forced expiratory flow
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Related to forced expiratory flow: forced expiratory volume
1. the movement of a liquid or gas.
2. the amount of a fluid that passes through an organ or part in a specified time; called also flow rate.
forced expiratory flow (FEF) the rate of airflow recorded in measurements of forced vital capacity, usually calculated as an average flow over a given portion of the expiratory curve; the portion between 25 and 75 per cent of forced vital capacity is called the maximal midexpiratory flow. Called also forced expiratory flow rate.
laminar flow smooth, uninterrupted flow as of a gas through a tube.
maximal expiratory flow FEF200–1200; the rate of airflow at forced vital capacity, represented graphically as the slope of the line connecting the points 200 mL and 1200 mL on the forced expiratory volume curve. See also pulmonary function tests. Called also maximal expiratory flow rate.
maximal midexpiratory flow FEF25–75; the maximum rate of airflow measured between expired volumes of 25 and 75 per cent of the vital capacity during a forced expiration; represented graphically as the slope of the line connecting the points on the forced expiratory volume curve at 25 and 75 per cent of the forced vital capacity. See also pulmonary function tests. Called also maximal midexpiratory flow rate.
renal plasma flow (RPF) the amount of plasma that perfuses the kidneys per unit time, approximately 90 per cent of the total constitutes the effective renal plasma flow, the portion that perfuses functional renal tissue such as the glomeruli.
turbulent flow flow that is agitated or haphazard.
forced ex·pi·ra·to·ry flow (FEF),
expiratory flow during measurement of forced vital capacity; subscripts specify the exact parameter measured, for example, peak instantaneous flow, the instantaneous flow at some specified point on the curve of volume expired versus time, or on the flow-volume curve, the mean flow between two expired volumes.
forced expiratory flow (FEF)
the average volumetric flow rate during any stated volume interval while a forced expired vital capacity test is performed. It is usually expressed as a percentage of vital capacity.
forced ex·pi·ra·to·ry flow(FEF) (fōrst eks-pī'ră-tōr-ē flō)
Expiratory flow during measurement of forced vital capacity; subscripts specify the exact parameter measured.