Recently, the world lost a great pioneer in the field of medical technology.
Takuo Aoyagi was a Japanese engineer who dedicated much of his life to medical research and development. After over half a century of contributions to the medical field, Mr. Aoyagi died at the age of 84.
He was known for his groundbreaking invention of a medical device called the modern pulse oximeter. A pulse oximeter is a small electronic device that clips onto one’s finger and can measure the amount of oxygen in their blood. This life-saving invention is a vital tool currently being used in the coronavirus pandemic.
Over his lifetime, Mr. Aoyagi achieved many milestones in the field of medicine. His research of modern pulse oximetry earned him awards like the IEEE Medal for Innovations in Healthcare Technology and a Medal with Purple Ribbon from the Emperor of Japan.
The Science Behind the Pulse Oximeter
The level of oxygen in one’s blood is known as oxygen saturation. It is calculated by measuring the amount of oxygenated blood (blood carrying oxygen from the lungs) compared to deoxygenated blood (blood carrying carbon-di-oxide back to the lungs).
Pulse oximetry uses beams of light to detect oxygen levels. The pulse oximeter resembles a clip with two types of light sent from one side to the other. When a finger is placed between the clip, a certain amount of the light is absorbed by the finger.
The amount of light absorbed depends on the characteristics of a person’s blood. Blood with sufficient oxygen absorbs more of infrared light. Meanwhile, blood with low oxygen absorbs more of red light.
Based on how much of each type of light is absorbed, the pulse oximeter displays the oxygen saturation of the patient’s blood.
A pulse oximeter is commonly used to test oxygen levels in blood in people with certain conditions or before/after medical procedures.
Most people need oxygen saturation levels of 90% or above for their cells to be healthy. This device can help health providers decide if a patient needs more oxygen in their blood or a ventilator.
The pulse oximeter has been of much help during the coronavirus crisis. One of the main symptoms of COVID-19 is low blood oxygen levels or hypoxemia. However, this symptom is almost unnoticeable by humans. Thanks to the pulse oximeter, people have an accessible way to test for this symptom without having to go to the hospital.
Sources: NYTimes, NPR, hopkinsmedicine.org, CNN, howequipmentworks.com