scholarly journals Attenuation of induced bronchoconstriction in healthy subjects: effects of breathing depth

2005 ◽  
Vol 98 (3) ◽  
pp. 817-821 ◽  
Author(s):  
Francesco G. Salerno ◽  
Riccardo Pellegrino ◽  
Gianluca Trocchio ◽  
Antonio Spanevello ◽  
Vito Brusasco ◽  
...  

The effects of breathing depth in attenuating induced bronchoconstriction were studied in 12 healthy subjects. On four separate, randomized occasions, the depth of a series of five breaths taken soon (∼1 min) after methacholine (MCh) inhalation was varied from spontaneous tidal volume to lung volumes terminating at ∼80, ∼90, and 100% of total lung capacity (TLC). Partial forced expiratory flow at 40% of control forced vital capacity (V̇part) and residual volume (RV) were measured at control and again at 2, 7, and 11 min after MCh. The decrease in V̇part and the increase in RV were significantly less when the depth of the five-breath series was progressively increased ( P < 0.001), with a linear relationship. The attenuating effects of deep breaths of any amplitude were significantly greater on RV than V̇part ( P < 0.01) and lasted as long as 11 min, despite a slight decrease with time when the end-inspiratory lung volume was 100% of TLC. In conclusion, in healthy subjects exposed to MCh, a series of breaths of different depth up to TLC caused a progressive and sustained attenuation of bronchoconstriction. The effects of the depth of the five-breath series were more evident on the RV than on V̇part, likely due to the different mechanisms that regulate airway closure and expiratory flow limitation.

1994 ◽  
Vol 77 (2) ◽  
pp. 963-973 ◽  
Author(s):  
D. D. Marciniuk ◽  
G. Sridhar ◽  
R. E. Clemens ◽  
T. A. Zintel ◽  
C. G. Gallagher

Lung volumes were measured at rest and during exercise by an open-circuit N2-washout technique in patients with interstitial lung disease (ILD). Exercise tidal flow-volume (F-V) curves were also compared with maximal F-V curves to investigate whether these patients demonstrated flow limitation. Seven patients underwent 4 min of constant work rate bicycle ergometer exercise at 40, 70, and 90% of their previously determined maximal work rates. End-expiratory lung volume and total lung capacity were measured at rest and near the end of each period of exercise. There was no significant change in end-expiratory lung volume or total lung capacity when resting measurements were compared with measurements at 40, 70, and 90% work rates. During exercise, expiratory flow limitation was evident in four patients who reported stopping exercise because of dyspnea. In the remaining patients who discontinued exercise because of leg fatigue, no flow limitation was evident. In all patients, the mean ratio of maximal minute ventilation to maximal ventilatory capacity (calculated from maximal F-V curves) was 67%. We conclude that lung volumes during exercise do not significantly differ from those at rest in this population and that patients with ILD may demonstrate expiratory flow limitation during exercise. Furthermore, because most patients with ILD are not breathing near their maximal ventilatory capacity at the end of exercise, we suggest that respiratory mechanics are not the primary cause of their exercise limitation.


PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 181-193
Author(s):  
C. D. Cook ◽  
P. J. Helliesen ◽  
L. Kulczycki ◽  
H. Barrie ◽  
L. Friedlander ◽  
...  

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.


1962 ◽  
Vol 17 (5) ◽  
pp. 783-786 ◽  
Author(s):  
John S. Hanson ◽  
Burton S. Tabakin ◽  
Edgar J. Caldwell

Variations in size of the various lung volumes due to changes in body position and as a consequence of treadmill exercise were studied in five normal males. Assumption of the upright posture was associated with highly significant increases in total lung capacity, vital capacity, expiratory reserve volume, and residual volume as compared to resting supine values. Level walking was associated with a decrease of expiratory reserve volume, but a further expansion of residual volume. Vital capacity decreased slightly, but total lung capacity increased by virtue of the proportionately large residual volume increases. Elevation of the treadmill to 4° resulted in slight decreases in all lung volumes, total lung capacity evidencing a barely significant decline. Positional changes in ventilation are described, and on the basis of the “lung clearance index” an increased efficiency of ventilation is seen in the upright posture. Factors possibly operative in these alterations are discussed. Submitted on February 21, 1962


1987 ◽  
Vol 62 (1) ◽  
pp. 39-46 ◽  
Author(s):  
T. L. Clanton ◽  
G. F. Dixon ◽  
J. Drake ◽  
J. E. Gadek

Lung volumes and inspiratory muscle (IM) function tests were measured in 16 competitive female swimmers (age 19 +/- 1 yr) before and after 12 wk of swim training. Eight underwent additional IM training; the remaining eight were controls. Vital capacity (VC) increased 0.25 +/- 0.25 liters (P less than 0.01), functional residual capacity (FRC) increased 0.39 +/- 0.29 liters (P less than 0.001), and total lung capacity (TLC) increased 0.35 +/- 0.47 (P less than 0.025) in swimmers, irrespective of IM training. Residual volume (RV) did not change. Maximum inspiratory mouth pressure (PImax) measured at FRC changed -43 +/- 18 cmH2O (P less than 0.005) in swimmers undergoing IM conditioning and -29 +/- 25 (P less than 0.05) in controls. The time that 65% of prestudy PImax could be endured increased in IM trainers (P less than 0.001) and controls (P less than 0.05). All results were compared with similar IM training in normal females (age 21.1 +/- 0.8 yr) in which significant increases in PImax and endurance were observed in IM trainers only with no changes in VC, FRC, or TLC (Clanton et al., Chest 87: 62–66, 1985). We conclude that 1) swim training in mature females increases VC, TLC, and FRC with no effect on RV, and 2) swim training increases IM strength and endurance measured near FRC.


