MEDizzy - Match each of the following pulmonary function test results

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Disorders of the Respiratory System and Critical Care Illness

Match each of the following pulmonary function test results to the respiratory disorder in which it is most likely to be found. Chronic obstructive pulmonary disease?

ExplanationThe ventilatory function can be easily measured with lung volume measurement and the FEV1/FVC ratio. A decreased FEV1/FVC ratio is characteristic of obstructive lung diseases. Alternatively, low lung volumes, specifically decreased total lung capacity (TLC), and occasionally decreased residual volume (RV) are characteristic of restrictive lung diseases. With extensive air trapping in obstructive lung disease, TLC is often increased, and RV may also be increased. Vital capacity (VC) is proportionally decreased. Maximal inspiratory pressure (MIP) measures respiratory muscle strength and is decreased in patients with neuromuscular disease. Thus, myasthenia gravis will produce low lung volumes and decreased MIP, whereas patients with idiopathic pulmonary fibrosis will have normal muscle strength and subsequently a normal MIP but decreased TLC and RV. In some cases of pulmonary parenchymal restrictive lung disease, the increase in elastic recoil results in an increased FEV1/FVC ratio. The hallmark of obstructive lung disease, such as chronic obstructive pulmonary disease (COPD), is a decreased FEV1/FVC ratio.