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The respiratory quotient (RQ or respiratory coefficient) is a dimensionless number used in calculations of basal metabolic rate (BMR) when estimated from carbon dioxide production. It is calculated from the ratio of carbon dioxide produced by the body to oxygen consumed by the body, when the body is in a steady state.
The Shunt equation (also known as the Berggren equation) quantifies the extent to which venous blood bypasses oxygenation in the capillaries of the lung.. “Shunt” and “dead space“ are terms used to describe conditions where either blood flow or ventilation do not interact with each other in the lung, as they should for efficient gas exchange to take place.
Measurement of PEFR requires training to correctly use a meter and the normal expected value depends on the patient's sex, age, and height. It is classically reduced in obstructive lung disorders such as asthma. Due to the wide range of 'normal' values and the high degree of variability, peak flow is not the recommended test to identify asthma.
A pulmonary shunt is the passage of deoxygenated blood from the right side of the heart to the left without participation in gas exchange in the pulmonary capillaries. It is a pathological condition that results when the alveoli of parts of the lungs are perfused with blood as normal, but ventilation (the supply of air) fails to supply the perfused region.
where RQ is the respiratory quotient (ratio of volume CO 2 produced to volume of O 2 consumed), is 21.13 kilojoules (5.05 kcal), the heat released per litre of oxygen by the oxidation of carbohydrate, and is 19.62 kilojoules (4.69 kcal), the value for fat. This gives the same result as the Weir formula at RQ = 1 (burning only carbohydrates ...
Bronchoalveolar lavage (BAL), also known as bronchoalveolar washing, is a diagnostic method of the lower respiratory system in which a bronchoscope is passed through the mouth or nose into an appropriate airway in the lungs, with a measured amount of fluid introduced and then collected for examination.
Lung volumes. Functional residual capacity (FRC) is the volume of air present in the lungs at the end of passive expiration. [1] At FRC, the opposing elastic recoil forces of the lungs and chest wall are in equilibrium and there is no exertion by the diaphragm or other respiratory muscles.
In respiratory physiology, the ventilation/perfusion ratio (V/Q ratio) is a ratio used to assess the efficiency and adequacy of the ventilation-perfusion coupling and thus the matching of two variables: V – ventilation – the air that reaches the alveoli; Q – perfusion – the blood that reaches the alveoli via the capillaries