[Cardiopulmonary exercise testing in occupational medical fitness examination and assessment]

Medical expert opinion by occupational physicians and pneumologists has two main objectives: making a diagnosis with probability bordering on certainty and clarifying a causal relationship to a present or former occupational exposure to irritant toxic, allergenic or fibrosing dusts, gases, welding fumes or mineral fibres. Especially for conditions that are associated with exertional dyspnea, the diagnosis at rest using spirometry, body plethysmography, pulmonary function test, blood gas analysis, electrocardiogram and echocardiography is of limited use. This paper identifies the indications for cardiopulmonary exercise testing (CPET) in occupational medicine, explains the related measurements and their differential diagnostic value with special consideration of the flow-volume curve under exercise as well as the alveolar-arterial oxygen gradient. Diagnostic statements on the relevance of oxygen uptake measured at continuous and peak load compared to the wattage ascertained on the bicycle ergometer are presented. Characteristic CPET findings are explained in terms of their differential diagnostic significance. Furthermore, the importance of CPET for the assessment of occupational disease-related functional loss (clinical proportions in the reduction of working capacity) is shown.