ERS technical standard on bronchial challenge testing: pathophysiology and methodology of indirect airway challenge testing.

Recently, this international task force reported the general considerations for bronchial challenge testing and the performance of the methacholine challenge test, a "direct" airway challenge test. Here, the task force provides an updated description of the pathophysiology and the methods to conduct indirect challenge tests. Because indirect challenge tests trigger airway narrowing through the activation of endogenous pathways that are involved in asthma, indirect challenge tests tend to be specific for asthma and reveal much about the biology of asthma, but may be less sensitive than direct tests for the detection of airway hyperresponsiveness. We provide recommendations for the conduct and interpretation of hyperpnoea challenge tests such as dry air exercise challenge and eucapnic voluntary hyperpnoea that provide a single strong stimulus for airway narrowing. This technical standard expands the recommendations to additional indirect tests such as hypertonic saline, mannitol and adenosine challenge that are incremental tests, but still retain characteristics of other indirect challenges. Assessment of airway hyperresponsiveness, with direct and indirect tests, are valuable tools to understand and to monitor airway function and to characterise the underlying asthma phenotype to guide therapy. The tests should be interpreted within the context of the clinical features of asthma.

Recommendations for a Standardized Pulmonary Function Report. An Official American Thoracic Society Technical Statement.

BACKGROUND: The American Thoracic Society committee on Proficiency Standards for Pulmonary Function Laboratories has recognized the need for a standardized reporting format for pulmonary function tests. Although prior documents have offered guidance on the reporting of test data, there is considerable variability in how these results are presented to end users, leading to potential confusion and miscommunication. METHODS: A project task force, consisting of the committee as a whole, was approved to develop a new Technical Standard on reporting pulmonary function test results. Three working groups addressed the presentation format, the reference data supporting interpretation of results, and a system for grading quality of test efforts. Each group reviewed relevant literature and wrote drafts that were merged into the final document. RESULTS: This document presents a reporting format in test-specific units for spirometry, lung volumes, and diffusing capacity that can be assembled into a report appropriate for a laboratory's practice. Recommended reference sources are updated with data for spirometry and diffusing capacity published since prior documents. A grading system is presented to encourage uniformity in the important function of test quality assessment. CONCLUSIONS: The committee believes that wide adoption of these formats and their underlying principles by equipment manufacturers and pulmonary function laboratories can improve the interpretation, communication, and understanding of test results.

ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.

This international task force report updates general considerations for bronchial challenge testing and the performance of the methacholine challenge test. There are notable changes from prior recommendations in order to accommodate newer delivery devices. Rather than basing the test result upon a methacholine concentration (provocative concentration (PC20) causing a 20% fall in forced expiratory volume in 1 s (FEV1)), the new recommendations base the result upon the delivered dose of methacholine causing a 20% fall in FEV1 (provocative dose (PD20)). This end-point allows comparable results from different devices or protocols, thus any suitable nebuliser or dosimeter may be used, so long as the delivery characteristics are known. Inhalation may be by tidal breathing using a breath-actuated or continuous nebuliser for 1 min (or more), or by a dosimeter with a suitable breath count. Tests requiring maximal inhalations to total lung capacity are not recommended because the bronchoprotective effect of a deep breath reduces the sensitivity of the test.

An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.

Field walking tests are commonly employed to evaluate exercise capacity, assess prognosis and evaluate treatment response in chronic respiratory diseases. In recent years, there has been a wealth of new literature pertinent to the conduct of the 6-min walk test (6MWT), and a growing evidence base describing the incremental and endurance shuttle walk tests (ISWT and ESWT, respectively). The aim of this document is to describe the standard operating procedures for the 6MWT, ISWT and ESWT, which can be consistently employed by clinicians and researchers. The Technical Standard was developed by a multidisciplinary and international group of clinicians and researchers with expertise in the application of field walking tests. The procedures are underpinned by a concurrent systematic review of literature relevant to measurement properties and test conduct in adults with chronic respiratory disease. Current data confirm that the 6MWT, ISWT and ESWT are valid, reliable and responsive to change with some interventions. However, results are sensitive to small changes in methodology. It is important that two tests are conducted for the 6MWT and ISWT. This Technical Standard for field walking tests reflects current evidence regarding procedures that should be used to achieve robust results.

An official systematic review of the European Respiratory Society/American Thoracic Society: measurement properties of field walking tests in chronic respiratory disease.

This systematic review examined the measurement properties of the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT) in adults with chronic respiratory disease. Studies that report the evaluation or use of the 6MWT, ISWT or ESWT were included. We searched electronic databases for studies published between January 2000 and September 2013. The 6-min walking distance (6MWD) is a reliable measure (intra-class correlation coefficients ranged from 0.82 to 0.99 in seven studies). There is a learning effect, with greater distance walked on the second test (pooled mean improvement of 26 m in 13 studies). Reliability was similar for ISWT and ESWT, with a learning effect also evident for ISWT (pooled mean improvement of 20 m in six studies). The 6MWD correlates more strongly with peak work capacity (r=0.59-0.93) and physical activity (r=0.40-0.85) than with respiratory function (r=0.10-0.59). Methodological factors affecting 6MWD include track length, encouragement, supplemental oxygen and walking aids. Supplemental oxygen also affects ISWT and ESWT performance. Responsiveness was moderate to high for all tests, with greater responsiveness to interventions that included exercise training. The findings of this review demonstrate that the 6MWT, ISWT and ESWT are robust tests of functional exercise capacity in adults with chronic respiratory disease.

