A spirometer is an apparatus for measuring the volume of air inspired and expired by the lungs. A spirometer measures ventilation, the movement of air into and out of the lungs. The spirogram will identify two different types of abnormal ventilation patterns, obstructive and restrictive. There are various types of spirometers that use a number of different methods for measurement (pressure transducers, ultrasonic, water gauge).
Pulmonary function tests
A spirometer is the main piece of equipment used for basic Pulmonary Function Tests (PFTs). Lung diseases such as asthma, bronchitis, and emphysema may be ruled out from the tests. In addition, a spirometer often is used for finding the cause of shortness of breath, assessing the effect of contaminants on lung function, the effect of medication, and evaluating progress for disease treatment.
Reasons for testing Diagnose certain types of lung disease (such as COVID-19, bronchitis, and emphysema) Find the cause of shortness of breath Measure whether exposure to chemicals at work affects lung function Check lung function before someone has surgery Assess the effect of medication Measure progress in disease treatment
History
Early development The earliest attempt to measure lung volume can be dated back to the period A.D. 129–200. Claudius Galen, a Roman physician and philosopher, did a volumetric experiment on human ventilation. He had a child breathe in and out of a bladder and found that the volume did not change. The experiment proved inconclusive.
1681, Giovanni Alfonso Borelli tried to measure the volume of air inspired in one breath. He assembled a cylindrical tube partially filled with water, with an open water source entering the bottom of the cylinder. He occluded his nostrils, inhaled through an outlet at the top of the cylinder and measured the volume of air displaced by water. Nowadays, this technique is very important in determining parameters of lung volume.
Nineteenth century 1813, Edward Kentish used a simple "Pulmometer" to study the effect of diseases on pulmonary lung volume. He used an inverted graduated bell jar standing in water, with an outlet at the top of the bell jar controlled by a tap. The volume of air was measured in units of pints. 1831, Charles Thackrah described a "Pulmometer" similar to that of Kentish. He portrayed the device as a bell jar with an opening for the air to enter from below. There was no correction for pressure. Therefore, the spirometer not only measured the respiratory volume, but also the strength of the respiratory muscles. 1845, Karl von Vierordt in his book entitled "Physiologie des Athmens mit besonderer Rücksicht auf die Auscheidung der Kohlensäure" discussed his interest in measuring the volume of expiration accurately. He also completed accurate measures of other volume parameters by using his "Expirator". Some of the parameters he described are used today, including residual volume and vital capacity. 1846 The water spirometer measuring vital capacity was developed by a surgeon named John Hutchinson. He invented a calibrated bell inverted in water, which was used to capture the volume of air exhaled by a person. Hutchinson published his paper about his water spirometer and the measurements he had taken from more than 4,000 subjects, describing the direct relationship between vital capacity and height and the inverse relationship between vital capacity and age. He also showed that vital capacity does not relate to weight at any given height. Hutchinson is regarded as the inventor of vital capacity because he found that with every inch of height vital capacity increased by eight cubic inches. He also used his machine for the prediction of premature mortality. He coined the term 'vital capacity', which was claimed as a powerful prognosis for heart disease by the Framingham study. He believed that his machine should be used for actuarial predictions for companies selling life insurance. 1854 Dr. M. Alton Wintrich developed a spirometer, which was easier to use than Hutchinson's. He did an experiment with 4,000 subjects and concluded that there are three parameters affecting vital capacity: height, weight, and age. His experiment produced results similar to those of Hutchinson's study. 1859 E. Smith developed a portable spirometer, which he used to measure gas metabolism. 1866 Henry Hyde Salter (1823-1871) added a kymograph to the spirometer in order to record time while obtaining air volumes. 1879 Gad J. published a paper entitled "Pneumatograph" that described a machine that allowed the recording of lung volume changes.
Twentieth century 1902, Brodie T. G. was the first to use a dry-bellowed wedge spirometer 1904 Tissot introduced the closed-circuit spirometer 1939 Compton S. D. developed the lungometer for use by Nazi Germany 1959 Wright B. M. and McKerrow C. B. introduced the peak flow meter 1969 DuBois A. B. and van de Woestijne K. P. experimented on humans using the whole body plethysmograph 1974 Campbell et al. refined the previous peak flow meter, developing a cheaper and lighter version
… excerpt ends here. Continue reading the full article.
