Xenon and nitrogen single-breath washout curves in patients with airway obstruction

1976 ◽  
Vol 41 (2) ◽  
pp. 185-190 ◽  
Author(s):  
M. Demedts ◽  
M. de Roo ◽  
J. Cosemans ◽  
L. Billiet ◽  
K. P. van de Woestijne
Keyword(s):  
Airway Obstruction ◽  
Chronic Obstructive Lung Disease ◽  
Chronic Obstructive ◽  
Closing Volume ◽  
Residual Volume ◽  
Time Constants ◽  
Single Breath ◽  
Volume Curve ◽  
Washout Curves ◽  
Severe Airway Obstruction

In patients with chronic obstructive lung disease, we determined single-breath N2 and 133 Xe washout curves, and regional distributions of volumes (Vr) and of 133Xe boluses inhaled at residual volume (VIRV). Patients suffering from emphysema with minimal airway obstruction demonstrated large closing volumes and apicobasal distribution gradients, apparently because of a steep pulmonary recoil pressure-volume curve. In one subject with basal small airway disease there was no vertical gradient in regional residual volume; closing volume was increased with the 133Xe technique but almost absent with the N2 technique. Patients with moderate-to-severe airway obstruction had upward-sloping alveolar plateaus without distinct phase IV, and small apicobasal differences in Vr and VIRV. The latter resulted probably from increased regional differences in time constants counteracting the influence of gravity. Finally, patients with severe airway obstruction and basal emphysema demonstrated a rising N2 but a descending 133Xe plateau; the gradient for VIRV was normal, and reversed for Vr. This pattern was attributed to nongravitational differences in time constants causing a first in-first out distribution.

scholarly journals Acute effects of long-acting bronchodilators on small airways detected in COPD patients by single-breath N2 test and lung P-V curve

2017 ◽  
Vol 123 (5) ◽  
pp. 1266-1275 ◽  
Author(s):  
Matteo Pecchiari ◽  
Pierachille Santus ◽  
Dejan Radovanovic ◽  
Edgardo DʼAngelo
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Phase Iii ◽  
Chronic Obstructive ◽  
Closing Volume ◽  
Small Airways ◽  
Acute Effects ◽  
Obstructive Pulmonary Disease ◽  
Single Breath ◽  
Volume Curve

Small airways represent the key factor of chronic obstructive pulmonary disease (COPD) pathophysiology. The effect of different classes of bronchodilators on small airways is still poorly understood and difficult to assess. Hence the acute effects of tiotropium (18 µg) and indacaterol (150 µg) on closing volume (CV) and ventilation inhomogeneity were investigated and compared in 51 stable patients (aged 70 ± 7 yr, mean ± SD; 82% men) with moderate to very severe COPD. Patients underwent body plethysmography, arterial blood gas analysis, tidal expiratory flow limitation (EFL), dyspnea assessment, and simultaneous recording of single-breath N2 test and transpulmonary pressure-volume curve (PL-V), before and 1 h after drug administration. The effects produced by indacaterol on each variable did not differ from those caused by tiotropium, independent of the severity of disease, assessed according to the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) scale and the presence of EFL. Bronchodilators significantly decreased the slope of phase III and CV (−5 ± 4 and −2.5 ± 2.1%, respectively, both P < 0.001), with an increase in both slope and height of phase IV and of the anatomical dead space. Arterial oxygen pressure and saturation significantly improved (3 ± 3 mmHg and 2 ± 2%, respectively, both P < 0.001); their changes negatively correlated with those of phase III slope ( r = −0.659 and r = −0.454, respectively, both P < 0.01). The vital capacity (VC) increased substantially, but the PL-V/VC curve above CV was unaffected. In conclusion, bronchodilators reduce the heterogeneity of peripheral airway mechanical properties and the extent of their closure, with minor effects on critical closing pressure. This should lessen the risk of small-airway damage and positively affect gas exchange. NEW & NOTEWORTHY This is the first study investigating in stable chronic obstructive pulmonary disease patients the acute effects of two long-acting bronchodilators, a β-agonist and a muscarinic antagonist, on peripheral airways using simultaneous lung pressure-volume curve and single-breath N2 test. By lessening airway mechanical property heterogeneity, both drugs similarly reduced ventilation inhomogeneity and extent of small-airway closure, as indicated by the decrease of phase III slope, increased oxygen saturation, and fall of closing volume, often below expiratory reserve volume.

