Spirometry, derived from the Latin words SPIRO (to breathe) and METER (to measure), is a medical test which provides diagnostic information to assess a patient’s lung function.
The spirometer was originally invented in the 1840’s by John Hutchinson an English surgeon. The device (which was as tall as an adult patient) was essentially a calibrated bucket that was placed upside down in water. The volume of exhaled air from fully inflated lungs could accurately be measured by exhaling into a tube leading into the bucket. Dr. Hutchinson coined the term “vital capacity” i.e., capacity for life, when he realized that compromise of this crucial measurement was predictive for premature mortality. Because of the strong correlation between vital capacity and mortality, Hutchinson argued that it should be utilized in actuarial predictions for life insurance policies. Neither the spirometer nor its measurements were accepted by the insurance industry and the device was used primarily in a limited function to measure usable lung volumes in patients at tuberculosis sanitariums.
This changed around 1950 when it was determined that 90% of the predominant respiratory disorders (asthma and COPD) were obstructive (limited flow rate) in nature whereas vital capacity measured restriction. In 1950 Dr. Tiffeneau of France introduced the forced measurement of air volume during a given time frame, i.e., forced expiratory volume in 1 second, FEV1.
A published report by Drs. Stead and Wells determined that the classic water type spirometers of that era; although adequate for measuring lung volumes were not suitable for accurately measuring flow rates. It was clear that a different spirometer design was necessary. It was at this time that Jones Medical introduced the first available waterless spirometer providing an easier, more accurate, hygienic and affordable spirometer - marking a new era for widespread early detection of pulmonary disease at the physician office level.
In 1980 Hutchinson’s original premise was finally vindicated when upon review of the famous Framingham Study the Association of Life Insurance Medical Directors of America stated; “this simple office procedure is a useful predictor of pulmonary disease and cardiac failure and can effectively select groups of persons destined for premature death. Since the FVC predicts cardiovascular as well as non-cardiovascular mortality, this pulmonary function measurement seems truly a measure of living capacity useful for insurance and underwriting purposes.” Since then additional studies have also confirmed that spirometry is a better indicator of premature heart disease than any other single noninvasive test.
Although insurance companies still do not utilize spirometry to identify persons at high risk of premature mortality, the significance of spirometry for respiratory disease identification and management is no longer questioned. Today, a spirometer is the most valuable respiratory diagnostic tool available to health care providers. Spirometry is recommended in the practice guidelines for the diagnosis and management of both asthma and COPD. The FEV1 measurement is so important that it is the primary end point in clinical trials for nearly every respiratory drug approved today. Spirometry is also now required for Social Security/Disability evaluations, OSHA occupational respiratory surveillance and DOT physicals.
One of the greatest opportunities in medicine is the prevention or early identification of disease. Spirometry can identify airflow obstruction before COPD symptoms present and 5-10 years before signs appear on an X-ray.