History of Pulse Oximetry


Oximetry is the measurement of oxygen saturation in arterial by transmiting light through a translucent area of a patient. This is done noninvasively and the oxygen saturation level is computed based on the measurement. This device is responsible for saving thousands of lives each year.


Before pulse oximeter, the oxygen saturation was measured by a painful arterial blood gas and it typically took a minimum of 20-30 minutes to obtain the result. This delay is not acceptable as severe brain damage can occur within 5 minutes of low oxygenation. According to reports, 2,000 to 10,000 patients died because of undetected hypoxemia per year and there is no estimation of patient morbidity.


The following briefly outlines the development of this important device.


1864: Geory Gabriel Stokes discovered that hemoglobin is the oxygen carrier in blood.


1935: Matthes developed the first oxygen saturation meter. It used a 2-wavelength light source with red and green filters, whcih was later changed to red and infrared filters.


1941: "Oximetry testing" is first used to mesure oxygen saturation level with a pulse oximeter.


1940's: Millikan, a British scientist, used a dual light source to create the first practical aviation ear oxygen meter. During Second World War, many pilots were saved from under pressurized cabins by using oximetry testing.


1964: Hewlett Packard built the first ear oximeter by using eight wavelengths of light. The oximeter was used primary in sleep laboratories and in pulmonary functions. The unit was expensive, clumsy, and large.


1972: Takuo Aoyagi, a Japanese bioengineer at Nihon Kohden, developed a pulse oximeter based on the ratio of red to infrared light absorption in blood. He obtained a Japanese patent. Another Japanese research, Minolta, obtained an US patent based on the same concept. Oximetry became clinically feasible.


1981: Biox introduced the first commercial pulse oximeter. Initially it was focused on respiratory care and later expanded into operating rooms. Since then, other manufacturers have entered the market and the pulse oximeter technology has improved significantly.


1987: Pulse Oximetry becomes part of a standard procedure in administrating general anesthetic in US. The use of oximetry quickly spread to other hospital units, such as emergency rooms, recovery rooms, neonatal units, and intensive care units.


1995: Fingertip pulse oximeters first appeared on the market.


2000: Medicare accepted physicians´┐Ż billing for in-office oximeter readings.


2007: FDA published a notice in Federal Register (Vol. 72, No. 138 / Thursday, July 19, 2007) titled "Draft Guidance for Industry and Food and Drug Administration Staff; Pulse Oximeters Premarket Notification Submissions [510(k)s]; Availability" for comment by October, 2007. Shortly after, FDA approved pulse oximeters appeared on the market.


Recently: Pulse oximeter has become affordable and widely available for home use.