Influence of collateral ventilation on single-breath washout curves

1988 ◽  
Vol 64 (1) ◽  
pp. 429-434 ◽  
Author(s):  
S. Tomioka ◽  
S. Kubo ◽  
H. J. Guy ◽  
G. K. Prisk
Keyword(s):  
Transpulmonary Pressure ◽  
Phase Iii ◽  
Closing Volume ◽  
Single Breath ◽  
Age Related ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Washout Curves ◽  
Collateral Ventilation ◽  
Phase Iv

To examine the relationship between airway closure and collateral ventilation, Ar bolus single-breath washout tests were performed in the supine position in 10 mature dogs (animals with a well-developed collateral ventilation). Transpulmonary pressure was measured simultaneously to obtain the volume above residual volume of the inflection point in the pressure-volume curve (VIP). In pigs, closing volume (CV/VC%, mean 27.4%, where VC is vital capacity) equaled the volume of inflection (VIP/VC%, mean 35.1%) when the dead space (0.07 liter) was accounted for, indicating simultaneous onset. In dogs, closing volume (CV/VC%, mean 48.1%) was greater than the volume of inflection (VIP/VC%, mean 27%). Furthermore, as closing volume increased, so did the volume exhaled between closing volume and the volume of inflection [(CV-VIP)/VC%]. These increases were strongly age related, with the oldest dogs showing the greatest differences between closing volume and volume of inflection. These results support the previous suggestion that this difference is a measure of the degree of collateral ventilation. We defined a concavity index (CI) of phase IV by measuring the ratio of the end-to-mid phase IV height above extrapolated phase III (no concavity implies CI = 2). Whereas pigs had a low CI (mean 3.3), dogs had a high CI (mean 10.6). In dogs, the CI correlated well with closing volume (CV/VC%) and the volume exhaled between closing volume and volume of inflection [(CV-VIP)/VC%]. Again, this relationship was strongly dependent on age, suggesting that the CI is also a valid indication of the degree of collateral ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Inflection point on transpulmonary pressure-volume curves and closing volume

1975 ◽  
Vol 38 (2) ◽  
pp. 228-235 ◽  
Author(s):  
M. Demedts ◽  
J. Clement ◽  
D. C. Stanescu ◽  
K. P. van de Woestijne
Keyword(s):  
Inflection Point ◽  
Vital Capacity ◽  
Transpulmonary Pressure ◽  
Bronchial Obstruction ◽  
Closing Volume ◽  
Lung Volumes ◽  
Nitrogen Washout ◽  
Single Breath ◽  
Space Effect ◽  
Washout Curves

In 20 healthy subjects and 18 patients with bronchial obstruction, closing volume (CV) on single-breath nitrogen washout curves and inflection point (IP) on transpulmonary pressure-volume curves were recorded simultaneously during slow expiratory vital capacity maneuvers. IP and CV did not occur at identical lung volumes, IP being systematically larger than CV for small CV values. This discrepancy could not be attributed to an esophageal or mediastinal artifact. It is suggested that, though CV and IP both express “airway closure,” their sensitivity to closure may differ: CV underestimates closure because of a dead space effect; the latter may vary individually. On the other hand, IP may not reflect the true beginning of closure, particularly when it occurs at higher lung volumes.

