MMEF = FVC/(2*MET)

English Name: Maximum Mid-Expiratory Flow, MMEF

Normal Range: Male: (3452±1160)ml/s; Female: (2836±946)ml/s

MMEF is the average flow rate of 25%-75% of the forced vital capacity. It is a sensitive indicator for detecting the impact of air pollution on small airway function. The maximum ventilation can reflect the severity of airway obstruction, as well as the patient's respiratory reserve, muscle strength, and dynamic level. It can be used for preoperative evaluation. Decreases are seen in: (1) Increased airway resistance: such as various chronic obstructive pulmonary diseases, bronchial asthma, or bronchial tumors. (2) Lung tissue damage: such as pneumonia, tuberculosis, alveolar hemorrhage, pulmonary edema, interstitial fibrosis. (3) Thoracic and pleural diseases: such as severe scoliosis, rib fractures, pneumothorax, large pleural effusion. (4) Nervous system and respiratory muscle activity disorders: such as anesthesia, encephalitis, poliomyelitis, and myasthenia gravis.