In Honor of Dr. Takuo Aoyagi: Pioneer of Pulse Oximetry Remembered

March 8, 2021

Pulse Oximeter

Dr. Takuo Aoyagi

Dr. Takuo Aoyagi

In the early 1970s, Takuo Aoyagi, Ph.D., an electrical engineer for the Nihon Kohden Company in Japan, discovered that pulsatile changes in oxygen saturation could be used to develop ratios of light absorption and compute pulse saturation. He understood the potential for his finding to improve patient care. He developed the technology and equipment for pulse oximetry and encouraged Nihon Kohden to provide the knowledge freely to companies worldwide. His efforts led to rapid development of improved equipment and adaptation of pulse oximetry into clinical practice.

Dr. Aoyagi passed away in 2020 at age 84. In his honor, the Japanese Society of Anesthesiologists is publishing a unique journal issue of 15 articles in 2021 that describe his work and the implications of pulse oximetry on patient safety. The American Society of Anesthesiologists will posthumously honor Dr. Aoyagi with honorary membership in October 2021. A 75-minute webinar on Dr. Aoyagi and his impact on patient safety was presented in February 2021 (

APSF will serve as an archive for English translations as well as the original articles in Japanese as soon as they are published in 2021. You can read more about Dr. Aoyagi at