Physical Signs in Childhood Asthma

PEDIATRICS ◽  
1976 ◽  
Vol 58 (4) ◽  
pp. 537-541
Author(s):  
J. O. O. Commey ◽  
Henry Levison
Keyword(s):  
Pulmonary Function ◽  
Airway Obstruction ◽  
Pulmonary Function Tests ◽  
Severe Disease ◽  
Airway Disease ◽  
Chronic Obstructive ◽  
Scalene Muscle ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Severe Airway Obstruction

In 62 children with bronchial asthma, the presence of subjective dyspnea and wheeze, and some physical signs commonly associated with chronic obstructive airway disease in older patients, were compared with results of routine pulmonary function tests. Overall, airway resistance and the relationships of residual volume and functional residual capacity to total lung capacity were increased and other measurements of pulmonary function were moderately decreased. The time-honored subjective dyspnea, wheeze, rhonchi, and prolonged expiration were least useful as indices of severity of disease. Most of the patients, particularly those in whom laboratory testing revealed marked impairment, had notable rhonchi, prolonged expiration, scalene muscle and sternocleidomastoid contraction, and supraclavicular indrawing. Only sternocleidomastoid contraction and supraclavicular indrawing clearly correlated with the severity of airway obstruction. A call is made for a search for these useful signs, whose presence may be the only clue to moderately severe disease; however, their absence does not guarantee absence of severe airway obstruction.

Aerosol penetrance: a sensitive index of peripheral airways obstruction

1976 ◽  
Vol 40 (3) ◽  
pp. 468-471 ◽  
Author(s):  
M. B. Dolovich ◽  
J. Sanchis ◽  
C. Rossman ◽  
M. T. Newhouse
Keyword(s):  
Chronic Obstructive Lung Disease ◽  
Outer Zone ◽  
Normal Subjects ◽  
Airway Disease ◽  
Chronic Obstructive ◽  
Closing Volume ◽  
Small Airways ◽  
Peripheral Airways ◽  
Sensitive Index ◽  
Airways Obstruction

Early injury of the small airways has been demonstrated in asymptomatic smokers. Ventilatory tests including the maximum midexpiratory flow rate and closing volume have been useful in clinical detection of small airways disease in symptomatic subjects. In the present study, airway “obstruction” was assessed aerodynamically by gamma camera measurements of chest radioactivity following the inhalation of 131I-labeled aerosol (aerodynamic mass median diameter 3 mum). Studies were performed in normal subjects, asymptomatic smokers, and patients with chronic obstructive lung disease. An aerosol penetrance index (AeP) was devised from determinations which involved 1) an analysis of central (inner zone) and peripheral (outer zone) deposition of aerosol in the lung and 2) a ratio of initial counts to 24-h counts in the periphery (outer zone) of the lung. AeP values were 41.5 +/- 11.5 for the normal group, 20.9 +/- 7.6 for the smoker group, and 10.6 +/- 5.2 for the subjects with chronic obstructive airway disease. AeP was significantly reduced in the smokers indicating that the AeP is a sensitive index of early peripheral airways obstruction.

Gravitational independence of single-breath washout tests in recumbent dogs

1988 ◽  
Vol 64 (2) ◽  
pp. 642-648 ◽  
Author(s):  
S. Tomioka ◽  
S. Kubo ◽  
H. J. Guy ◽  
G. K. Prisk
Keyword(s):  
Prone Position ◽  
Regional Distribution ◽  
Transpulmonary Pressure ◽  
Phase Iii ◽  
Closing Volume ◽  
Body Rotation ◽  
Single Breath ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Phase Iv

To examine the mechanisms of lung filling and emptying, Ar-bolus and N2 single-breath washout tests were conducted in 10 anesthetized dogs (prone and supine) and in three of those dogs with body rotation. Transpulmonary pressure was measured simultaneously, allowing identification of the lung volume above residual volume at which there was an inflection point in the pressure-volume curve (VIP). Although phase IV for Ar was upward, phase IV for N2 was small and variable, especially in the prone position. No significant prone to supine differences in closing capacity for Ar were seen, indicating that airway closure was generated at the same lung volumes. The maximum deflections of phase IV for Ar and N2 from extrapolated phase III slopes were smaller in the prone position, suggesting more uniform tracer gas concentrations across the lungs. VIP was smaller than the closing volume for Ar, which is consistent with the effects of well-developed collateral ventilation in dogs. Body rotation tests in three dogs did not generally cause an inversion of phase III or IV. We conclude that in recumbent dogs regional distribution of ventilation is not primarily determined by the effect of gravity, but by lung, thorax, and mediastinum interactions and/or differences in regional mechanical properties of the lungs.

