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Ventilation is wasted, as it fails to oxygenate any blood. A high V/Q can also be observed in emphysema as a maladaptive ventilatory overwork of the undamaged lung parenchyma. Because of the loss of alveolar surface area, there is proportionally more ventilation per available perfusion area.
Alveolar gas volume: V L: ... The spirometry test is performed using a device called a spirometer, [2] ... Maximum voluntary ventilation (MVV) is a measure of the ...
A ventilation perfusion scan or lung scintigraphy can be used to diagnose areas of lungs being ventilated but not adequately perfused. This results in a raised Alveolar-arterial (A-a) gradient which is responsive to supplemental oxygen. In conditions with right to left shunts, there are also ventilation perfusion defects with high A-a gradients.
The Alveolar–arterial gradient (A-aO 2, [1] or A–a gradient), is a measure of the difference between the alveolar concentration (A) of oxygen and the arterial (a) concentration of oxygen. It is a useful parameter for narrowing the differential diagnosis of hypoxemia. [2] The A–a gradient helps to assess the integrity of the alveolar ...
Positive end-expiratory pressure (PEEP) is the pressure in the lungs (alveolar pressure) above atmospheric pressure (the pressure outside of the body) that exists at the end of expiration. [1] The two types of PEEP are extrinsic PEEP (PEEP applied by a ventilator) and intrinsic PEEP (PEEP caused by an incomplete exhalation).
When observing a collection of alveoli in which PO 2 and PCO 2 are uniform, local alveolar ventilation and local blood flow define / : V A = Q × V A / Q {\displaystyle V_{A}=Q\times V_{A}/Q} From these equations it can be deduced that to have knowledge of either retention or excretion implies knowledge of the other.
Minute ventilation (or respiratory minute volume or minute volume) is the volume of gas inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs per minute. It is an important parameter in respiratory medicine due to its relationship with blood carbon dioxide levels .
A spirometer measures ventilation, the movement of air into and out of the lungs. The spirogram will identify two different types of abnormal ventilation patterns, obstructive and restrictive. There are various types of spirometers that use a number of different methods for measurement (pressure transducers, ultrasonic, water gauge).