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Device for spirometry. The patient places his or her lips around the blue mouthpiece. The teeth go between the nubs and the shield, and the lips go over the shield. A nose clip guarantees that breath will flow only through the mouth. Screen for spirometry readouts at right. The chamber can also be used for body plethysmography.
The interpretation of tests depends on comparing the patients values to published normals from previous studies. Deviation from guidelines can result in false-positive or false negative test results, even though only a small minority of pulmonary function laboratories followed published guidelines for spirometry, lung volumes and diffusing ...
To interpret the significance of peak expiratory flow measurements, a comparison is made to reference (normal, predicted) values based on measurements taken from the general population. Various reference values have been published in the literature and vary by population, ethnic group, age, sex, height and weight of the patient.
A normal adult has a vital capacity between 3 and 5 litres. [3] A human's vital capacity depends on age, sex, height, mass, and possibly ethnicity. [ 4 ] However, the dependence on ethnicity is poorly understood or defined, as it was first established by studying black slaves in the 19th century [ 5 ] and may be the result of conflation with ...
The average total lung capacity of an adult human male is about 6 litres of air. [1] Tidal breathing is normal, resting breathing; the tidal volume is the volume of air that is inhaled or exhaled in only a single such breath. The average human respiratory rate is 30–60 breaths per minute at birth, [2] decreasing to 12–20 breaths per minute ...
This test involves measuring the partial pressure difference between inspired and expired carbon monoxide. It relies on the strong affinity and large absorption capacity of red blood cells for carbon monoxide and thus demonstrates gas uptake by the capillaries that are less dependent on cardiac output. [3]
Preconceived notions that 'white' people have greater pulmonary function are embedded in spirometer measurement interpretation and have only been reinforced through this medical stereotyping. In the United States, spirometers use correction factors of 10-15% for those identified as 'black' and 4-6% for those identified as 'Asian.' [ 6 ]
TLC: Total lung capacity: the volume in the lungs at maximal inflation, the sum of VC and RV. TV: Tidal volume: that volume of air moved into or out of the lungs in 1 breath (TV indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol TV or V T is used.)