scholarly journals Exercise-induced airway obstruction in relation to chronic obstructive lung disease

Thorax ◽  
1974 ◽  
Vol 29 (1) ◽  
pp. 16-20 ◽  
Author(s):  
F. Gimeno ◽  
W. Chr. Berg ◽  
E. J. Steenhuis ◽  
K. de Vries ◽  
R. Peset ◽  
...  
Keyword(s):  
Lung Disease ◽  
Airway Obstruction ◽  
Obstructive Lung Disease ◽  
Chronic Obstructive Lung Disease ◽  
Chronic Obstructive ◽  
Exercise Induced

scholarly journals Ability of single-breath nitrogen closing volume to detect early airway obstruction.

Thorax ◽  
1975 ◽  
Vol 30 (2) ◽  
pp. 220-224 ◽  
Author(s):  
A Funahashi ◽  
G N Melville ◽  
L H Hamilton
Keyword(s):  
Airway Obstruction ◽  
Closing Volume ◽  
Single Breath

scholarly journals Predictors of cardiovascular disease in asthma and chronic obstructive pulmonary disease

2013 ◽  
Vol 8 ◽  
Author(s):  
Michela Bellocchia ◽  
Monica Masoero ◽  
Antonio Ciuffreda ◽  
Silvia Croce ◽  
Arianna Vaudano ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Pulmonary Hypertension ◽  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Airway Obstruction ◽  
Older Age ◽  
Ischemic Heart ◽  
Chronic Obstructive ◽  
Copd Patients ◽  
Severe Airway Obstruction

Background: Cardiovascular disease (CVD) is a common comorbidity in patients with chronic airway obstruction, and is associated with systemic inflammation and airway obstruction. The aim of this study was to evaluate the predictors of CVD in two different conditions causing chronic airway obstruction, asthma and COPD. Methods: Lung function tests, clinical and echocardiographic data were assessed in 229 consecutive patients, 100 with asthma and 129 with COPD. CVD was classified into: pressure overload (PO) and volume overload (VO). Sub-analysis of patients with ischemic heart disease (IHD) and pulmonary hypertension (PH) was also performed. Results: CVD was found in 185 patients (81%: 51% COPD and 30% asthmatics) and consisted of PO in 42% and of VO in 38% patients. COPD patients, as compared to asthmatics, had older age, more severe airway obstruction, higher prevalence of males, of smokers, and of CVD (91% vs 68%), either PO (46% vs 38%) or VO (45% vs 30%). CVD was associated with older age and more severe airway obstruction both in asthma and COPD. In the overall patients the predictive factors of CVD were age, COPD, and male sex; those of PO were COPD, BMI, VC, FEV1 and MEF50 and those of VO were age, VC and MEF50. In asthma, the predictors of CVD were VC, FEV1, FEV1 /VC%, and PaO2, those of PO were VC, FEV1 and FEV1 /VC%, while for VO there was no predictor. In COPD the predictors of CVD were age, GOLD class and sex, those of VO age, VC and MEF50, and that of PO was BMI. Sub-analysis showed that IHD was predicted by COPD, age, BMI and FEV1, while PH (found only in 25 COPD patients), was predicted by VO (present in 80% of the patients) and FEV1. In subjects aged 65 years or more the prevalence of CVD, PO and VO was similar in asthmatic and COPD patients, but COPD patients had higher prevalence of males, smokers, IHD, PH, lower FEV1 and higher CRP. Conclusions: The results of this study indicate that cardiovascular diseases are frequent in patients with chronic obstructive disorders, particularly in COPD patients. The strongest predictors of CVD are age and airway obstruction. COPD patients have higher prevalence of ischemic heart disease and pulmonary hypertension. In the elderly the prevalence of PO and VO in asthma and COPD patients is similar.

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