Multi-ethnic reference values for spirometry for the 3-95-yr age range: the global lung function 2012 equations.

The aim of the Task Force was to derive continuous prediction equations and their lower limits of normal for spirometric indices, which are applicable globally. Over 160,000 data points from 72 centres in 33 countries were shared with the European Respiratory Society Global Lung Function Initiative. Eliminating data that could not be used (mostly missing ethnic group, some outliers) left 97,759 records of healthy nonsmokers (55.3% females) aged 2.5-95 yrs. Lung function data were collated and prediction equations derived using the LMS method, which allows simultaneous modelling of the mean (mu), the coefficient of variation (sigma) and skewness (lambda) of a distribution family. After discarding 23,572 records, mostly because they could not be combined with other ethnic or geographic groups, reference equations were derived for healthy individuals aged 3-95 yrs for Caucasians (n=57,395), African-Americans (n=3,545), and North (n=4,992) and South East Asians (n=8,255). Forced expiratory value in 1 s (FEV(1)) and forced vital capacity (FVC) between ethnic groups differed proportionally from that in Caucasians, such that FEV(1)/FVC remained virtually independent of ethnic group. For individuals not represented by these four groups, or of mixed ethnic origins, a composite equation taken as the average of the above equations is provided to facilitate interpretation until a more appropriate solution is developed. Spirometric prediction equations for the 3-95-age range are now available that include appropriate age-dependent lower limits of normal. They can be applied globally to different ethnic groups. Additional data from the Indian subcontinent and Arabic, Polynesian and Latin American countries, as well as Africa will further improve these equations in the future.

How should the lower limit of the normal range be defined?

Lung function parameters vary considerably with age and body size, so that, unlike many laboratory tests, the normal range of expected values must be individualized. For spirometry, only low values are considered to be abnormal, so the lower limit of normal (LLN) is taken to be equal to the 5th percentile of a healthy, non-smoking population. Simple and commonly used "rules of thumb," such as an FEV(1)/FVC < 0.70 to indicate air-flow obstruction, or assuming values < 80% of predicted to be abnormal, are inaccurate and will cause misclassification, specifically under-diagnosis of abnormalities in younger, taller individuals and over-diagnosis in those older or shorter. A much more accurate LLN for the FEV(1)/FVC ratio, which recognizes the change with age of this measurement, can be easily determined by subtracting 10 (10% or 0.10) from the age specific FEV(1)/FVC predicted for any individual. The analysis and mathematical descriptions of reference data have become increasingly sophisticated in recent years, but the interpretation of values near the LLN continues to carry uncertainty, due to an overlap in values between low normal values and those reflecting early disease. Among patients referred to a pulmonary function laboratory, the pre-test probability of disease may be relatively high, so that even individuals with values above the LLN may be more likely than not to have respiratory disease. A future goal for the pulmonary community would be the development of risk stratified outcome data that would allow an estimation of the probability of disease with progressive decrements in lung function. While interpreting spirometry results near the LLN will continue to be problematic, a more important task for the pulmonary community is to focus on finding the pool of individuals with clear-cut, but undiagnosed, COPD. And for this, good quality spirometry remains the best tool and must be widely available.

Fellows as teachers: the teacher-assistant experience during pulmonary subspecialty training.

STUDY OBJECTIVES: Physicians undergoing medical subspecialty training, referred to as "fellows" in the United States, often serve as small group tutors. There are few reports, however, on whether fellows benefit from their experience teaching in the classroom. The purpose of this article is to describe the teacher-assistant requirement for fellows in a pulmonary and critical care training program and gain the perspectives of program graduates on their experiences as teacher assistants. DESIGN, SETTING, AND PARTICIPANTS: The structure of the teacher-assistant requirement is described in detail. We also surveyed 55 consecutive graduates of our Pulmonary and Critical Care Fellowship program located in the United States on the educational value of teaching pathophysiology to preclinical medical students. RESULTS: Fellows and one or two faculty members co-teach groups of 15 to 25 second-year medical students during 22 h of case-based conferences over a 6-week period. Weekly meetings for teacher assistants foster improved teaching skills and provide insight into the basic tenets of structuring and implementing the course. Fellows receive formal and informal feedback on their performance. Fifty of 55 graduates (91%) returned the survey. Respondents rated the acquisition of teaching skills and knowledge of pulmonary pathophysiology as the most useful aspects of their experience. Eighty-seven percent rated their overall experience favorably, and 90% agreed that teaching the course should remain a curriculum requirement. The responses of physicians in academic and community practice were comparable. CONCLUSIONS: Graduates of our Pulmonary and Critical Care Fellowship valued their teacher-assistant experience. This article may serve as a model for other subspecialty programs that are interested in formally incorporating teaching into their training program and may provide an impetus for the additional exploration of teacher-assistant experiences at other institutions.