1960 ◽  
Vol 15 (1) ◽  
pp. 40-42 ◽  
Author(s):  
Stanley S. Heller ◽  
William R. Hicks ◽  
Walter S. Root

Lung volume determinations (tidal volume, inspiratory capacity, inspiratory reserve volume, expiratory reserve volume, vital capacity, maximum breathing capacity, functional residual capacity, residual volume, and total lung capacity) were carried out on 16 professional singers and 21 subjects who had had no professional vocal training. No differences were found between the two groups of subjects, whether recumbent or standing, which could not be explained upon the basis of age, size, or errors involved in making the measurements. Submitted on March 24, 1959


1986 ◽  
Vol 60 (6) ◽  
pp. 1834-1838 ◽  
Author(s):  
R. B. Filuk ◽  
N. R. Anthonisen

Nine normal young men inhaled boluses of He at the onset of slow vital capacity (VC) inspirations. During the subsequent VC expirations, we measured expired flow, volume, and He concentrations. Expirations consisted of full or partial maximum expiratory flow-volume (MEFV) maneuvers. Full maneuvers were forced expirations from total lung capacity (TLC). Partial maneuvers were accomplished by expiring slowly from TLC to 70, 60, 50, and 40% VC and then initiating forced expiration. Expired He concentrations from full and partial maneuvers were compared with each other and with those resulting from slow expirations. At comparable volumes less than 50% VC, flow during partial and full MEFV maneuvers did not differ. Expired He concentrations were higher during partial maneuvers than during full ones; at the onset of partial maneuvers upper zone emptying predominated, whereas this was not the case at the same lung volumes during maneuvers initiated at TLC. We observed substantial differences in regional emptying sequence that did not influence maximum expiratory flow.


1999 ◽  
Vol 87 (5) ◽  
pp. 1973-1980 ◽  
Author(s):  
Nikolai Aljuri ◽  
Lutz Freitag ◽  
José G. Venegas

Flow limitation during forced exhalation and gas trapping during high-frequency ventilation are affected by upstream viscous losses and by the relationship between transmural pressure (Ptm) and cross-sectional area ( A tr) of the airways, i.e., tube law (TL). Our objective was to test the validity of a simple lumped-parameter model of expiratory flow limitation, including the measured TL, static pressure recovery, and upstream viscous losses. To accomplish this objective, we assessed the TLs of various excised animal tracheae in controlled conditions of quasi-static (no flow) and steady forced expiratory flow. A tr was measured from digitized images of inner tracheal walls delineated by transillumination at an axial location defining the minimal area during forced expiratory flow. Tracheal TLs followed closely the exponential form proposed by Shapiro (A. H. Shapiro. J. Biomech. Eng. 99: 126–147, 1977) for elastic tubes: Ptm = K p[( A tr/ A tr0)− n − 1], where A tr0 is A tr at Ptm = 0 and K p is a parametric factor related to the stiffness of the tube wall. Using these TLs, we found that the simple model of expiratory flow limitation described well the experimental data. Independent of upstream resistance, all tracheae with an exponent n < 2 experienced flow limitation, whereas a trachea with n > 2 did not. Upstream viscous losses, as expected, reduced maximal expiratory flow. The TL measured under steady-flow conditions was stiffer than that measured under expiratory no-flow conditions, only if a significant static pressure recovery from the choke point to atmosphere was assumed in the measurement.


1993 ◽  
Vol 36 (3) ◽  
pp. 516-520 ◽  
Author(s):  
Jeannette D. Hoit ◽  
Nancy Pearl Solomon ◽  
Thomas J. Hixon

This investigation was designed to test the hypothesis that voice onset time (VOT) varies as a function of lung volume. Recordings were made of five men as they repeated a phrase containing stressed /pi/ syllables, beginning at total lung capacity and ending at residual volume. VOT was found to be longer at high lung volumes and shorter at low lung volumes in most cases. This finding points out the need to take lung volume into account when using VOT as an index of laryngeal behavior in both healthy individuals and those with speech disorders.


1997 ◽  
Vol 83 (3) ◽  
pp. 936-947 ◽  
Author(s):  
Bengt Kayser ◽  
Pawel Sliwinski ◽  
Sheng Yan ◽  
Mirek Tobiasz ◽  
Peter T. Macklem

Kayser, Bengt, Pawel Sliwinski, Sheng Yan, Mirek Tobiasz, and Peter T. Macklem. Respiratory effort sensation during exercise with induced expiratory-flow limitation in healthy humans. J. Appl. Physiol. 83(3): 936–947, 1997.—Nine healthy subjects (age 31 ± 4 yr) exercised with and without expiratory-flow limitation (maximal flow ∼1 l/s). We monitored flow, end-tidal [Formula: see text], esophageal (Pes) and gastric pressures, changes in end-expiratory lung volume, and perception (sensation) of difficulty in breathing. Subjects cycled at increasing intensity (+25 W/30 s) until symptom limitation. During the flow-limited run, exercise performance was limited in all subjects by maximum sensation. Sensation was equally determined by inspiratory and expiratory pressure changes. In both runs, 90% of the variance in sensation could be explained by the Pes swings (difference between peak inspiratory and peak expiratory Pes). End-tidal[Formula: see text] did not explain any variance in sensation in the control run and added only 3% to the explained variance in the flow-limited run. We conclude that in healthy subjects, during normal as well as expiratory flow-limited exercise, the pleural pressure generation of the expiratory muscles is equally related to the perception of difficulty in breathing as that of the inspiratory muscles.


1981 ◽  
Vol 51 (2) ◽  
pp. 313-316 ◽  
Author(s):  
F. Ruff ◽  
R. R. Martin ◽  
J. Milic-Emili

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.


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