Clinical Exercise Testing
Section snippets
TYPES OF CLINICAL EXERCISE TESTING
Clinical exercise testing increasingly is being used in clinical practice for two main reasons—its impact in the clinical decision-making process and a growing awareness that resting cardiopulmonary measurements do not provide a reliable estimate of functional capacity. Several modalities of clinical exercise testing are used in clinical practice. Some provide basic information, have low technical requirements, and are simple to perform; others provide a more complete assessment of all the
CARDIOPULMONARY EXERCISE TEST
Cardiopulmonary exercise testing involves measuring oxygen uptake (o2), carbon dioxide output (co2), minute ventilation (e), and other variables in addition to monitoring 12-lead ECG, blood pressure, and pulse oximetry (Spo2) during a maximal symptom-limited incremental exercise test on the cycle ergometer or treadmill. When appropriate, the additional measurement of arterial blood gases provides important information on pulmonary gas exchange.
REASONS TO PERFORM CARDIOPULMONARY EXERCISE TESTING
Cardiopulmonary exercise testing (CPET) provides information not available from the previously described clinical exercise testing modalities. Cardiopulmonary exercise testing permits: (1) objective determination (o2max) of functional capacity and impairment, (2) evaluation of the mechanisms of exercise limitation, such as the contribution of different organ systems involved in exercise (i.e., heart, lungs, blood, skeletal muscles), (3) differentiation between heart and lung disease, (4)
CLINICAL INDICATIONS
Comprehensive CPET is useful in a wide spectrum of clinical settings125:
Evaluation of exercise intolerance and unexplained dyspnea Functional impairment (o2 peak) Exercise limitation: determination of factors and pathophysiologic mechanisms Assessing contribution of cardiac and pulmonary causes in coexisting disease Symptoms disproportionate to resting pulmonary and cardiac tests When initial resting cardiopulmonary testing is nondiagnostic Heart failure Selection for cardiac transplantation Exercise prescription and monitoring response to cardiac
Evaluation of patients with cardiovascular disease
METHODOLOGY AND PROTOCOLS
Conventional equipment used for the measurement of cardiopulmonary variables uses automated systems that provide on-line breath-by-breath analysis of respiratory gas exchange. The subject breathes through a mouthpiece connected to a flow measurement device (pneumotachograph, mass flow sensor, pitot apparatus, and so forth); oxygen and carbon dioxide fractions are measured by a fuel cell (zirconium oxide) and infrared analyzer, respectively, or both by a mass spectrometer, and heart rate by an
MEASUREMENTS
Computerized exercise systems permit an impressive number of variables to be measured during CPET (Table 1). A list of selected peak CPET measurements and suggested normal guidelines for interpretation (Table 2) also is included.126
NORMAL CARDIOPULMONARY EXERCISE TEST RESPONSE
The graphic representation of the normal cardiopulmonary response of a healthy, physically active, young person to a symptom-limited maximal incremental exercise test appears in Figure 4.
The upper panel shows oxygen uptake (o2), carbon dioxide output (co2), and minute ventilation (e) increasing as work rate increases. The increase in o2 is linear with increases in work rate. During the early stages of exercise, co2 and e also increase linearly with o2, until approximately 50% to 60% of o2max,
EXERCISE LIMITATION
Clinically, it is increasingly appreciated that exercise limitation or low o2max achieved is multifactorial and, as such, is not limited by any single component of the oxygen transport or use process, but, rather, by their collective quantitative interaction.34, 58, 118 Although several factors may be involved, one factor often predominates, with variable contributions to exercise intolerance from the other factors. Exercise in normal subjects is limited mainly by the cardiovascular system. The
Interpretative Strategies
Several approaches to interpretation of CPET results should be considered because there is no consensus on any one interpretative strategy. Approaches that emphasize the mechanism for exercise limitation (i.e., ventilatory limitation to exercise) are limited by their lack of “gold standard” definition and the realization that exercise limitation is often multifactorial. Algorithms based on key measurements and conceptual framework39, 85, 121 are limited by excessive reliance on single
PUTTING IT ALL TOGETHER
The integrative approach to CPET interpretation involves analyzing the quality of the test and the consistency of results; comparing results with appropriate reference values57, 121; identifying physiologic limitations and patterns of exercise responses; considering which clinical entities may be associated with these patterns (Fig. 5 and Table 3); and correlating these results with other available studies, important patient information, and reasons for which CPET was requested. Accurate
References (135)
- et al.
Noninvasive determinations of the anaerobic threshold. Reliability and validity in patients with COPD
Chest
(1992) - et al.
Prediction of maximum exercise tolerance in patients with COPD
Chest
(1991) Physiologic responses to training
Clin Chest Med
(1994)- et al.
Stability of improvements in exercise performance and quality of life following bilateral lung volume reduction surgery in severe COPD
Chest
(1997) - et al.
Asthma and exercise
Clin Chest Med
(1994) - et al.
Comparison of progressive exercise performance of normal subjects and patients with primary pulmonary hypertension
Chest
(1987) - et al.
