Lung Hyperinflation and Its Reversibility in Patients with Airway Obstruction of Varying Severity

Deesomchok, Athavudh; Webb, Katherine A.; Forkert, Lutz; Lam, Yuk-Miu; Ofir, Dror; Jensen, Dennis; O’Donnell, Denis E.

doi:10.3109/15412555.2010.528087

Cited by 103 publications

(105 citation statements)

References 35 publications

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“…In addition to serving as an index for survival, IC has also emerged as a useful tool for assessing changes in gas trapping for various therapies. For example, Van Noord and co-workers 37 39 Notably, they found an increased RV in mild, moderate, and severe obstruction. They also observed that the largest change in percent of predicted following bronchodilator and the frequency of a positive response was greatest for RV ( Fig.…”

Section: Do Lung Volumes Tell Us Anything Meaningfulmentioning

confidence: 99%

What Is the Clinical Value of Lung Volumes?

Ruppel

2012

Respir Care

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Lung volumes are considered part of a complete pulmonary function test, but their value for enhancing clinical decision making is unknown. Unlike spirometry and diffusing capacity of the lung for carbon monoxide (D LCO ), which do contribute to confirming or excluding a diagnosis, there are few clear indications when lung volumes are discriminatory. Confirming "restriction" when vital capacity (VC) or FVC is reduced is perhaps the most important. A restrictive pattern can have many etiologies, and clinicians often use VC or FVC as a primary index of lung volume. This makes "physiologic" sense because, in healthy subjects, and in patients with true restriction, VC comprises most of the total lung capacity (TLC). Mixed obstruction-restriction and the nonspecific pattern (ie, reduced FVC and FEV 1 , normal FEV 1 /FVC and TLC) require measuring TLC to confirm the underlying physiology. In obesity, VC and TLC may remain within normal limits, but functional residual capacity (FRC) can exponentially decrease. Increased lung volumes, particularly residual volume (RV), are commonly observed in airway obstruction. TLC may be normal, but is frequently increased in the late stages of COPD. Hyperinflation and air-trapping are terms commonly used to reflect these changes, but are not well standardized. The variability of lung volumes related to degree of obstruction suggests that measuring gas-trapping may be needed to monitor therapy. Changes in inspiratory capacity, RV, or FRC may be important gauges of response to bronchodilators or other hyperinflation-reducing therapies. How lung volumes are measured may be important, especially in patients who have moderate or severe airway obstruction. Body plethysmography is often considered more accurate than gas dilution methods in the presence of obstruction. However, the differences between techniques are not completely understood. Newer approaches such as computed tomography, although not suitable for routine testing, may help to delineate the true underlying physiology.

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Section: Do Lung Volumes Tell Us Anything Meaningfulmentioning

confidence: 99%

What Is the Clinical Value of Lung Volumes?

Ruppel

2012

Respir Care

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“…The natural evolution of hyperinflation in patients with COPD is unclear, but data suggest that it can present even in patients with mild COPD, and increases exponentially as disease severity worsens [37]. On a related note, there is increasing evidence supporting the correlation of CT-derived emphysema assessment with physiological markers of hyperinflation (most commonly RV, RV/TLC and resting IC and FRC) [38][39][40][41][42].…”

Section: Characteristics Of the Eh Phenotype: Hyperinflationmentioning

confidence: 99%

“…Some also have a positive effect on exacerbation rates, healthcare utilisation and, possibly, mortality [93,94,96,[113][114][115][116][117][118]. One study highlighted the fact that bronchodilators predominantly exert their effects on measures of resting hyperinflation, even when little or no change in FEV1 is observed [37]. In addition, a study investigating the predictors of improvement in exercise tolerance following treatment of short-acting bronchodilator (ipratropium bromide, three times a day for a 3-week period) found that an increased resting IC was the best predictor of change in endurance time following bronchodilation, and that the change in FEV1 was not [119].…”

