Takuo Aoyagi
Takuo Aoyagi was a Japanese engineer, known for his work leading to the modern pulse oximeter.
Early life, education and career
Aoyagi was born February 14, 1936, in Niigata Prefecture, Japan. His parents were Monshichi and Tatsu Aoyagi. His father was a mathematics teacher and his mother was a homemaker.Aoyagi received an undergraduate degree in electrical engineering from Niigata University in 1958. He then worked for a time for the scientific instrumentation company Shimadzu Corporation, before moving to the research division of the medical equipment company Nihon Kohden in 1971.
Pulse oximetry
An earlier oximeter had been invented by Glen Millikan, building on work by Karl von Vierordt, Karl Matthes, and others. Earl Wood and his PhD student J. E. Geraci made some improvements. These early devices were inaccurate and difficult to use. The main idea was to measure the difference in how blood absorbed red light versus infrared light.An obstacle was that the pulse of blood created a great deal of noise. Early devices tried to work around this by limiting measurement to the ear, and with other methods. Shortly after starting at Nihon Kohden in 1971, Aoyagi showed how to remove the noise from the measurement, leading to a practical and accurate measurement of oxygen in the blood. Similar ideas were developed slightly later by Masaichiro Konishi and Akio Yamanishi of Minolta.
Nihon Kohden submitted an application for a patent on the resulting device in 1974, which named Aoyagi and his colleague Michio Kishi as co-inventors. The patent was granted in 1979.
In 2007, World Health Organization listed pulse oximeter as an essential device for Surgical Safety Checklist for Patient.