Abstract
An anesthesiologist must remain vigilant of the patient’s clinical status, incorporating many independent physiological measurements. Oxygen saturation and heart rate are represented by continuous audible tones generated by the pulse oximeter, a mandated monitoring device. Other important clinical parameters—notably blood pressure—lack any audible representation beyond arbitrarily-configured threshold alarms. Attempts to introduce further continuous audible tones have apparently foundered; the complexity and interaction of these tones have exceeded the ability of clinicians to interpret them. Instead, we manipulate the tonal and rhythmic structure of the accepted pulse oximeter tone pattern melodically. Three melodic algorithms were developed to apply tonal and rhythmic variations to the continuous pulse oximeter tone, dependent on the systolic blood pressure. The algorithms distort the original audible pattern minimally, to facilitate comprehension of both the underlying pattern and the applied variations. A panel of anesthesia practitioners (attending anesthesiologists, residents and nurse anesthetists) assessed these algorithms in characterizing perturbations in cardiopulmonary status. Twelve scenarios, incorporating combinations of oxygen desaturation, bradycardia, tachycardia, hypotension and hypertension, were tested. A rhythmic variation in which additional auditory information was conveyed only at halftime intervals, with every other “beat” of the pulse oximeter, was strongly favored. The respondents also strongly favored the use of musical chords over single tones. Given three algorithms of tones embedded in the pulse oximeter signal, anesthesiologists preferred a melodic tone to signal a significant change in blood pressure.
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This work was supported by intradepartmental funds only. No external financial support was obtained.
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The authors declare that they have no conflict of interest.
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The authors declare that the experiments comply with the current laws of the United States of America, the country in which they were performed.
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The “supplementary material” refers to the software that we wrote that generates the auditory alarms described in the text, as shown in Fig. 2 and as cited in the references. The software may be obtained from this address: http://www.mit.edu/~cwc/PulseOx.exe.
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Chima, R.S., Ortega, R. & Connor, C.W. Melodic algorithms for pulse oximetry to allow audible discrimination of abnormal systolic blood pressures. J Clin Monit Comput 28, 597–603 (2014). https://doi.org/10.1007/s10877-014-9558-6
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DOI: https://doi.org/10.1007/s10877-014-9558-6