What is mid expiratory flow?
The mid maximum expiratory flow (MMEF) is obtained by drawing the chord across the middle half of the vital capacity and dividing the volume by the time. It may be related to the tangent to the curve at 50 per cent point which is V ˙ 50 (see text)
What is a normal FEF 25 75?
In particular, FEF25-75% was categorized as (1) <65% of predicted or <-1.64 z-score (abnormal values) or (2) >65% of predicted or between -1.64 and +1.64 z-score (normal values) [23].
What is maximal mid expiratory flow?
Background. The maximal expiratory flow at 50 % of the forced vital capacity (MEF50) is the flow where half of forced vital capacity (FVC) remains to be exhaled. A reduced MEF50 has been suggested as a surrogate marker of small airways disease.
What is MMEF in lung function?
Maximum mid-expiratory flow The MMEF is the mean forced expiratory flow between 25% and 75% of the FVC (FEF25%–75%) and is taken from the spirometric blow with the largest sum of FEV1 and FVC. The MMEF is highly dependent on the validity of the FVC measurement and the level of expiratory effort.
How is FEV measured?
FEV is short for forced expiratory volume. FEV1 is the amount of air you can force from your lungs in one second. It’s measured during a spirometry test, also known as a pulmonary function test, which involves forcefully breathing out into a mouthpiece connected to a spirometer machine.
What is FET in spirometry?
Forced expiratory time (FET) as an indicator for airways obstruction.
What is MEF spirometry?
MMEF or MEF stands for maximal (mid-)expiratory flow and is the peak of expiratory flow as taken from the flow-volume curve and measured in liters per second. It should theoretically be identical to peak expiratory flow (PEF), which is, however, generally measured by a peak flow meter and given in liters per minute.
What can affect lung capacity?
Conclusions. Physiological factors that influence lung volumes/capacities include age, gender, weight, height and ethnicity, physical activity, altitude and others, which should be considered while interpreting results of spirometry.