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SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” 

Edited by V. Brusasco, R. Crapo and G. Viegi 

Number 2 in this Series

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Standardisation of spirometry

SERIES “ATS/ERS TASK FORCE: STANDARDISATION OF LUNG FUNCTION TESTING” 

Edited by V. Brusasco, R. Crapo and G. Viegi 

Number 5 in this Series 







This section is written to provide guidance in interpreting pulmonary function tests (PFTs) to medical directors of hospital-based laboratories that perform PFTs, and physicians who are responsible for interpreting the results of PFTs most commonly ordered for clinical purposes. Specifically, this section addresses the interpretation of spirometry, bronchodilator response, carbon monoxide diffusing capacity ( D L,CO) and lung volumes.

The sources of variation in lung function testing and technical aspects of spirometry, lung volume measurements and D L,CO measurement have been considered in other documents published in this series of Task Force reports 1–4 and in the American Thoracic Society (ATS) interpretative strategies document 5.

An interpretation begins with a review and comment on test quality. Tests that are less than optimal may still contain useful information, but interpreters should identify the problems and the direction and magnitude of the potential errors. Omitting the quality review and relying only on numerical results for clinical decision making is a common mistake, which is more easily made by those who are dependent upon computer interpretations.

Once quality has been assured, the next steps involve a series of comparisons 6 that include comparisons of test results with reference values based on healthy subjects 5, comparisons with known disease or abnormal physiological patterns ( i.e. obstruction and restriction), and comparisons with self, a rather formal term for evaluating change in an individual patient. A final step in the lung function report is to answer the clinical question that prompted the test.

Poor choices made during these preparatory steps increase the risk of misclassification, i.e. a falsely negative or falsely positive interpretation for a lung function abnormality or a change …

https://erj.ersjournals.com/content/erj/26/5/948.full.pdf

Interpretative strategies for lung function tests

Lung volumes are subdivided into static and dynamic lung volumes. Static lung volumes are measured by methods which are based on the completeness of respiratory manoeuvres, so that the velocity of the manoeuvres should be adjusted accordingly. The measurements taken during fast breathing movements are described as dynamic lung volumes and as forced inspiratory and expiratory flows.

### 1.1 Static lung volumes and capacities

The volume of gas in the lung and intrathoracic airways is determined by the properties of lung parenchyma and surrounding organs and tissues, surface tension, the force exerted by respiratory muscles, by lung reflexes and by the properties of airways. The gas volumes of thorax and lung are the same except in the case of a pneumothorax. If two or more subdivisions of the total lung capacity are taken together, the sum of the constituent volumes is described as a lung capacity. Lung volumes and capacities are described in more detail in § 2.

#### 1.1.1 Determinants

Factors which determine the size of the normal lung include stature, age, sex, body mass, posture, habitus, ethnic group, reflex factors and daily activity pattern. The level of maximal inspiration (total lung capacity, TLC) is influenced by the force developed by the inspiratory muscles (disorders include e.g. muscular dystrophy), the elastic recoil of the lung (disorders include e.g. pulmonary fibrosis and emphysema) and the elastic properties of the thorax and adjacent structures (disorders include e.g. ankylosis of joints). The level of maximal expiration (residual volume, RV) is determined by the force exerted by respiratory muscles (disorders include e.g. muscle paralysis), obstruction, occlusion and compression of small airways (disorders include e.g. emphysema) and by the mechanical properties of lung and thorax (disorders include diffuse fibrosis, kyphoscoliosis).

Assessing the total lung capacity is indispensable in establishing a restrictive ventilatory defect or in diagnosing abnormal lung distensibility, as may occur in patients …

Lung volumes and forced ventilatory flows

Executive Summary Objectives Participants Evidence Validation Key Messages Introduction Rationale for a Change in the Approach to Classification of Idiopathic Interstitial Pneumonias Development of a New Classification of Idiopathic Interstitial Pneumonia Current Classification of IIP New ATS/ERS Classification Principles Guiding the Assessment of Patients with Idiopathic Interstitial Pneumonias The Diagnostic Process Is Dynamic Clinical Evaluation Radiological Evaluation Role of Surgical Lung Biopsy Unclassifiable Interstitial Pneumonia Bronchoalveolar Lavage Fluid Evaluation Idiopathic Pulmonary Fibrosis Clinical Features Radiologic Features Histologic Features IPF: Areas of Uncertainty Nonspecific Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features NSIP: Areas of Uncertainty Cryptogenic Organizing Pneumonia Clinical Features Radiologic Features Histologic Features COP: Areas of Uncertainty Acute Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features AIP: Areas of Uncertainty Respiratory Bronchiolitis-Associated Interstitial Lung Disease Clinical Features Radiologic Features Histologic Features RB-ILD: Areas of Uncertainty Desquamative Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features DIP: Areas of Uncertainty Lymphoid Interstitial Pneumonia Clinical Features Radiologic Features Histologic Features LIP: Areas of Uncertainty References Appendix

American thoracic society/European respiratory society international multidisciplinary consensus classification of the idiopathic interstitial pneumonias

