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Canadian Journal of Anesthesia

, Volume 53, Issue 1, pp 26–32 | Cite as

Audio spectrum and sound pressure levels vary between pulse oximeters

  • Deven Chandra
  • Michael J. Tessler
  • John Usher
General Anesthesia

Abstract

Purpose

The variable-pitch pulse oximeter is an important intraoperative patient monitor. Our ability to hear its auditory signal depends on its acoustical properties and our hearing. This study quantitatively describes the audio spectrum and sound pressure levels of the monitoring tones produced by five variable-pitch pulse oximeters.

Methods

We compared the Datex-Ohmeda Capnomac Ultima, Hewlett-Packard M1166A, Datex-Engstrom AS/3, Ohmeda Biox 3700, and Datex-Ohmeda 3800 oximeters. Three machines of each of the five models were assessed for sound pressure levels (using a precision sound level meter) and audio spectrum (using a hanning windowed fast Fourier transform of three beats at saturations of 99%, 90%, and 85%).

Results

The widest range of sound pressure levels was produced by the Hewlett-Packard M1166A (46.5 ± 1.74 dB to 76.9 ± 2.77 dB). The loudest model was the Datex-Engstrom AS/3 (89.2 ± 5.36 dB). Three oximeters, when set to the lower ranges of their volume settings, were indistinguishable from background operating room noise. Each model produced sounds with different audio spectra. Although each model produced a fundamental tone with multiple harmonic overtones, the number of harmonics varied with each model; from three harmonic tones on the Hewlett-Packard M1166A, to 12 on the Ohmeda Biox 3700. There were variations between models, and individual machines of the same model with respect to the fundamental tone associated with a given saturation.

Conclusion

There is considerable variance in the sound pressure and audio spectrum of commercially-available pulse oximeters. Further studies are warranted in order to establish standards.

Keywords

Operating Room Oxygen Saturation Sound Pressure Sound Pressure Level Pulse Oximeter 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Le spectre audible et les niveaux de pression sonore varient entre sphygmo-oxymètres

Résumé

Objectif

Le sphygmo-oxymètre à tonalité variable est un moniteur peropératoire important. Notre capacité à entendre son signal sonore dépend de ses propriétés acoustiques et de notre audition. Notre étude quantitative décrit le spectre audible et les niveaux de pression sonore des tonalités de monitorage produites par cinq sphygmo-oxymètres à tonalité variable.

Méthode

Nous avons comparé les oxymètres suivants: Datex-Ohmeda Capnomac Ultima, Hewlett-Packard M1166A, Datex-Engstrom AS/3, Ohmeda Biox 3700 et Datex-Ohmeda 3800. Trois appareils de chaque modèle ont été évalués pour les niveaux de pression sonore avec un sonomètre de précision, et pour le spectre audible en utilisant une transformée de Fourier à fenêtre Hanning de trois battements à des saturations de 99 %, 90 % et 85 %.

Résultats

La plus grande étendue de niveaux sonores a été produite par le Hewlett-Packard M1166A (46,5 ± 1,74 dB à 76,9 ± 2,77 dB). Le Datex-Engstrom AS/3 a produit la plus haute intensité sonore (89,2 ± 5,36 dB). Trois oxymètres, dont les paramètres de volume étaient fixés à de bas niveaux, ne pouvaient être entendus dans le bruit de la salle ďopération. Chaque modèle a produit des sons au spectre audible différent ayant un son fondamental et de multiples partiels harmoniques. Mais le nombre ďharmoniques variait selon le modèle, allant de trois pour le Hewlett-Packard M1166A à 12 pour le Ohmeda Biox 3700. Il y avait des variations entre les modèles et entre les appareils ďun même modèle quant au son fondamental associé à une saturation donnée.

Conclusion

Il y a une grande variation de pression sonore et de spectre audible pour les sphygmo-oxymètres offerts sur le marché. Il reste maintenant à fixer des normes.

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Copyright information

© Canadian Anesthesiologists 2006

Authors and Affiliations

  • Deven Chandra
    • 1
  • Michael J. Tessler
    • 2
  • John Usher
    • 3
  1. 1.Department of AnesthesiaMcGill UniversityMontréalCanada
  2. 2.Department of AnesthesiaSir Mortimer B. Davis-Jewish General Hospital, and McGill UniversityMontréalCanada
  3. 3.Multichannel Audio Research LaboratoryMcGill UniversityMontréalCanada

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