Exercise tests have been used for a long time as diagnostic tools for cardiac diseases. During recent years they have become more widely recognised as valuable instruments in the diagnosis and monitoring of pulmonary disorders. In the present issue of the European Respiratory Monograph, cardiopulmonary exercise testing for cardiac and pulmonary diseases has been presented. Techniques and equipment as well as reference values have been thoroughly described. The specific questions that arise in children have been addressed and exercise testing as a tool for the assessment of prognosis and treatment effects has been exhaustively presented. Since the last European Respiratory Monograph on exercise testing was published, this area has developed and there is a lot of new information, in particular regarding physical activity and exercise physiology associated with chronic obstructive pulmonary disease.
- European Respiratory Monograph
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- Page 1AbstractCorrespondence: B.J. Whipp, Centre for Sport and Exercise Sciences, Level 9, Worsley Building, University of Leeds, Leeds, LS2 9JT, UK. E-mail: B.Whipp@leeds.ac.uk
Maximum exercise in normal subjects is usually limited by perception of limb fatigue and in some cases by breathlessness. This usually results from an oxygen demand above the maximal conductance of the oxygen transport chain. Of the many tests available, an incremental test that provides a smooth gradual stress over the entire tolerance range is most appropriate for, at least initial, clinical investigations. The responses to exercise in patients should be interpreted with reference to the magnitude and pattern of the normal response.
- Page 36AbstractCorrespondence: S.A. Ward, Centre for Sport and Exercise Sciences, University of Leeds, Level 9, Worsley Building, Leeds, LS2 9JT, UK. E-mail: firstname.lastname@example.org
One of the major challenges in clinical exercise testing is to develop a means of distinguishing between the potential contributory mechanisms to the exercise intolerance that characterises most cardiopulmonary diseases, and to establish its dominant cause(s). Appropriately designed clinical exercise tests can: 1) expose abnormalities of physiological system function that contribute to exercise intolerance; and 2) provide a frame of reference for interventions designed to improve performance. Interpreting deviations from an expected response profile (i.e. characteristic of a reference population) from such tests requires a clear justification of their underlying physiological determinants.
- Page 69AbstractCorrespondence: D.E. O’Donnell, Division of Respiratory & Critical Care Medicine, Queen’s University, 102 Stuart Street, Kingston, ON, K7L 2V61 6135491459, Canada. E-mail: email@example.com
Abnormalities in cardiopulmonary responses to incremental cycle ergometer exercise are often similar in obstructive, restrictive and pulmonary vascular disorders. All are characterised by an accelerated ventilatory response, primarily as a result of the effects of a high fixed physiological dead space, combined, in many cases, with attendant arterial oxygen desaturation. Skeletal muscle deconditioning, with earlier metabolic acidosis, is also a common feature of all chronic respiratory disorders and can further amplify ventilatory stimulation during exercise. The breathing pattern is more rapid and shallow in both obstructive and restrictive lung disorders compared to health, and reflects the dynamic mechanical constraints on tidal volume (VT) expansion. In general, respiratory frequency responses to exercise are most pronounced in patients with restrictive lung disease. In chronic obstructive pulmonary disease, a VT plateau with concomitant tachypnoea early in exercise at relatively low ventilation generally indicates the presence of significant resting and additional dynamic lung hyperinflation. Cardiac frequency responses to exercise are variably abnormal, but are broadly similar across these disease groups and, therefore, nonspecific. Resting pulmonary function test results, in association with quantitative exercise flow–volume loop analysis, can accurately delineate abnormalities in resting and dynamic ventilatory mechanics that characterise obstructive and restrictive lung disease and permit easy differentiation from primary pulmonary vascular disorders. Such noninvasive assessments of ventilatory mechanics during exercise, together with the quantification of exertional symptoms, permit comprehensive clinical characterisation of the individual presenting with reduced exercise capacity.
- Page 93AbstractCorrespondence: P. Agostoni, Centro Cardiologico Monzino, IRCCS, Institute of Cardiology, University of Milan, via Parea 4, 20138 Milan, Italy39 258011039. E-mail: piergiuseppe.agostoni@CCFM.it
A cardiopulmonary exercise test (CPET) is often used in the functional and prognostic evaluation of patients with heart disease. As exercise tolerance cannot be predicted from resting cardiac and pulmonary function tests (e.g. echocardiography, spirometry), a CPET is particularly useful to properly evaluate the degree of exercise limitation and to identify its underlying causes. Furthermore, CPET is a very important tool in assessing the prognosis of cardiac patients, choosing the most effective treatment and evaluating the response to treatment.
