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.

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.

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.

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.

Fast vs. slow exhalation before O2 inhalation alters subsequent phase III slope

1984 ◽  
Vol 56 (1) ◽  
pp. 52-56 ◽  
Author(s):  
T. S. Hurst ◽  
B. L. Graham ◽  
D. J. Cotton
Keyword(s):  
Total Lung Capacity ◽  
Normal Subjects ◽  
Phase Iii ◽  
Breath Holding ◽  
Small Airways ◽  
Residual Volume ◽  
Lung Capacity ◽  
Single Breath ◽  
Subsequent Phase ◽  
Phase Iii Slope

We studied 10 symptom-free lifetime non-smokers and 17 smokers all with normal pulmonary function studies. All subjects performed single-breath N2 washout tests by either exhaling slowly (“slow maneuver”) from end inspiration (EI) to residual volume (RV) or exhaling maximally (“fast maneuver”) from EI to RV. After either maneuver, subjects then slowly inhaled 100% O2 to total lung capacity (TLC) and without breath holding, exhaled slowly back to RV. In the nonsmokers seated upright phase III slope of single-breath N2 test (delta N2/l) was lower (P less than 0.01) for the fast vs. the slow maneuver, but this difference disappeared when the subjects repeated the maneuvers in the supine position. In contrast, delta N2/l was higher for the fast vs. the slow maneuver (P less than 0.01) in smokers seated upright. For the slow maneuver, delta N2/l was similar between smokers and nonsmokers but for the fast maneuvers delta N2/l was higher in smokers than nonsmokers (P less than 0.01). We suggest that the fast exhalation to RV decreases delta N2/l in normal subjects by decreasing apex-to-base differences in regional ratio of RV to TLC (RV/TLC) but increases delta N2/l in smokers, because regional RV/TLC increases distal to sites of small airways obstruction when the expiratory flow rate is increased.

Airway responses to inhaled histamine in asymptomatic smokers and nonsmokers

1977 ◽  
Vol 42 (4) ◽  
pp. 508-513 ◽  
Author(s):  
N. E. Brown ◽  
E. R. McFadden ◽  
R. H. Ingram
Keyword(s):  
Vital Capacity ◽  
Total Lung Capacity ◽  
Aerosol Deposition ◽  
Flow Volume ◽  
Maximal Flow ◽  
Airway Reactivity ◽  
Lung Capacity ◽  
Large Airway ◽  
Airway Response ◽  
Airway Responses

Bronchia reactivity to inhaled histamine was assessed in asymptomatic cigarette smokers and in nonsmoking atopic and nonatopic subjects. The only prechallenge between-group difference was the ratio of maximal flow on 80% helium-20% oxygen (Vmax HeO2) to maximal flow on air (Vmax air) from partial expiratory flow volume curves at 25% vital capacity (25% VC PEFV): Mean +/- SEM for smokers 1.18 /+- 0.06, atopics 1.45 +/- 0.08, nonatopics 1.51 +/- 0.03. This suggests that prior to inhalation to total lung capacity, the predominant site of resistance at flow limitation was in smaller airways of the smokers and in larger airways of both groups of nonsmokers. Following inhalation of histamine, smokers and nonatopics had similar changes in lung volumes and Vmax air which were less than in atopics. The Vmax HeO2/Vmax air ratios at 25% VC PEFV increased in smokers and decreased in nonsmokers: smokers 1.48 +/- 0.08, atopics 1.22 +/- 0.10, nontopics 1.16 +/- 0.06. This suggests a predominant large airway response in smokers and a prominent small airway response in nonsmokers. These responses may reflect differences in the predominant site of aerosol deposition rather than in airway reactivity.

Interaction of inhaled LTC4 with histamine and PGD2 on airway caliber in asthma

1989 ◽  
Vol 66 (1) ◽  
pp. 304-312 ◽  
Author(s):  
G. D. Phillips ◽  
S. T. Holgate
Keyword(s):  
Time Course ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Forced Expiratory Volume ◽  
Maximal Flow ◽  
Lung Capacity ◽  
Airway Caliber ◽  
Relevant Interaction

