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Pulse Oximetry: A breath-taking historical view

As an anesthesiologist, my job is to keep patients alive and safe from surgical harm. The product I rely on most is a medical device called the pulse oximeter. This simple device clips onto a patient’s finger and measures the saturation of oxygen molecules bound to a patent’s hemoglobin, the protein responsible for carrying oxygen to bodily tissues and sustaining life. Today, it is easy to take this device for granted. After all, you can purchase a pulse oximeter on Amazon for less than $20. Yet the advent of the pulse oximeter in the late 1970s was a large reason why anesthesia-mortality risk has declined from about 1 death in 1000 surgical procedures in the 1940s to 1 in 10,000 in the 1970s and to 1 in 100,000 in the 1990s and early 2000s.

Why is this device so wonderful? Besides solving a critical unmet need (prior to pulse oximetry, anesthesiologists put their finger on a patient’s pulse and watched to see if the patient’s lips turned blue to see if they were asphyxiating), pulse oximetry is the epitome of the simplifying innovation. It converts a complex physiologic process (i.e. the differential absorption of light from the binding of oxygen and carbon dioxide to hemoglobin in pulsatile blood) into a simple percentage which is expressed both visually (numeric display) and aurally (a soothing beeping noise whose pitch varies based on the percentage saturation and rate varies based on the heart rate). It is used widely across almost all medical care settings from operating room to emergency room to doctor’s office to measure vital signs.

Pulse oximetry owes its origins to the anesthesiologists William New and Mark Yelderman of Stanford University Medical School. New recognized the potential importance of and market for a convenient, accurate oximeter in the operating room and all other hospital and clinic sites where patients are sedated, anesthetized, unconscious, comatose, paralyzed, or in some way limited in their ability to regulate their own oxygen supply. New, with engineer Jack Lloyd, founded Nellcor, which began the mass manufacture of the Nellcor pulse oximeters. The Nellcor pulse oximeter was evaluated by Yelderman and New, the manufacturers in 1983 [2. M. Yelderman and W. New, Jr., Evaluation of pulse-oximetry. Anesthesiology 59 (1983), pp. 349–352. View Record in Scopus | Cited By in Scopus (77)2].

After an initial period of skepticism, the Association of Anaesthetists of Great Britain and Ireland recognized the pulse oximeter as their standard for intraoperative monitoring in 1988, and 2 years later, the American Society of Anesthesiologists recognized it as their standard for intraoperative monitoring.

By 1993, there were about 40 companies making and selling pulse oximeters, and over 750 books, reviews, and papers concerning pulse oximetry were published. Nellcor was founded in 1981 and sold to Mallinckrodt (now Covidien) in 1995 for $2 billion.

The pulse oximeter revolutionized patient care in the operating room and in doing so, generated breath-taking clinical and commercial success.