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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

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.
Farlex Partner Medical Dictionary © Farlex 2012

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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
* [FEF.sub.2-20] Mean forced expiratory flow rate between 2 to 1.2 litres of volume change.
Forced expiratory flow 25 (FEF 25): This is the instantaneous flow rate at the point when 25% of FVC has been exhaled.
In children, the forced expiratory flow over the middle half of forced vital capacity, or FEF25%-75%, is a more sensitive indicator of airflow obstruction than is [FEV.sub.1], he said.
Pulmonary function testing showed a mild obstructive defect primarily affecting the small airways: forced vital capacity (FVC), 94%; forced expiratory volume in 1 sec (FE[V.sub.1]), 79%; and forced expiratory flow rate over the middle 50% of the FVC volume (FE[F.sub.25%-75%]), 51%.
The instrument records several parameters such as FVC, FEV1, FEV1/FVC%, forced expiratory time (FET), peak expiratory flow rate (PEFR), forced inspiratory flow at 50% of inspired volume during FVC test (FIF50%), forced expiratory flow at 50% of expired volume during FVC test (FEF50%), and peak inspiratory flow rate (PIFR) digitally in variable seconds and as percentages besides providing a computer recorded tracing.
A relatively small reduction in the annum average exposure to particulate matter with an aerodynamic diameter under 10 mcm ([PM.sub.10]) decreased the annual decline in forced expiratory flow between 25% and 75% of the forced vital capacity (FEF.sub.25.75]) by 22%, they reported.
Aims and Objective: The aim is to study correlation of body mass index (BMI) and flow rates (forced expiratory flow 25-75% [FEF 25-75%], FEF 75%, peek expiratory flow [PEF], and maximum voluntary ventilation [MVV]) of pulmonary function test in controls and patients.
95%; and forced expiratory flow at 25%-75% of forced vital capacity (FE[F.sub.25%-75%]), 72% vs.
The mean of experimental group of forced vital capacity (FVC) was 2.2366 [+ or -] 0.59186, forced expiratory volume in 1 s (FEV1) was 1.7594 [+ or -] 0.51072, FEV1/FVC was 0.79 [+ or -] 0.13, forced expiratory flow in 25-75% (FEF 25-75%) was 1.756 [+ or -] 0.93667, peak expiratory flow rate (PEF) was 4.1528 [+ or -] 1.45828, FIVC was 1.7936 [+ or -] 0.95744, and PIF was 2.1346 [+ or -] 1.35958 were significantly lower when compared with the control group.
Strunk reported that analyses of secondary outcome measures showed benefit in the forced expiratory flow during the middle half of the forced expiratory capacity ([FEF.sub.25%-75%]), the ratio of forced expiratory volume in 1 second ([FEV.sub.1]) to forced vital capacity (FVC), and the ratio of [FEF.sub.25%-75%] to FVC.
* Spirometric using SpiroLab III in setting position with closed nose and the test repeated 15 min after nebulization with 5 mg salbutamol solution, and 3 parameters were selected FVC, FEV1 to measure the ratio FEV1/FVC and forced expiratory flow (FEF) 50 as a reflection to small airway disease and all patient with reversibility <12% were selected for more evaluation.
Children with a history of croup or recurrent croup also had a lower mean percentage of predicted forced expiratory flow at both 50% and 75% of forced vital capacity than children without such a history.

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