Diuresis
Removing excess fluid from the body through increased urine output.

Dyspnea
Shortness of breath.

Dysplasia
Formation of abnormal tissue.

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Emphysema
Is a chronic obstructive lung disease that destroys alveoli walls.  The alveoli can be compared to a balloon that has been blown up and the air has been let out.  It no longer snaps back into place when stretched but lies floppy.  When fresh air enters a lung with emphysema, it enters the alveoli because of changes in pressure.   The fresh air now in the alveoli should give off oxygen and take on carbon dioxide to exhale and rid it from the body.  However, instead of being exhaled, the air becomes trapped and unable to be pushed out because of the lack of elasticity of the alveoli.  Stale air mixes with fresh air on the next breath.  Emphysema is most commonly caused by smoking.  A genetic form called alpha 1-antitrypysin deficiency emphysema is caused by the lack of an enzyme.  This emphysema strikes at a younger age (by 35 in those who smoke; in the 40s in a nonsmoker) than the emphysema caused by smoking (usually by 60s).

Endotracheal tube
Ventilating tube inserted through the stoma (opening) created  by the surgical process of fenestration (cutting a window–like opening, a  fenestra), in the anterior (front side) of the trachea (a trachesotomy).

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Fenestra
A circular window–like opening.

Fenestration
The surgical creation of a circular window–like opening (a fenestra).

Fibrosis (adj. fibrotic)
The formation of restrictive fibrous tissue (scarring) in a structure such as the lungs that may compromise the normal functioning of the structure to varying degrees from relative insignificant compromise (small if any impact on normal day to day living) to severe compromise (perhaps requiring use of oxygen for the rest the life).  Although usually irreversible in nature, some improvement may occur within usually the first 6 to 12 months after the precipitating event.  Generally, a plateau is usually reached at that point, although some improvement may continue to be experienced in a small number of persons for longer periods of time.  Pulmonary rehabilitation (an article on Pulmonary Rehab is available in our Learn About ARDS Section 1) may provide significant benefits in assisting an individual to live as normal a life as possible with the resulting permanent structural change.  See Pulmonary Fibrosis.

Flow control
Mechanical ventilator control that regulates the rate at which air is passed through the lungs.

Flow Rate Values
Speed at which air moves through the lung.

Foot drop
A neurological problem that causes walking and gait problems.

Forced Expiratory Volume in One Second (FEV1)
Is a measurement of flow rate; this is the amount of air that can be exhaled in the first second after you take the deepest breath that you can. In obstructive lung disease, this measurement is as basic as taking your temperature. You should know what your FEV1 is on a normal day. Asthmatics who take their FEV1 with a peak flowmeter on a daily basis can tell when an attack is beginning before the person even feels symptoms.

Fraction of inspired oxygen (FiO2)
The percentage of oxygen in the air inhaled, either on or off the ventilator. FiO2 ranges are from 21% (e.g. in room air) to 100% (e.g. pure oxygen).

Functional residual capacity (FRC)
The volume of gas that remains in the lungs after the exhalation of a spontaneous or mechanically assisted breath. Infants with surfactant deficiency have a lower FRC.

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