Measurements of ventilation Flashcards
Tidal volume (TV)
-the amount of air inhaled and exhaled in one respiratory cycle under normal conditions
inspiratory reserve volume (IRV)
amount of air that can be forcefully inhaled after a normal TV inhalation
expiratory reserve volume (ERV)
amount of air that can be forcefully exhaled after a normal TV exhalation
residual volume (RV)
amount of air left in the lungs after maximal exhalation
*usually estimated
* cannot completely empty lungs
respiratory capacities
-calculated from respiratory volumes (two or more volumes added together)
vital capacities (VC)
-the maximal amount of air that can be exhaled after a maximal inspiration
-not the same for men and women
men: 2.5 L/m2 of body surface area
women: 2.0 L/m2 of body surface area
-in diseases such as pneumonia or emphysema a decrease in FVC may be noted, also tumors or enlarged blood vessels also decrease lung space
-also decreases with age
Inspiratory Capacities (IC)
-the maximum amount of air that can be inhaled after a normal expiration
functional residual capacity (FRC)
-the amount of air remaining in the lungs after a normal expiration
Total lung capacity (TLC)
the maximum amount of air the lungs can hold
respiratory rate (RR)
amount of normal respiratory cycles (inhalation and exhalation) that occur in one minute (60sec) typically 12-20 resps/min) at rest
Minute respiratory volume (MRV)
-amount of air inhaled in one minute under normal resting conditions typically 6000-10,000 mL/min (6-10 L/min)
Maximum voluntary ventilation (MVV) or maximum breathing capacity
the maximum amount of air inhaled in one minute during physical activity as high as 125,000-170,000 mL/min (125-170 L/min)
forced vital capacity (FVC)
-the amount of air exhaled when a deep breath is taken and then forcefully exhaled as much as possible (usually released in a period of 6-7 sec)
-average is 4800 ml or 4.8 L
forced expiratory volume (FEV)
-the amount of air expelled during specific time intervals of the FCV
FEV1, FEV2, FEV3 (etc)
-amount of air exhaled during the first, second, third, etc, second respectively of the FVC (measured as a percentage)
-looks at slope, how fast you can get to max
-75-78% is normal for FEV1
