Effect of previous volume history on airway closure

1983 ◽  
Vol 55 (2) ◽  
pp. 294-299
Author(s):  
H. W. Greville ◽  
L. J. Slykerman ◽  
P. A. Easton ◽  
N. R. Anthonisen
Keyword(s):  
Regional Distribution ◽  
Lung Parenchyma ◽  
Breath Hold ◽  
Closing Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Lung Capacity ◽  
Normal Humans ◽  
Volume History ◽  
Previous Volume

We studied the effect of volume history on airway closure in six healthy males ranging from 32 to 67 yr of age. The method used was to compare the regional distribution of 133Xe boluses distributed according to N2O uptake during open-glottis breath-hold maneuvers with the regional distribution of boluses of intravenously injected 133Xe. Measurements were made at two lung volumes, one close to residual volume (RV) and the other just below closing volume. The required volume was reached either by expiring from total lung capacity or by inspiring from RV. Although there was considerable airway closure in the basal regions of the lungs at both lung volumes studied, the degree of airway closure was not dependent on the previous volume history. We conclude that the airways concerned with closure have a volume-pressure hysteresis similar to that of the lung parenchyma. Furthermore in normal humans the volume-pressure hysteresis of the lung is not secondary to airway closure.

Airway closure and closing volume

1979 ◽  
Vol 46 (1) ◽  
pp. 24-30 ◽  
Author(s):  
L. Forkert ◽  
S. Dhingra ◽  
N. R. Anthonisen
Keyword(s):  
Blood Flow ◽  
Lung Volume ◽  
Regional Perfusion ◽  
Phase Iii ◽  
Breath Hold ◽  
Closing Volume ◽  
Residual Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Phase Iv

Using boluses of radioactive Xe we compared regional N2O uptake with regional perfusion distribution during open glottis breath hold in five seated men. Measurements were made near residual volume, at closing volume (CV), above CV and when possible, between CV and residual volume (RV). At low lung volumes basal N2O uptake was small whereas basal blood flow was not. This discrepancy was interpreted as evidence of airway closure and was quantitated. All subjects showed extensive basal closure near RV. At closing volume four of five subjects demonstrated closure and some closure was evident in these subjects at volumes in excess of CV. The increase in airway closure with decreasing lung volume was much greater below CV than above it. Conventional CV tracings were obtained using helium boluses; the height of phase IV was positively correlated with the change in airway closure between CV and RV as assessed by the N2O technique. The slope of phase III did not correlate with the amount of airway closure measured at CV. We concluded that the conventionally measured CV is not the volume at which airway closure begins but that the onset of phase IV reflects an increase in basal airway closure and the height of phase IV reflects the amount of basal closure between CV and RV.

Effect of volume history on distribution of inspired gas in asthmatics

1987 ◽  
Vol 62 (3) ◽  
pp. 1179-1185 ◽  
Author(s):  
R. B. Filuk ◽  
N. R. Anthonisen
Keyword(s):  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Parenchyma ◽  
Phase Iii ◽  
Ventilation Distribution ◽  
Lung Capacity ◽  
Beta Agonists ◽  
Airway Tone ◽  
Washout Curves ◽  
Volume History

Twelve stable adult asthmatics slowly inhaled boluses of He at 20, 40, or 60% vital capacity (VC); these volumes were achieved either by expiring from total lung capacity (TLC) or by inspiring from residual volume (RV). Inspirations were continued to TLC and then were followed by slow expirations to RV while expired He was measured as a function of expired volume. At 20% VC slopes of alveolar plateaus (phase III) were positive, at 40% VC they were flat, and at 60% VC they were negative; at 20 and 60% VC the slopes were steeper than those in normals. When boluses were administered at 40 and 60% VC, He washout curves were independent of lung volume history. However at 20% VC the slope of phase III was significantly less positive when boluses were given after inspiration from RV than after expiration from TLC. In eight subjects, who were given inhaled beta-agonists, slopes of all He washouts decreased and became independent of volume history at 20% VC. We conclude that in asthmatics at low lung volumes the airways that determine ventilation distribution behave as though they have less hysteresis than the lung parenchyma probably due to increased airway tone.

