Non-invasive multiwavelength photoplethysmography under low partial pressure of oxygen

Yung Chieh Fang, Cheng-Chi Tai

Research output: Contribution to journalArticlepeer-review


A reduction in partial pressure of oxygen in the environment may be caused by a gain in altitude, which reduces the atmospheric pressure; it may also be caused by the carbon dioxide generated from breathing in an enclosed space. Does inhaling oxygen of lower partial pressure affect the oxygen-carrying function of haemoglobin in vivo? This study uses non-invasive multiwavelength photoplethysmography to measure the effects that inhaling this type of oxygen can have on the plethysmography of the appendages of the body (fingertips). The results indicate that under low partial pressure of oxygen, be it the result of a gain in carbon dioxide concentration or altitude, the change in visible light absorption is the biggest for short wavelengths (approximately 620 or 640 nm) near deoxyhaemoglobin, which has higher absorption coefficient. Moreover, increasing carbon dioxide concentration from 5000 to 10,000 ppm doubly reduces the absorption rate of these short wavelengths.

Original languageEnglish
Pages (from-to)315-324
Number of pages10
JournalJournal of Medical Engineering and Technology
Issue number6
Publication statusPublished - 2016 Aug 17

All Science Journal Classification (ASJC) codes

  • Biomedical Engineering

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