50% of the exhaled vital capacity was the most sensitive, but reductions in forced expiratory volume at 1 s and peak flow rate were almost as marked. 3. The marked reductions in flow rates at low lung volumes after exercise were accompanied by large increases in residual volume and a reduction in the slope of the MEFV curve. These changes suggest functional closure of some lung units and an increase in the time-constant of emptying of other units. 4. The response of flow to breathing helium—oxygen (79:21, v/v) was assessed in the dilated state (before exercise or after bronchodilator) and the constricted state (after exercise) in five of the subjects. 5. An increase in density-dependence of flow rates at all lung volumes during constriction is evidence that, despite the reduction in flow rates, convective acceleration and turbulent flow constitute a greater proportion of the total upstream resistance after exercise than before exercise. The implication is that the cross-sectional area at equal pressure points (EPP) is smaller after exercise than before exercise. This could result from either bronchoconstriction with no change in the location of EPP, or from progression of the EPP further upstream to a region where loss of airways or reduction in their diameter has rendered the total cross-sectional area considerably smaller than under normal circumstances.

Pharyngeal cross-sectional area in normal men and women

1986 ◽  
Vol 61 (3) ◽  
pp. 890-895 ◽  
Author(s):  
I. G. Brown ◽  
N. Zamel ◽  
V. Hoffstein
Keyword(s):  
Measurement Techniques ◽  
Upper Airway ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Volumes ◽  
Acoustic Reflection ◽  
Obstructive Sleep ◽  
Males And Females ◽  
Pharyngeal Area

Pharyngeal size and the dynamic behavior of the upper airway may be important factors in modulating respiratory airflow. Patients with obstructive sleep apnea are known to have reduced pharyngeal cross-sectional area. However, no systematic measurements of pharyngeal area in healthy asymptomatic subjects are available, in part due to the lack of simple, rapid, and noninvasive measurement techniques. We utilized the acoustic reflection technique to measure pharyngeal cross-sectional area in 24 healthy volunteers (14 males, 10 females). Pharyngeal area was measured during a continuous slow expiration from total lung capacity (TLC) to residual volume (RV). We compared pharyngeal cross-sectional areas in males and females at three lung volumes: TLC, 50% of vital capacity (VC), and RV. In males, pharyngeal areas (means +/- SD) were 6.4 +/- 1.3 cm2 at TLC, 5.4 +/- 0.9 cm2 at 50% VC, and 4.1 +/- 0.8 cm2 at RV. In females, pharyngeal areas were 4.8 +/- 0.6 cm2 at TLC, 4.2 +/- 0.5 cm2 at 50% VC, and 3.7 +/- 0.6 cm2 at RV. The difference in area between males and females was statistically significant at TLC and 50% VC but not at RV. However, when the pharyngeal cross-sectional area was normalized for body surface area, this difference was not significant. In males there was a negative correlation of pharyngeal area with age. We conclude that sex differences in pharyngeal area are related to body size, pharyngeal area shows a similar variation with lung volumes in males and females, and in males pharyngeal area reduces with age.

Physiology of Cough

1974 ◽  
Vol 83 (6) ◽  
pp. 761-768 ◽  
Author(s):  
P. T. MacKlem
Keyword(s):  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Lung Volumes ◽  
Flow Rates ◽  
Velocity Flow ◽  
Large Airways ◽  
Total Cross Sectional Area ◽  
Expiratory Flow ◽  
Expiratory Flow Rates

The effectiveness of cough depends upon the linear velocity of the gas in the airways. Because velocity = flow/cross-sectional area, a high flow and a small cross-section are the ideal conditions for an effective cough. Pleural pressures become positive during cough and compress the large airways producing a marked reduction in cross-sectional area. At high lung volumes, expiratory flow rates are high so that the linear velocities in the trachea are approximately one-third of the speed of sound. The velocity falls in higher bronchial generations, both because the total cross-sectional area of each generation becomes progressively larger beyond the lobar bronchi, and because at high volumes the compressed segment of the airway only extends from the lobar bronchi to the thoracic outlet of the trachea. In normal lungs cough is effective in clearing secretions from these airways only. In chronic bronchitis and emphysema, expiratory flow rates are markedly reduced. Furthermore, in some cases the large airways are more easily compressed than normal. This results in a shorter segment of the airway being compressed. For both reasons, the efficiency of cough is markedly decreased leading to retention of secretions. In cystic and varicose bronchiectasis the problem is different. There is no flow through the bronchiectatic segments because they are blind sacs, and the efficiency of cough is independent of the velocity. To empty them of their secretions is analogous to squeezing toohpaste out of a tube. This is theoretically possible at low lung volumes when the compressed segment is longer.

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