Pulmonary function in bronchial asthma.

Meisner, Peter; Hugh‐Jones, P.

doi:10.1136/bmj.1.5590.470

Cited by 42 publications

(19 citation statements)

References 18 publications

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“…In our sample, we did not find any relationship between the degree of airway obstruction (FEV 1 ) and gas exchange impairment (PaO 2 or AaO 2 ), in agreement with the findings of previous workers [4,25,26]. However, since pathological abnormalities in asthma primarily occur on the ventilatory side of the 'pulmonary gas exchanger', we aimed at identifying whether any ventilatory derangement was closely associated with gas exchange characteristics.…”

Section: Relationship Between Airway Obstruction and Gas Exchange Impsupporting

confidence: 73%

“…It is well known that the existence and the degree of hypoxemia are linked to the worsening of clinical and spirometric measures [1,2,25]. However, a poor correlation has generally been found between the degree of hypoxemia or V A /Q distribution and the extent of reduction in air flow rates [4,25,26], whereas PaO 2 or AaO 2 values have been found closely related to V A /Q mismatch [5] or to pulmonary blood flow dispersion [10].…”

Section: Relationship Between Airway Obstruction and Gas Exchange Impmentioning

confidence: 91%

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Slow Compartment Features and Gas Exchange Impairment in Mild Asthma: Effects of Beta Agonist Inhalation

Valente

Rosa²,

Corbo³

et al. 1998

Respiration

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Static and dynamic lung volumes, arterial blood gases, alveolar ventilation and ventilation-perfusion (v̇_A/q̇) relationships were studied in 14 mild asthmatic patients and in 7 normal subjects (as controls) before and after fenoterol inhalation. Multiple nitrogen washout curves were analyzed by a bicompartmental distribution model, in order to assess the distribution of ventilation and v̇_A/q̇ mismatch. At baseline, asthmatics showed mild airway obstruction and gas exchange impairment [forced expiratory volume in 1 s (FEV₁) = 79% pred; PaO₂ = 87.4; alveolar-arterial oxygen tension gradient (AaPO₂) = 22.9 mm Hg]. By analysing nitrogen washout curves, an alveolar slow space representing 45.1% of total lung volume (vs. 36.8% in normals; p = 0.044) was identified; its alveolar ventilation per minute per unit lung volume (v̇_A2/L₂) was lower than in normals (p = 0.01). β-Agonist inhalation by the asthmatics, which reversed airway obstruction (FEV₁ = 98% pred.; p < 0.001) and improved gas exchange (PaO₂ = 92.6 mm Hg, p < 0.001; AaPO₂ = 16.8 mm Hg, p = 0.003), led to a highly significant increase in v̇_A2/L₂ (p = 0.001). The improvement in PaO₂ was associated with the increase in v̇_A2/L₂ (r² = 0.39; p = 0.017), but not with the increase in FEV₁. Lastly, the changes in FEV₁ and v̇_A2/L₂ were not correlated with each other. We conclude that even in mild stable asthma there is substantial unevenness of ventilation, detectable by bicompartmental analysis of nitrogen washout curves, which is responsible for gas exchange impairment and is not related to common spirometric parameters. In addition, the improvement in gas exchange is probably due to the effect of fenoterol on the tributary airways of the alveolar slow compartment. This effect can be assessed by this simple method, which can be used in clinical pharmacology studies and in the follow-up of asthmatic patients.

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Section: Relationship Between Airway Obstruction and Gas Exchange Impsupporting

confidence: 73%

Section: Relationship Between Airway Obstruction and Gas Exchange Impmentioning

confidence: 91%

Slow Compartment Features and Gas Exchange Impairment in Mild Asthma: Effects of Beta Agonist Inhalation

Valente

Rosa²,

Corbo³

et al. 1998

Respiration

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“…The great advantage of the body plethysmograph is that true lung volume is measured during a forced expiration. Furthermore, calculation of RV and TLC is rapid in the plethysmograph, and trapped air is measured, which may not be the case with helium dilution methods when there is severe airways obstruction (Meisner and Hugh-Jones, 1968). Flow displacement body plethysmographs have distinct advantages over pressure and volume displacement types, especially in ease and cost of construction, and are likely to become more widely available for routine use.…”

Section: Resultsmentioning

confidence: 99%

“…Maximum expiratory flow volume curves have been suggested as a more satisfactory test of airways obstruction because they reflect directly narrowing of the smaller airways . Gas dilution methods may underestimate lung volumes in the presence of airways obstruction because of trapped air (Meisner and Hugh-Jones, 1968). For this reason, measurements using a body plethysmograph are preferred as these estimate total intrathoracic gas volumes (Du Bois et al, 1956).…”

mentioning

confidence: 99%

Asthma--The Physiological and Clinical Spectrum in Childhood: Respiratory Function Studies in its Assessment

Hill¹,

Landau²,

McNicol³

et al. 1972

Archives of Disease in Childhood

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1972). Archives of Disease in Childhood, 47, 874. Asthma-the physiological and clinical spectrum in childhood: respiratory function studies in its assessment. Tests of respiratory function based on spirometry have hitherto proved of limited value in the assessment of asthmatic children in the interval phase. In an attempt to provide more information on this subject, respiratory function studies using a body plethysmograph were carried out in 106 asthmatic children aged 13 to 15 years during an asymptomatic period. The children were selected to cover the whole spectrum of asthma in childhood; they were divided into 4 grades on clinical criteria, and the results of the physiological studies compared with the clinical gradings.Results indicated that maximum expiratory flow volume curves, when combined with an estimation of lung volumes, provided the best assessment of the severity of a child's asthma.Using this test of respiratory function, most children in whom asthma had been a trivial complaint had virtually no abnormality, but a small number had mild airways obstruction. Those with chronic continuing asthma had evidence of severe airways obstruction and pulmonary hyperinflation. In children with episodic asthma, the degree of abnormality was variable and the frequency of the attacks seemed to be a major factor in determining this.It is concluded that respiratory function studies are a valuable tool in evaluating asthma in childhood, particularly when the clinical history is difficult to assess.

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“…The degree of hyper-inflation does not generally bear a direct relationship to the severity of asthma, as judged by measurements of FEV,, as has been noted previously (Engstrom, 1964;Meisner & Hugh-Jones, 1968;Woolcock & Read, 1966). The hyperinflation can be attributed to extensive narrowing of small airways, as a result of increased smooth muscle tone (Colebatch, Finucaine & Smith, 1973), oedema, secretions or a combination of these factors.…”

Section: Table 3 Mean Values Of Pre-'challenge' Measurements and Chamentioning

confidence: 77%

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

Benatar

König

1974

Clinical Science

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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 M E N 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.

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Pulmonary function in bronchial asthma.

Abstract: Head Injury-Lewin require help at an early stage. It is recommended that area coordinating services for head injuries be set up, and some rehabilitation centres developed to deal especially with particular injuries.

Cited by 42 publications

References 18 publications

Slow Compartment Features and Gas Exchange Impairment in Mild Asthma: Effects of Beta Agonist Inhalation

Slow Compartment Features and Gas Exchange Impairment in Mild Asthma: Effects of Beta Agonist Inhalation

Asthma--The Physiological and Clinical Spectrum in Childhood: Respiratory Function Studies in its Assessment

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

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