Can people hear the pitch change on a variable-pitch pulse oximeter?

G. Todd Schulte, Frank E Block

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


The introduction of the variable-pitch feature on pulse oximeters in 1983 by the Nellcor Corporation (Hayward, CA) allowed users to rapidly detect changes in oxygen saturation by listening for changes in the pitch of the tones emitted by the pulse oximeter. A few individuals have reported that they have been unable to detect a change in pitch when oxygen saturation changes. To these individuals, the variable-pitch feature of these pulse oximeters has not been beneficial. Using the pitches from one manufacturer of oximeters, we created a computer program to simulate the pitches that accompanied various oxygen saturations. The pitches were recorded onto a tape player and played for 75 volunteer subjects unfamiliar with the pitches of a variable-pitch pulse oximeter. Of our sample, 67% were able to detect a single change in pitch corresponding to a 1% fall in oxygen saturation, and 11% of the population could not detect a change in pitch until there was a change in pitch with every beat. We suggested four alternative designs that may prove beneficial to this group of individuals.

Original languageEnglish (US)
Pages (from-to)198-200
Number of pages3
JournalJournal of Clinical Monitoring
Issue number3
StatePublished - Jul 1 1992
Externally publishedYes


  • Equipment: pulse oximeters
  • Hearing
  • Measurement techniques: pulse oximetry

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine


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