Field tests in pulmonary disease

Proper evaluation of potential patients is the keystone to a successful pulmonary rehabilitation programme.1 The so-called functional approach which relates toimpairment (the physiological deficit),disability (total effect of impairment on the patient’s life), and handicap (the social disadvantages) as part of the comprehensive programme of care is one approach. It is useful not only for monitoring the patient’s functional status, but it enables the rehabilitation team to set and to achieve goals to improve the quality of the patient’s life.

Although an exercise test may help to uncover other coexisting diseases, it is generally necessary to assess the patient’s exercise tolerance and to evaluate possible blood gas changes which cannot be predicted from baseline lung function tests.2 The exercise test is also used to establish a safe and appropriate prescription for subsequent training. Cardiopulmonary exercise testing has been found to be useful in the evaluation of exercise tolerance in patients with dyspnoea and cardiopulmonary diseases. Compared with a clinical laboratory approach, it allows the detection of an underestimated circulatory component causing exercise limitation.3 Graded exercise testing has been shown to be useful in diagnosing patients with chronic unexplained dyspnoea although it was not sensitive in distinguishing a cardiac disease from deconditioning.4Variables measured and/or monitored during testing should include workload, heart rate, electrocardiogram, arterial oxygenation, and symptoms. Blood gas sampling during exercise adds a significant degree of complexity to testing. Non-invasive techniques such as cutaneous oximetry of arterial oxygen saturation are useful for continuous monitoring but should not be relied on for precise assessment of arterial oxygenation because of their limited accuracy.5Other measurements such as analysis of expired gas to calculate variables such as oxygen consumption (V˙o ₂) may be performed, depending on the interest and expertise of the referring physician, laboratory …