- Page 108AbstractCorrespondence: J. Porszasz, Rehabilitation Clinical Trials Center, Los Angeles Biomedical Research Institute, 1124 W. Carson St, Torrance, CA 90502 USA1 3102228249. E-mail: firstname.lastname@example.org
Cardiopulmonary exercise testing (CPET) allows a comprehensive assessment of the mechanisms of exercise intolerance using a test that can generally be performed within 20 min. However, the test relies on a number of devices and sensors, and assessment will only be valid if all function correctly. It is the user’s responsibility to understand the equipment and measurements involved in the testing modality. Performance of the test on a cycle ergometer or a treadmill is an important choice, as each has advantages and disadvantages.
A central focus of the test measurements is calculation of the time course of pulmonary gas exchange. Although breath-by-breath analysis of oxygen uptake and carbon dioxide output is generally performed, this is a complex measurement technique requiring precise knowledge of the oxygen and carbon dioxide sensors and of the flow or volume sensors being used. Advances in the ability of digital computer analysis has led to the successful use of sensors with a number of operating principles and the ability to interpret breathing patterns with less than ideal characteristics. Tests involving elevated inspired oxygen levels present special measurement challenges. Consideration must also be given to heart rate measurement, ECG, blood pressure and pulse oximetry, which are all integral parts of the testing paradigm. A major focus in CPET is quality control, which should include both regular analysis of the performance of individual sensors and the assessment of overall system performance.
This overall analysis may include expired gas collection, use of a metabolic simulator and use of a “standard” human subject. The accuracy of the diagnostic conclusions of CPET will only be assured if the user is confident in the accuracy of the measurements.
- Page 129AbstractCorrespondence: R. Gosselink, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Division of Respiratory Rehabilitation, University Hospital Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium32 16329196. E-mail: email@example.com
Exercise and muscle testing have gained popularity in a variety of clinical conditions and, specifically, in pulmonary rehabilitation. Maximal incremental exercise testing has its main emphasis on the diagnosis of exercise intolerance and the mechanisms underlying this impairment. Field tests have their application mostly in longitudinal assessment of exercise performance, such as the evaluation of interventions. More detailed insight into skeletal (respiratory and peripheral) muscle function is obtained by specific assessment of muscle force and endurance. Therefore, these tests may complement routine exercise testing and help in indicating and tracking the effects of specific interventions addressing muscle weakness.
- Page 148AbstractCorrespondence: S. Singh, Pulmonary Rehabilitation Dept, University Hospitals of Leicester NHS Trust, Glenfield Hospital, Groby Road, Leicester, LE3 9QP44 1162563149, UK. E-mail: firstname.lastname@example.org
It is important to quantify an individual’s exercise capacity. Although laboratory-based tests (with the full complement of equipment) are acknowledged to be the gold standard, it is not always feasible or even desirable to complete such tests in an increasingly elderly and frail population. As a viable alternative, field tests have been developed.
Initially, this was a simple self-paced corridor-walking test. The later development of externally paced tests has imposed a defined protocol upon the participant. It is increasingly possible to collect complex physiological data beyond the laboratory, and studies have demonstrated that the externally paced tests, particularly the incremental shuttle walking test, best reflect the physiological response observed in comparable laboratory tests. Walking tests are simple to perform compared with laboratory-based tests, and require little expensive equipment in order to collect the most basic of data.
Field tests have been described in a number of patient populations with chronic cardiac and respiratory diseases. Studies have identified threshold values that are associated with successful clinical outcomes, or an increased mortality risk. Field test results are used as an outcome measure, particularly in rehabilitation studies, with the 6-min walking test and the incremental shuttle walking test being most frequently reported. Attempts have been made to describe what constitutes an important difference to the patient. In order to identify the maximal change achieved after an intervention, for example rehabilitation or pharmaceutical agents, a high-intensity endurance test yields the greatest improvements. In the field, this is provided by the endurance shuttle walking test.
If standardised, the field test yields information that can be usefully employed to evaluate the level of functional capacity and assess the outcome of therapies. For all patients, it is important that standardised procedures are followed in order to optimise their utility.
- Page 165AbstractCorrespondence: L. Puente-Maestu, Hospital General Universitario Gregorio Marañón, Servicio de Neumología, c/Doctor Ezquerdo 46 28007, Madrid, Spain34 15868018. E-mail: email@example.com
Exercise testing provides an array of measurements that characterise an individual’s physiological response. To decide whether a measured response is abnormal or not, observations have to be compared with mean reference values obtained from the study of large samples of, supposedly, healthy subjects.
There is certain biological inter-individual variability in the response to exercise between individuals. As this usually follows a normal distribution, the criterion to decide whether a response is abnormal is approximately twice the sd or the se of the estimates (regression equations) below or above the mean.
Many exercise responses are predicted by regression equations, which attempt to reduce the variability by accounting for the anthropometric characteristics of the subjects. When selecting reference values an important consideration that must be kept in mind is whether the individuals being tested match the population from which the reference values were obtained. This can be done by evaluating a group of representative healthy subjects as described in the present chapter.
