Anesthesia and analgesia
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Anesthesia and analgesia · May 2016
The Sounds of Desaturation: A Survey of Commercial Pulse Oximeter Sonifications.
The pulse oximeter has been a standard of care medical monitor for >25 years. Most manufacturers include a variable-pitch pulse tone in their pulse oximeters. Research has shown that the acoustic properties of variable-pitch tones are not standardized. In this study, we surveyed the properties of pulse tones from 21 pulse oximeters, consisting of 1 to 4 instruments of 11 different models and 8 brands. Our goals were to fully document the sounds over saturation values 0% to 100%, test whether tones become quieter at low saturation values, and create a public repository of pulse oximeter recordings for future use. ⋯ Current pulse oximeters use different techniques to address the competing goals of (1) using pitch steps that are large enough to be readily perceived, and (2) conveying saturation values from 0 to 100 within a limited range of sound frequencies. From a clinical perspective, 2 techniques for increasing perceivability (increasing the frequency range and using ratio step sizes) have no drawback, but 2 techniques (not changing pitch at every saturation change and using a lower saturation cutoff) do have potential clinical drawbacks. On the basis of our findings, we have made suggestions for clinicians and manufacturers.
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Anesthesia and analgesia · May 2016
The Effects of the Toll-Like Receptor 4 Antagonist, Ibudilast, on Sevoflurane's Minimum Alveolar Concentration and the Delayed Remifentanil-Induced Increase in the Minimum Alveolar Concentration in Rats.
Ultralow doses of naloxone, an opioid and toll-like receptor 4 antagonist, blocked remifentanil-induced hyperalgesia and the associated increase in the minimum alveolar concentration (MAC), but not tolerance. The aim was to determine the effects of the toll-like receptor 4 antagonist, ibudilast, on the MAC in the rat and how it might prevent the effects of remifentanil. ⋯ Ibudilast, besides reducing the MAC, prevented the delayed increase in baseline MAC produced by remifentanil but not the increase in MAC caused by tolerance to remifentanil.