Spirometry


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Spirometry

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

Spirometry

 

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.

V. F. POZHARISKII

spirometry

[spī′räm·ə·trē]
(physiology)
The measurement, by a form of gas meter (spirometer), of volumes of air that can be moved in or out of the lungs.
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Participants were randomly (1:1) assigned to spirometry either with the mobile spirometer connected to a smartphone or the desktop spirometer first, followed by the other.
* A difference in spirometry findings pre- and post-operatively.
Respiratory diseases are responsible for the global increase in morbidity and mortality, especially among children and adolescents.1 Focussing on the developing countries like Pakistan, the 2012 report of the World Health Organisation (WHO) showed that 34% of Pakistani population was under 15 years of age with high prevalence of respiratory diseases.2 To diagnose these diseases, different pulmonary function tests are used and among them the spirometry is the gold standard one.3 Spirometry does not require either a complicated technique or the instrument and is a non-invasive procedure as well.
I think that the frontiers of this area are going to be to incorporate new elements such as tobacco history, more emphasis on clinical signs and symptoms, and use of markers other than spirometry, such as eosinophil count, to categorize patients with COPD," Dr.
Some of the studies report the differences in spirometry lung function of white children and adolescents to those of Asians specifically the south Asians5-8, the reason for this difference may be the genetic factor5,9, it may be the anthropometric differences10-15, may be ethnicity5,8,16,17, or it may be the environmental factor like cultural factors, the socioeconomic status6,18-24 or the chemical exposure.25-27 So there is a need to keep up-to-date reference data.
Spirometry was performed in all the patients in the chest OPD, College of Medicine and Sagore Dutta Hospital, Kamarhati using Spirolab III, Ver 3.7 SN 311909, manufactured by Cipla Company by trained technician at the beginning of the study.
KEY WORDS: Spirometry; Dyspnea; Pattern; Obstruction; Restriction.
Spirometry showing forced expiratory volume in one second ([FEV.sub.1]) and forced vital capacity (FVC) above 80% of predicted, according to Polgar et al.
GOLD had been moving toward symptoms and exacerbations to guide treatment for several years before formalizing the break from spirometry in its Nov.
[7,8] In addition, it is noticed that spirometry is rarely used for assessment of asthma control and adequacy of therapy for asthmatic patients under home management.
Citizens that fulfilled the recommendations for case finding for COPD issued by the Danish National Board of Health, that is, age >35 years, smokers/ex-smokers and/or relevant occupational exposure, and at least one respiratory symptom (dyspnea, cough, wheeze, sputum, and recurrent lower respiratory tract infections), were offered spirometry to investigate indications of obstruction.