Effect of chest strapping on regional lung function

1975 ◽  
Vol 39 (5) ◽  
pp. 707-713 ◽  
Author(s):  
G. W. Sybrecht ◽  
L. Garrett ◽  
N. R. Anthonisen
Keyword(s):  
Lung Function ◽  
Regional Distribution ◽  
Lung Mechanics ◽  
Airway Closure ◽  
Elastic Recoil ◽  
Lung Volumes ◽  
Regional Lung Function ◽  
Regional Lung ◽  
Maximum Expiratory Flow ◽  
Expiratory Flow

We studied lung mechanics and regional lung function in five young men during restrictive chest strapping. The effects on lung mechanics were similar to those noted by others in that lung elastic recoil increased as did maximum expiratory flow at low lung volumes. Chest strapping reduced the maximum expiratory flow observed at a given elastic recoil pressure. Breathing helium increased maximum expiratory flow less when subjects were strapped than when they were not. These findings indicated that strapping decreased the caliber of airways upstream from the equal pressure point. Regional lung volumes from apex to base were measured with xenon 133 while subjects were seated. The distribution of regional volumes was measured at RV, and at volumes equal to strapped FRC and strapped TLC; no change due to chest strapping was observed. Similarly, the regional distribution of 133Xe boluses inhaled at RV and strapped TLC was unaffected by chest strapping. Closing capacity decreased with chest strapping. We concluded that airway closure decreased during chest strapping and that airway closure was not the cause of the observed increase in elastic recoil of the lung. The combination of decreased slope of the static pressure-volume curve and unchanged regional volumes suggested that strapping increased the apex-to-base pleural pressure gradient.

Previous volume history of the lung and regional distribution of residual volume

1981 ◽  
Vol 51 (2) ◽  
pp. 313-316 ◽  
Author(s):  
F. Ruff ◽  
R. R. Martin ◽  
J. Milic-Emili
Keyword(s):  
Vital Capacity ◽  
Total Lung Capacity ◽  
Regional Distribution ◽  
Breath Hold ◽  
Small Airways ◽  
Residual Volume ◽  
Lung Capacity ◽  
Lower Lung ◽  
History Of ◽  
Collateral Ventilation

By use of 133Xe, the regional distribution of residual volume (RV) was measured in six seated healthy men, following a fast vital capacity (VC) expiration a) without and b) with a breath hold at residual volume of approximately 30 s and c) following a slow (greater than 30 s) VC expiration from total lung capacity (TLC) without a breath hold at RV. After the breath hold at RV, regional RV/TLC in the lower lung zones decreased significantly compared wih results obtained with fast expiratory VC and no breath hold at RV. At lung top the opposite was true. The distribution of regional RV/TLC was the same following the slow VC expiration with no breath hold at RV as with the fast expiration with the breath hold at RV. The different regional distribution of RV in b and c relative to a was probably due mainly to collateral ventilation, i.e., during the breath hold at RV and the slow expiration some of the gas that was trapped in the dependent lung zones behind closed airways escaped into the upper regions of the lung where the small airways had remained patent, leading to increased expansion of upper alveoli.

Respiratory system reactance is an independent determinant of asthma control

2013 ◽  
Vol 115 (9) ◽  
pp. 1360-1369 ◽  
Author(s):  
Vanessa J. Kelly ◽  
Scott A. Sands ◽  
R. Scott Harris ◽  
Jose G. Venegas ◽  
Nathan J. Brown ◽  
...  
Keyword(s):  
Asthma Control ◽  
Respiratory System ◽  
Lung Volume ◽  
Strong Predictor ◽  
Closing Volume ◽  
Forced Oscillation Technique ◽  
Airway Closure ◽  
Lung Volumes ◽  
Ventilation Heterogeneity ◽  
Peripheral Airway

The mechanisms underlying not well-controlled (NWC) asthma remain poorly understood, but accumulating evidence points to peripheral airway dysfunction as a key contributor. The present study tests whether our recently described respiratory system reactance (Xrs) assessment of peripheral airway dysfunction reveals insight into poor asthma control. The aim of this study was to investigate the contribution of Xrs to asthma control. In 22 subjects with asthma, we measured Xrs (forced oscillation technique), spirometry, lung volumes, and ventilation heterogeneity (inert-gas washout), before and after bronchodilator administration. The relationship between Xrs and lung volume during a deflation maneuver yielded two parameters: the volume at which Xrs abruptly decreased (closing volume) and Xrs at this volume (Xrscrit). Lowered (more negative) Xrscrit reflects reduced apparent lung compliance at high lung volumes due, for example, to heterogeneous airway narrowing and unresolved airway closure or near closure above the critical lung volume. Asthma control was assessed via the 6-point Asthma Control Questionnaire (ACQ6). NWC asthma was defined as ACQ6 > 1.0. In 10 NWC and 12 well-controlled subjects, ACQ6 was strongly associated with postbronchodilator (post-BD) Xrscrit ( R2 = 0.43, P < 0.001), independent of all measured variables, and was a strong predictor of NWC asthma (receiver operator characteristic area = 0.94, P < 0.001). By contrast, Xrs measures at lower lung volumes were not associated with ACQ6. Xrscrit itself was significantly associated with measures of gas trapping and ventilation heterogeneity, thus confirming the link between Xrs and airway closure and heterogeneity. Residual airway dysfunction at high lung volumes assessed via Xrscrit is an independent contributor to asthma control.

