(redirected from spirometer)
Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to spirometer: Incentive spirometer


The measurement, by a form of gas meter, of volumes of gas that can be moved in or out of the lungs. The classical spirometer is a hollow cylinder (bell) closed at its top. With its open end immersed in a larger cylinder filled with water, it is suspended by a chain running over a pulley and attached to a counterweight. The magnitude of a gas volume entering or leaving is proportional to the vertical excursion of the bell. Volume changes can also be determined from measurements of flow, or rate of volume change, that can be sensed and recorded continuously by a transducer that generates an electrical signal. The flow signal can be continuously integrated to yield a volume trace.

The volume of gas moved in or out with each breath is the tidal volume; the maximal possible value is the vital capacity. Even after the most complete expiration, a volume of gas that cannot be measured by the above methods, that is, the residual volume, remains in the lungs. It is usually measured by a gas dilution method or by an instrument that measures blood flow in the lungs. Lung volumes can also be estimated by radiological or optical methods.

At the end of an expiration during normal resting breathing, the muscles of breathing are minimally active. Passive (elastic and gravitational) forces of the lungs balance those of the chest wall. In this state the volume of gas in the lungs is the functional residual capacity or relaxation volume. Displacement from this volume requires energy from natural (breathing muscles) or artificial (mechanical) sources. See Respiration



the measurement of the breathing capacity of the lungs. Spirometry was introduced in 1846 by the English scientist J. Hutchison.

Breathing capacity comprises the resting tidal volume of air that moves in and out of the lungs with each breath (approximately 500 cc), the inspiratory reserve volume of air that enters the lungs with maximal inhalation (approximately 1,500 cc), and the expiratory reserve volume of air that emerges from the lungs with maximal exhalation after normal exhalation (approximately 1,600 cc).

The breathing capacity of the lungs is usually measured with a spirometer (see Figure 1), which consists of a water-filled cylindrical tank that contains a floating cylindrical bell (1). The bell is

Figure 1

open at the bottom end and balanced by two counterweights. A rubber connecting tube (2) passes beneath the bottom of the bell. When a person forcefully exhales into the tube after taking a deep breath, the exhaled air forces the interior cylinder to rise. The volume of exhaled air is measured in cm3 according to a calibrated scale (3). Air is released from the spirometer by turning a valve (4).

The spirometer is used in examining healthy persons and in diagnosing and treating diseases of the lungs and cardiovascular system. In recent years spirographs have also been used to measure breathing capacity. Respiratory movements are recorded on spirograms, and breathing capacity is calculated according to special tables.



The measurement, by a form of gas meter (spirometer), of volumes of air that can be moved in or out of the lungs.
Mentioned in ?
References in periodicals archive ?
The report covers the present scenario and the growth prospects of the global spirometer market for 2016-2020.
Between subjects, volume-based spirometers used with a closed-circuit technique should be flushed with room air at least 5 times over the spirometer's entire volume range to ensure clearance of droplet nuclei.
Independent patients received an incentive spirometer (Voldyne[R] 5000 Volumetric Exeroser, Hudson RCI [Research Triangle Park, NC]) and an oral care packet of toothbrush and toothpaste.
A surprising result was that even though subjects used the spirometer during game play and the control period, their ability to take a deep breath (termed vital capacity) improved significantly only after game play.
It's essentially a mini spirometer, a device used to measure the functioning of the lungs.
How the test works Each case study was asked to blow into a spirometer.
Patients with suspected conditions such as asthma or Chronic Obstructive Pulmonary Disease breathe into the spirometer to assess how well their lungs work.
Their unique design allows for low resistance and minimizes dead space, preserving the accuracy of your spirometer.
His patients and their parents went home with a conventional spirometer for at-home testing of the volume and velocity of airflow from the children's transplanted lungs.
Among recipients was Marske Medical Centre, which received a pounds 1,000 spirometer.
A spirometer thoughtfully designed for office use would be smaller, cheaper, easier to use, easier to run and calibrate, and more reliable.
The study also measured lung function by using a spirometer, a test which measures the volume of air a patient can exhale from the lungs.