Lung function is measured by various tests, including the pulmonary function test (PFT), arterial blood gases (ABG) analysis, and oxygen desaturation during exercise. These tests can evaluate symptoms and signs of lung disease, reveal the cause of breath shortness, and may help confirm lung diseases, such as asthma and chronic obstructive lung disease (COPD). They are also useful for monitoring the progression of lung disease or evaluating the risk of surgery in the preoperative patients (ATS Committee on Proficiency Standards for Clinical Pulmonary Function Laboratories, 2002; American Thoracic Society, 1995; Crapo, 1994; Hughes & Pride, 1999; Hyatt, Scanlon, & Nakamura, 1997).
Pulmonary function tests include spirometry and the quantitation of lung volume and diffusing capacity. Spirometry is in widespread use, because it takes 10–15 min without any risk. It measures mainly forced expiratory volume in 1 s (FEV1.0) and forced vital capacity...