Contribution of airway closure to chronic postbronchiolitis airway dysfunction in rats

2004 ◽  
Vol 96 (3) ◽  
pp. 904-910 ◽  
Author(s):  
Ronald L. Sorkness ◽  
Amjad Tuffaha
Keyword(s):  
Sendai Virus ◽  
Airflow Obstruction ◽  
Forced Expiratory Volume ◽  
Brown Norway ◽  
Early Age ◽  
Airway Closure ◽  
Pulmonary Resistance ◽  
Pressure Monitor ◽  
Lung Volumes ◽  
Lung Capacity

Genetically susceptible Brown Norway rats develop a chronic asthmalike syndrome after recovering from viral bronchiolitis at an early age. We hypothesized that airway closure is an important mechanism of airflow obstruction in postbronchiolitis rats. Rats were studied 8–12 wk after inoculation with Sendai virus or sterile vehicle at 3–4 wk of age. Under light pentobarbital anesthesia, rats were instrumented with an orotracheal catheter and an esophageal pressure monitor and placed in a total body plethysmograph. Lung volumes and forced-expiratory maneuvers were measured using the Boyle's law method and software-controlled valving of positive and negative pressures to elicit lung inflations and rapid deflations; pulmonary resistance was measured during spontaneous tidal breathing; and quasi-static pressure-volume curves were obtained with passive inflations and deflations in fully anesthetized, paralyzed rats. Compared with controls, the postbronchiolitis rats had elevated pulmonary resistance and reduced forced-expiratory volume in 0.2 s. Most of the reduced forced-expiratory volume in 0.2 s was associated with reduced forced vital capacity, indicating premature airway closure as a prominent mechanism. The reduced airflow in postbronchiolitis rats was highly dependent on lung volume, being nearly normal at 70% lung capacity, but sevenfold less than normal at 30% lung capacity. Increased respiratory system hysteresis between functional reserve capacity and total lung capacity was evidence for increased airway closure at normal end-expiratory lung volumes in postbronchiolitis rats. We conclude that airway instability and closure is a prominent mechanism of the chronic airway dysfunction in rats that have recovered from viral bronchiolitis at an early age.

Lung recoil and gas trapping during oxygen breathing at low lung volumes

1977 ◽  
Vol 43 (1) ◽  
pp. 138-143 ◽  
Author(s):  
J. R. Rodarte ◽  
L. W. Burgher ◽  
R. E. Hyatt ◽  
K. Rehder
Keyword(s):  
Inspiratory Pressure ◽  
Closing Volume ◽  
Airway Closure ◽  
Lung Volumes ◽  
Recoil Pressure ◽  
Normal Volunteers ◽  
Oxygen Breathing ◽  
Gas Trapping ◽  
Low Volume

If airways are closed at lung volumes less than the closing volume (CV), there should be correlations among 1) the volume of trapped N2 (VTN) during N2-washout performed below CV, 2) the increase in static lung recoil pressure (delta P) while breathing below CV after denitrogenation compared with breathing air (due to absorption atelectasis distal to closed airways), and 3) the CV. Static inspiratory pressure-volume (PV) curves and CV were measured in 18 seated normal volunteers (ages 24–48 yr). Subjects then breathed air for 30 s and O2 for 2.5 min at RV + 0.6 liter (LVB-air), and an inspiratory PV curve and VTN were determined. While still breathing O2, the subjects repeated the 3 min of low-volume breathing (LVB-O2). There was a significant (P less than 0.001) delta P with LVB but no difference between delta P (LVB-air) and delta P (LVB-O2). CV was not related to VTN or to either delta P. VTN was not related to delta P (LVB-O2)--delta P (LVB-air) nor to delta P (LVB-air), but was related to delta P (LVB-O2). Evidence of airway closure could not be demonstrated in all subjects by LVB and when present showed no correlation with CV.