Section: Treatmentmentioning

confidence: 99%

The clinical relevance of the emphysema-hyperinflated phenotype in COPD

et al. 2015

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The classification of chronic pulmonary obstructive disease (COPD) into clinical and pathophysiological subsets is not new, but increasing data is available on the relation of these different phenotypes to clinically meaningful outcomes. This review focuses on the "emphysema-hyperinflation" (EH) phenotype, which is characterised by a prominent loss of lung elastic recoil and hyperinflation burden that translates into marked exercise intolerance and a heightened sense of dyspnoea. Although no single genetic profile has been associated with the EH phenotype, recent data have shown that certain single nucleotide polymorphisms, such as DNAH5, appear to have an effect on the preferential development of hyperinflation in smokers. Static and dynamic hyperinflation are hallmarks of the EH phenotype, and abnormal increases in resting lung function indices such as total lung capacity (TLC), functional residual capacity (FRC) and inspiratory to TLC ratio (IC/TLC) seem more associated with the clinical EH phenotype than others markers of gas trapping. An increased level of dyspnoea on exertion and exercise intolerance are also characteristic of the EH presentation and are likely related in part to critical mechanical constraints imposed on tidal volume expansion in situations where ventilatory demands are increased, but also possibly on cardiac and hemodynamic anomalies related to emphysema and hyperinflation. Importantly, the clinical relevance of the EH phenotype is underlined by the finding that indices of hyperinflation such as IC/TLC and residual volume (RV) can be used as independent predictors of mortality in patients with COPD. Treatment of patients with the EH phenotype should primarily focus on smoking cessation and maximal bronchodilator therapy. New long-acting combined bronchodilators options provide clinicians with safe and effective ways to address the hyperinflation issue in this population. Pulmonary rehabilitation also has a positive impact on exercise tolerance, quality of life and hyperinflation, and should be routinely considered in patients with EH presentation that remain symptomatic despite optimal treatment, whereas as lung volume reduction techniques should be reserved for highly selected patients.

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“…Lung-volume measurements are used infrequently but may show significant changes, particularly in the presence of hyperinflation or air trapping. 23 Airway resistance and conductance, measured by body plethysmography, often improve significantly even though FEV 1 does not. Because of the variability in airway resistance and conductance in healthy subjects, improvements of 40 -50% are necessary to conclude that reversibility is present.…”

Section: Bronchodilator Testingmentioning

confidence: 99%

Aerosol Use in the Pulmonary Function Lab

Ruppel

2015

Respir Care

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Aerosols in the Pulmonary Aerosols in the Pulmonary Function Testing LabAerosolized agents are an essential component of pulmonary function testing (PFT). 1 Inhaled bronchodilators are widely used to assess reversibility of airway obstruction, particularly in patients suspected of having asthma. 2 Measurement of the FEV 1 /FVC ratio after administration of a ␤ agonist is the de facto test to establish the diagnosis of COPD. 3 Similarly, measurement of FEV 1 following bronchodilator administration is used to categorize the severity of airway obstruction. Improvement in air flow is the primary end point in the evaluation of new inhaled bronchodilators, and PFT provides the necessary tools for assessment. The other primary use of aerosols in the PFT lab involves inhaled bronchial challenge agents. As is the case for bronchodilators, bronchial provocation using an aerosolized agent is a key tool for making or excluding the diagnosis of asthma. 4 Inhalation of challenge aerosols also provides a means to quantify the degree of hyper-responsiveness. How Aerosols Are Administered in the PFT Lab BronchodilatorsBronchodilators can be administered by various methods for diagnostic purposes. Typically, a ␤ agonist or anMr Ruppel is affiliated with the Division

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Lung Hyperinflation and Its Reversibility in Patients with Airway Obstruction of Varying Severity

Cited by 103 publications

References 35 publications

What Is the Clinical Value of Lung Volumes?

What Is the Clinical Value of Lung Volumes?

The clinical relevance of the emphysema-hyperinflated phenotype in COPD

Aerosol Use in the Pulmonary Function Lab

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