In 1940, J.R. Squire was the first to recognize that the differences in transmission of red and infrared light permitted oxygen saturation to be computed. In 1942, the British scientist Glen Millikan developed the first portable pulse oximeter to be used during pilot training in World War II. The device was placed on the earlobe and was used to monitor pilots’ oxygen saturation and safety during flight.
Thirty years later in 1972, the Japanese bioengineer Takuo Aoyagi developed conventional pulse oximetry by using the ratio of red to infrared light absorption in pulsating (arterial) blood to calculate oxygen saturation. This was later commercialized and gradually integrated into clinical practice in the 1980s and 1990s. Notably, the American Society of Anesthesiologists determined in 1986 that using pulse oximetry was to be recognized as the new standard of care. To learn more history about the development of the pulse oximeter, read here.
References: Severinghaus et al, J Clin Monit 1986; Millikan, Rev Sci Instrum 1942; Severinghaus, Anesth Analg 2007, Wood Library Museum of Anesthesiology
Keywords: first, invention, Millikan, Aoyagi