Background: In 2002 the American Thoracic Society/European Respiratory Society (ATS/ERS) classification of idiopathic interstitial pneumonias (IIPs) defined seven specific entities, and provided standardized terminology and diagnostic criteria. In addition, the historical “gold standard” of histologic diagnosis was replaced by a multidisciplinary approach. Since 2002 many publications have provided new information about IIPs.Purpose: The objective of this statement is to update the 2002 ATS/ERS classification of IIPs.Methods: An international multidisciplinary panel was formed and developed key questions that were addressed through a review of the literature published between 2000 and 2011.Results: Substantial progress has been made in IIPs since the previous classification. Nonspecific interstitial pneumonia is now better defined. Respiratory bronchiolitis–interstitial lung disease is now commonly diagnosed without surgical biopsy. The clinical course of idiopathic pulmonary fibrosis and nonspecific inte...

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An Official American Thoracic Society/European Respiratory Society Statement: Update of the International Multidisciplinary Classification of the Idiopathic Interstitial Pneumonias

In 50 of 94 patients with bronchiolitis obliterans we found no apparent cause or associated disease, and the bronchiolitis obliterans occurred with patchy organizing pneumonia. Histologic characteristics included polypoid masses of granulation tissue in lumens of small airways, alveolar ducts, and some alveoli. The fibrosis was uniform in age, suggesting that all repair had begun at the same time. The distribution was patchy, with preservation of background architecture. Clinically, there was cough or flu-like illness for 4 to 10 weeks, and crackles were heard in the lungs of 68 per cent of the patients. Radiographs showed an unusual pattern of patchy densities with a "ground glass" appearance in 81 per cent. Physiologically, there was restriction in 72 per cent of the patients, and 86 per cent had impaired diffusing capacity. Obstruction was limited to smokers. The mean follow-up period was four years. With corticosteroids, there was complete clinical and physiologic recovery in 65 per cent of the subjects; two died from progressive disease. This disorder differs from bronchiolitis obliterans with irreversible obstruction. It was confused most often with idiopathic pulmonary fibrosis. In view of the benign course and therapeutic response, a histologic distinction is important.

Bronchiolitis obliterans organizing pneumonia.

We undertook this study to determine the prevalence of normal roentgenograms in chronic diffuse infiltrative lung diseases. Of 458 patients with such disorders histologically confirmed, 44, or 9.6 per cent, had normal pre-biopsy films. In this group with normal x-ray films, desquamative interstitial pneumonia, sarcoidosis and allergic alveolitis were the most frequent diagnoses. Dyspnea was the principal complaint, and fine rales were common. The vital capacity was reduced in 57 per cent, and the single-breath diffusing capacity in 71 per cent. In half, histologic changes and functional impairment were moderately severe. Films may be normal in such cases because isolated foci are too small or too few, because diffuse interstitial or intra-alveolar disease may cast no discrete shadows or because the lesions primarily affect airways or blood vessels. Patients with normal chest roentgenograms and normal mechanics of breathing but with impaired gas exchange should have lung biopsy for early diagnosis...

Normal chest roentgenograms in chronic diffuse infiltrative lung disease.

Isoniazid-associated hepatitis in 114 patients.

Bronchiolar disorders can be divided into 2 general categories: (1) airway disorders (cellular bronchiolitis and obliterative bronchiolitis) and (2) parenchymal disorders (respiratory bronchiolitis-interstitial lung disease, which occurs in smokers and is treatable with smoking cessation or corticosteroid therapy, and bronchiolitis obliterans organizing pneumonia, an inflammatory lung disease simultaneously involving the terminal bronchioles and alveoli). This article reviews the clinical findings and therapeutic management of bronchiolitis obliterans organizing pneumonia.

Bronchiolitis Obliterans Organizing Pneumonia

Benign asbestos effusion was defined by (1) exposure to asbestos, (2) confirmation by roentgenograms or thoracenteses, (3) no other disease related to pleural effusion, and (4) no malignant tumor within three years. There were 34 benign effusions among 1,135 exposed workers compared with no otherwise unexplained effusions among 717 control subjects. Prevalence was dose related with 7.0%, 3.7%, and 0.2% effusions with severe (III), indirect (II), and peripheral (I) exposure, respectively. The latency period was shorter than for other asbestos-related disorders. Benign effusion was the most common asbestos-related abnormality during the first 20 years after exposure. Incidence studies showed 9.2 effusions per 1,000 person-years for level III exposure, 3.9 for level II, and 0.7 for level I. Most effusions were small; 28.6% recurred, and 66% were asymptomatic. There was one mesothelioma six years after effusion. Asbestos exposure should be carefully searched for in patients with "idiopathic" pleural effusion. ( JAMA 1982;247:617-622)

Gary R. Epler

Papers

Bronchiolitis obliterans organizing pneumonia.

Normal chest roentgenograms in chronic diffuse infiltrative lung disease.

Isoniazid-associated hepatitis in 114 patients.

Bronchiolitis Obliterans Organizing Pneumonia

Prevalence and Incidence of Benign Asbestos Pleural Effusion in a Working Population