Abstract Compliance is defined as the change in lung volume produced by a unit change in transpulmonary pressure. Lung compliance is represented by the gradient of the pressure–volume curve. Chapter…

Abstract The O2 cascade concept draws together areas of respiratory physiology covered in the previous few chapters. In an examination setting, it allows the examiner to assess your knowledge of…

Abstract The partial pressure gradient of O2 between the alveolus and the pulmonary capillaries is one of the key factors that determine the rate of O2 diffusion across the alveolar–capillary…

Abstract Global O2 consumption V̇O2 (mL/min) is the volume of O2 that is consumed by the body per minute. Chapter 17 Oxygen Delivery and Demand What is meant by the…

Abstract Hypoxia refers specifically to the situation in which tissues are unable to undergo aerobic metabolism. Hypoxaemia refers specifically to reduced PaO2. This can result from either a failure of…

Abstract In the upright position, ventilation and perfusion both increase from the top to the bottom of the lung. This was previously attributed to the effect of gravity (the so-called…

Abstract Lung perfusion1 increases linearly from the top to the bottom of the lungs (Figure 15.1, lung perfusion line). The difference in perfusion at the top and bottom of the…

Abstract Alveolar volume VA, the volume of air which reaches perfused alveoli. Chapter 11 Ventilation and Dead Space In the lungs, what is meant by the term ‘dead space’? The…

Abstract Pulmonary function tests (PFTs) are used to quantify an individual patient’s respiratory physiology. A battery of tests and manoeuvres are performed to measure the performance of the different lung…

Abstract A lung volume is measured directly, by a spirometer (Figure 12.1) or by a gas dilution technique (see p. ). A lung capacity is the sum of two or…