This chapter intends to comprehensively evaluate the most relevant information regarding reference values of the physiological response to exercise in nonpathological populations. Several tables describe reference equations with brief methodological notes and information about the variability of the estimates (se) and the strength of the relationship (R2), when provided by the authors.
- Page 186AbstractCorrespondence: K-H. Carlsen, Voksentoppen, Paediatric Dept, Rikshospitalet-Radiumhospitalet Medical Center, Rikshospitalet University Hospital, Ullveien 14, NO 0791, Oslo47 2213505, Norway. E-mail: firstname.lastname@example.org
Paediatric exercise testing is becoming increasingly important for diagnosis in paediatric respiratory medicine. Testing for exercise-induced asthma (EIA) is still the most important and most frequently used exercise test for children. Standardisation of this test is very important, including standardisation of exercise load at a level of 90–95% of maximum exercise load and standardising environmental conditions, such as temperature, humidity and altitude. Treadmill running is most frequently used, but free range running and cycling are other options.
Exercise testing is important for the differential diagnosis of EIA. The most frequent differential diagnosis is exercise induced vocal cord dysfunction, which demonstrates inspiratory stridor at maximum performance during exercise testing.
Testing for physical fitness has become increasingly popular in paediatric respiratory medicine. Traditionally, a gradual stepwise protocol for exercise intensity has been used, but it has been shown that more short-term intensive protocols may give similar maximum oxygen uptakes and peak ventilation. The protocol may be varied according to the child’s condition. Cardiac illnesses usually require gradual stepwise protocols, whereas children with respiratory disorders manage a quicker protocol.
Of importance for respiratory diagnosis and assessment of possible physical training is measuring tidal breathing during exercise, which is obtainable through modern equipment.
- Page 195AbstractCorrespondence: P. Palange, Dept of Clinical Medicine, Pulmonary Function Unit, University of Rome “La Sapienza”, 00185 Rome, Italy, 39 6494021. E-mail: email@example.com
Exercise tolerance is recognised to be a good predictor of mortality in healthy subjects, ranging from young adults to the elderly. This also appears to be the case in a wide range of pulmonary and cardiovascular disease states. Data are available concerning the value of exercise indices in chronic obstuctive lung disease, interstitial lung disease (ILD), pulmonary vascular disease (PVD), cystic fibrosis and chronic heart failure (CHF). In these patients, the evaluation of the level of exercise tolerance, by cardiopulmonary exercise test (CPET) or by walking tests, has proven to be very useful not only for functional evaluation but also for prognostic evaluation. Scientific evidence also exists demonstrating that physiological measurements obtained during CPET (e.g. increased minute ventilation/carbon dioxide productions in CHF and in PVD) as well as during walking tests (e.g. arterial oxygen desaturation in ILD) provide additional important prognostic information. Exercise testing is recommended for pre-operative risk evaluation of candidates for major surgery and heart–lung transplantation. As pulmonary and cardiac function testing obtained at rest provide little prognostic information, exercise testing is recommended for the correct evaluation of patients with chronic pulmonary and cardiac diseases.
- Page 208AbstractCorrespondence: M.A. Spruit, Dept of Program Development & Education, Centre for Integrated Rehabilitation of Organ failure, Hornerheide 1, Horn, the Netherlands31 475587592. E-mail: firstname.lastname@example.org
Various whole-body exercise tests (cycle ergometry and treadmill walking) have been used for many years to determine: 1) the level of physical fitness; 2) which factors may limit exercise tolerance; and 3) the safety of exhaustive physical exercise in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD).
Whole-body exercise testing can also be of additional value in designing an exercise-training programme, to prescribe oxygen therapy, estimate daily physical activity levels, prescribe walking aids, assess quadriceps muscle fatigue, and as a stress model to investigate abnormal control of muscle metabolism and oxidative stress induction in patients with moderate-to-severe COPD.
Training load at the start of an exercise-training programme and tailored training components can be partially derived from the results of a symptom-limited incremental cycling test and a 6-min walking distance (6MWD) test. Moreover, 6MWD tests are used to prescribe oxygen therapy in normoxaemic COPD patients who suffer from exercise-induced oxygen desaturation. A 6MWD test can also be used to estimate the level of daily physical activity and to prescribe a walking aid, such as a rollator, to COPD patients with a low unaided 6MWD. In contrast to incremental and endurance shuttle walking tests, a high-intensity symptom-limited constant work-rate cycling test appears to be useful to discriminate between quadriceps muscle fatigue and dyspnoea as the dominant factor limiting exercise tolerance.
In conclusion, whole-body exercise testing can be of additional value in patients with moderate-to-severe COPD in evaluating the responses to different physiological and pharmacological interventions and in targeting novel treatment strategies.
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