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Takuo Aoyagi (1936–2020), pulse oximeter inventor

by Linnea Crowther

Takuo Aoyagi was a Japanese engineer who developed technology that made the modern pulse oximeter possible, allowing us to measure the level of oxygen in the blood.

Improving on a flawed design

Aoyagi was working for medical equipment company Nihon Kohden in the 1970s when he began working on the science behind pulse oximetry. Earlier devices had been developed, but they were clunky and inaccurate. Aoyagi’s innovation was a technology that eliminated the noise made by pulsing blood, which allowed the oxygen level to be read clearly and easily. Along with a colleague who developed the pilot model, Aoyagi held the patent as co-inventor of the pulse oximeter. Their design became the standard for the device that is still used today.

A crucial tool in the COVID-19 fight

The pulse oximeter has become a commonplace device, used in hospitals and clinics around the world, and the blood oxygen level is now one of the basic vital signs taken by medical professionals along with blood pressure, pulse, respiratory rate, and temperature. Blood oxygen level is now more important than ever as we combat COVID-19. The medical community has found that patients who appear to have mild to moderate symptoms can have a dangerously low blood oxygen level, which can lead to severe complications. Some patients who have been tested for the novel coronavirus are now sent home with a pulse oximeter to keep an eye on their blood oxygen level as they recuperate.


What people said about him

Full obituary: The New York Times

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