An algorithm for the interpretation of cardiopulmonary exercise tests
Chest
(1990) Exercise limitation and clinical exercise testing in chronic obstructive pulmonary disease
Clin Chest Med
(1994)- et al.
Role of exercise stress testing in preoperative evaluation of patients for lung resection
Clin Chest Med
(1994) - et al.
How should we measure function in patients with chronic heart and lung disease?
J Chronic Dis
(1985)
Pathophysiology of activity limitation in patients with interstitial lung disease
Chest
The role of cardiopulmonary exercise testing in lung and heart-lung transplantation
Clin Chest Med
Ventilatory constraints during exercise in patients with chronic heart failure
Chest
Advances in pulmonary laboratory testing
Chest
Emerging concepts in the evaluation of ventilatory limitation during exercise. The exercise tidal flow-volume loop
Chest
Mechanisms of exertional dyspnea
Clin Chest Med
Inaccuracy of non-invasive estimates of VD/VT in clinical exercise testing
Chest
Prediction of maximal exercise capacity in obstructive and restrictive pulmonary disease
Chest
Pulmonary factors limiting exercise capacity in patients with heart failure
Prog Cardiovasc Dis
Clinical exercise testing in chronic airflow limitation
Med Clin North Am
Clinical exercise testing in interstitial lung disease
Clin Chest Med
Graded comprehensive cardiopulmonary exercise testing in the evaluation of dyspnea unexplained by routine evaluation
Chest
Exercise testing in the evaluation of patients at high risk for complications from lung resection
Chest
Dangerous curves: A perspective on exercise, lactate, and the anaerobic threshold
Chest
Can maximal cardiopulmonary capacity be recognized by a plateau in oxygen uptake?
Chest
The evolving role of exercise testing prior to lung resection
Chest
Maximal exercise testing for the selection of heart transplantation candidates: Limitation of peak oxygen consumption
Chest
Exercise alveolar-arterial oxygen pressure difference in interstitial lung disease
Chest
Clinical practice guideline: Exercise testing for evaluation of hypoxemia and/or desaturation
Respir Care
Evidence-based guidelines for pulmonary rehabilitation
Chest
ACC/AHA/ACP-ASIM: Guidelines for the management of patients with chronic stable angina: Executive summary and recommendations
Circulation
ACC/AHA guidelines for exercise testing. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing)
J Am Coll Cardiol
Evaluation of breathlessness in asbestos workers
Am Rev Respir Dis
Measurement of feelings using visual analogue scales
Proc R Soc Med
Guidelines for exercise testing and prescription
Exercise standards. A statement for healthcare professionals
Circulation
Guidelines for methacholine and exercise challenge testing-1999
Am J Respir Crit Care Med
Evaluation of impairment/disability secondary to respiratory disorders
Am Rev Respir Dis
Official Statement. Pulmonary rehabilitation-1999
Am J Respir Crit Care Med
Ventilation: Total, alveolar, and dead space
Textbook of Work Physiology: Physiological Bases of Exercise
Mechanical ventilatory constraints in aging, lung disease, and obesity: Perspective and brief review
Med Sci Sports Exerc
Effect of mild-to-moderate airflow limitation on exercise capacity
J Appl Physiol
Inhaled bronchodilators reduce dynamic hyperinflation during exercise in patients with chronic obstructive pulmonary disease
Am J Respir Crit Care Med
Lung volume reduction surgery improves maximal O2 consumption, maximal minute ventilation, O2 pulse, and dead space-to-tidal volume ratio during leg ergometry
Am J Respir Crit Care Med
Exercise capacity as a predictor of postoperative complications in lung resection candidates
Am J Respir Crit Care Med
Functional evaluation of the lung resection candidate
Eur Respir J
Psychophysical bases of perceived exertion
Med Sci Sports Exerc
Current concepts in lactate exchange
Med Sci Sports Exerc
Cited by (82)
Role of cardiopulmonary exercise testing as a risk-assessment method in patients undergoing intra-abdominal surgery: A systematic review
2016, British Journal of AnaesthesiaCitation Excerpt :Cardiopulmonary exercise testing can be implemented to aid clinical decision-making. These uses include assessing patients with significant complaints of exercise intolerance and dyspnoea1 and determining the severity impairment related to heart failure and chronic obstructive pulmonary disease.2 Cardiopulmonary exercise testing is used as a preoperative risk-stratification tool to predict postoperative mortality, length of stay (LOS), and morbidity; however, its role requires validation.
A Machine Learning approach to classify ventilatory efficiency
2023, 2023 IEEE International Conference on Metrology for eXtended Reality, Artificial Intelligence and Neural Engineering, MetroXRAINE 2023 - ProceedingsCardiopulmonary exercise test: A 20-year (2002-2021) bibliometric analysis
2022, Frontiers in Cardiovascular Medicine
Address reprint requests to Idelle M. Weisman, MD, Department of Clinical Investigation, William Beaumont Army Medical Center, 5005 N. Piedras St., El Paso, TX 79920–5001, e-mail:weisman@aol.com