Previous volume history of the lung and regional distribution of gas.

1968 ◽  
Vol 25 (5) ◽  
pp. 566-574 ◽  
Author(s):  
P W Sutherland ◽  
T Katsura ◽  
J Milic-Emili
Keyword(s):  
Regional Distribution ◽  
History Of ◽  
Volume History ◽  
Previous Volume

Heterogeneous airway tone in asthmatic subjects

1992 ◽  
Vol 73 (6) ◽  
pp. 2328-2332 ◽  
Author(s):  
G. Julia-Serda ◽  
N. A. Molfino ◽  
K. R. Chapman ◽  
P. A. McClean ◽  
N. Zamel ◽  
...  
Keyword(s):  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Lung Parenchyma ◽  
Flow Volume ◽  
Lung Capacity ◽  
Group I ◽  
Expiratory Flow ◽  
Airway Tone ◽  
Volume History

We examined the effect of volume history on the dynamic relationship between airways and lung parenchyma (relative hysteresis) in 20 asthmatic subjects. The acoustic reflection technique was employed to evaluate changes in airway cross-sectional areas during a slow continuous expiration from total lung capacity to residual volume and inspiration back to total lung capacity. Lung volume was measured continuously during this quasi-static maneuver. We studied three anatomic airway segments: extra- and intrathoracic tracheal and main bronchial segments. Plots of airway area vs. lung volume were obtained for each segment to assess the relative magnitude and direction of the airway and parenchymal hysteresis. We also performed maximal expiratory flow-volume and partial expiratory flow-volume curves and calculated the ratio of maximal to partial flow rates (M/P) at 30% of the vital capacity. We found that 10 subjects (group I) showed a significant predominance of airway over parenchymal hysteresis (P < 0.005) at the extra- and intrathoracic tracheal and main bronchial segments; these subjects had high M/P ratios [1.53 +/- 0.27 (SD)]. The other 10 subjects (group II) showed similar airway and parenchymal hysteresis for all three segments and significantly lower M/P ratios (1.16 +/- 0.20, P < 0.01). We conclude that the effect of volume history on the relative hysteresis of airway and lung parenchyma and M/P ratio at 30% of vital capacity in nonprovoked asthmatic subjects is variable. We suggest that our findings may result from heterogeneous airway tone in asthmatic subjects.

Transpulmonary pressures and lung mechanics with glossopharyngeal insufflation and exsufflation beyond normal lung volumes in competitive breath-hold divers

2007 ◽  
Vol 102 (3) ◽  
pp. 841-846 ◽  
Author(s):  
Stephen H. Loring ◽  
Carl R. O'Donnell ◽  
James P. Butler ◽  
Peter Lindholm ◽  
Francine Jacobson ◽  
...  
Keyword(s):  
Lung Mechanics ◽  
Normal Lung ◽  
Breath Hold ◽  
Lung Volumes ◽  
Pressure Equalization ◽  
Lung Capacity ◽  
Middle Ear Pressure ◽  
Helium Dilution ◽  
Predicted Values ◽  
Gas Volume

Throughout life, most mammals breathe between maximal and minimal lung volumes determined by respiratory mechanics and muscle strength. In contrast, competitive breath-hold divers exceed these limits when they employ glossopharyngeal insufflation (GI) before a dive to increase lung gas volume (providing additional oxygen and intrapulmonary gas to prevent dangerous chest compression at depths recently greater than 100 m) and glossopharyngeal exsufflation (GE) during descent to draw air from compressed lungs into the pharynx for middle ear pressure equalization. To explore the mechanical effects of these maneuvers on the respiratory system, we measured lung volumes by helium dilution with spirometry and computed tomography and estimated transpulmonary pressures using an esophageal balloon after GI and GE in four competitive breath-hold divers. Maximal lung volume was increased after GI by 0.13–2.84 liters, resulting in volumes 1.5–7.9 SD above predicted values. The amount of gas in the lungs after GI increased by 0.59–4.16 liters, largely due to elevated intrapulmonary pressures of 52–109 cmH2O. The transpulmonary pressures increased after GI to values ranging from 43 to 80 cmH2O, 1.6–2.9 times the expected values at total lung capacity. After GE, lung volumes were reduced by 0.09–0.44 liters, and the corresponding transpulmonary pressures decreased to −15 to −31 cmH2O, suggesting closure of intrapulmonary airways. We conclude that the lungs of some healthy individuals are able to withstand repeated inflation to transpulmonary pressures far greater than those to which they would normally be exposed.

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