A previous “Retrospectroscope” note dealt with spirometry: it described many apparatuses used to measure the volume of inhaled and exhaled air that results from breathing. Such machines, when adequately modified, are also able to measure the rate at which work is produced.
In Latin, spirare means to breathe, hence, spirometry deals with the measurement of breath, which is the most common way to evaluate pulmonary function. Volume or flow of inhaled or exhaled air is so quantified offering values that permit an assessment of respiratory performance in health and disease. Asthma, emphysema, pulmonary fibrosis, obstructive lung pathologies can be gauged in their respective stages. It is an old procedure, still in use, simple and inexpensive, but highly significant in health care.