JPP Letters

Dear Editor,

I read with interest the article by Matthews (2018) detailing the function and use of pulse oximetry technology. I would question Matthews' assertion that the Milliken Oximeter in 1940, was the first true oximeter. While Milliken is probably the father of clinical oximetry, it must be acknowledged that his work owed a lot to the work of a number of German scientists in the 1930s who demonstrated colour change of haemoglobin when oxygenated or deoxygenated, and constructed the first device which applied two wavelengths of light to the earlobe to demonstrate the oxygen saturation levels of a human subject (Severinghaus and Astrup, 1986).

I would also like to expand slightly on Matthews' work with some brief points which may further the understanding of paramedics in relation to the physics behind the pulse oximeter and help them anticipate causes of spurious readings in their clinical practice.