To investigate possible mediator interaction in asthma, the effect of inhaled leukotriene (LT) C4 on bronchoconstriction provoked by histamine and prostaglandin (PG) D2 was studied in nine asthmatic subjects. The provocation doses of histamine, PGD2, and LTC4 required to produce a 12.5% decrease in baseline forced expiratory volume in 1 s (FEV1, PD12.5) and to further this fall to 25% (PD25–12.5) were determined. On three subsequent occasions, subjects inhaled either the PD12.5 LTC4 plus vehicle or vehicle plus the PD25–12.5 of either histamine or PGD2, and FEV1 and maximal flow at 70% of vital capacity below total lung capacity after a forced partial expiratory maneuver (Vp30) followed for 45 min. From these results, predicted time-course curves for LTC4 with histamine and LTC4 with PGD2 were calculated. On two final occasions, airway caliber was followed for 45 min after inhalation of the PD12.5 LTC4 followed by the PD25–12.5 of either histamine or PGD2. During the first 9 min after LTC4-histamine and LTC4-PGD2, the decreases in airway caliber were greater than the calculated predicted response. This interaction, although small, was significant with LTC4-PGD2 for both FEV1 (P = 0.01) and Vp30 (P less than 0.05) and with LTC4-histamine for Vp30 (P less than 0.05) but not for FEV1 (P less than 0.05). We conclude that inhaled LTC4 interacts synergistically with histamine and PGD2 and that this effect, although small, may be a relevant interaction in asthma.

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.

scholarly journals Does the nitrogen single-breath washout test contribute to detecting pulmonary involvement in rheumatoid arthritis? A pilot study

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Elizabeth Jauhar Cardoso Bessa ◽  
Felipe de Miranda Carbonieri Ribeiro ◽  
Geraldo da Rocha Castelar Pinheiro ◽  
Agnaldo José Lopes
Keyword(s):  
Rheumatoid Arthritis ◽  
Pulmonary Function Tests ◽  
Airway Disease ◽  
Pulmonary Involvement ◽  
Phase Iii ◽  
Ventilation Distribution ◽  
Lung Capacity ◽  
Single Breath ◽  
Small Airway Disease ◽  
Phase Iii Slope

Abstract Objective There has been growing interest in studying small airway disease through measures of ventilation distribution, thanks to the resurgence of the nitrogen single-breath washout (N2SBW) test. Therefore, this study evaluated the contribution of the N2SBW test to the detection of pulmonary involvement in patients with rheumatoid arthritis (RA). Results Twenty-one patients with RA underwent clinical evaluation, pulmonary function tests (PFTs), including the N2SBW test, and computed tomography (CT). The main tomographic findings were air trapping and bronchiectasis (57.1% and 23.8% of cases, respectively). According to the phase III slope of the N2SBW (phase III slope), 11 and 10 patients had values < 120% predicted and > 120% predicted, respectively. Five patients with limited involvement on CT had a phase III slope > 120%. The residual volume/total lung capacity ratio was significantly different between patients with phase III slopes < 120% and > 120% (P = 0.024). Additionally, rheumatoid factor positivity was higher in patients with a phase III slope > 120% (P = 0.021). In patients with RA and airway disease on CT, the N2SBW test detects inhomogeneity in the ventilation distribution in approximately half of the cases, even in those with normal conventional PFT results.

scholarly journals Features of glossopharyngeal breathing in breath-hold divers

2006 ◽  
Vol 101 (3) ◽  
pp. 799-801 ◽  
Author(s):  
Leigh M. Seccombe ◽  
Peter G. Rogers ◽  
Nghi Mai ◽  
Chris K. Wong ◽  
Leonard Kritharides ◽  
...  
Keyword(s):  
Vital Capacity ◽  
Total Lung Capacity ◽  
Breath Hold ◽  
Lung Capacity ◽  
Diving Depth ◽  
Highly Correlated ◽  
Pressure Changes ◽  
Air Compression ◽  
The Relationship ◽  
Measured Volume

One technique employed by competitive breath-hold divers to increase diving depth is to hyperinflate the lungs with glossopharyngeal breathing (GPB). Our aim was to assess the relationship between measured volume and pressure changes due to GPB. Seven healthy male breath-hold divers, age 33 ( 8 ) [mean (SD)] years were recruited. Subjects performed baseline body plethysmography (TLCPRE). Plethysmography and mouth relaxation pressure were recorded immediately following a maximal GPB maneuver at total lung capacity (TLC) (TLCGPB) and within 5 min after the final GPB maneuver (TLCPOST). Mean TLC increased from TLCPRE to TLCGPB by 1.95 (0.66) liters and vital capacity (VC) by 1.92 (0.56) liters ( P < 0.0001), with no change in residual volume. There was an increase in TLCPOST compared with TLCPRE of 0.16 liters (0.14) ( P < 0.02). Mean mouth relaxation pressure at TLCGPB was 65 (19) cmH2O and was highly correlated with the percent increase in TLC ( R = 0.96). Breath-hold divers achieve substantial increases in measured lung volumes using GPB primarily from increasing VC. Approximately one-third of the additional air was accommodated by air compression.

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