Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2007
Comparative StudyDark skin decreases the accuracy of pulse oximeters at low oxygen saturation: the effects of oximeter probe type and gender.
Pulse oximetry may overestimate arterial oxyhemoglobin saturation (Sao2) at low Sao2 levels in individuals with darkly pigmented skin, but other factors, such as gender and oximeter probe type, remain less studied. ⋯ Multivariate analysis indicated that Sao2 level, sensor type, skin color, and gender were predictive of errors in Spo2 estimates at low Sao2 levels. The data suggest that clinically important bias should be considered when monitoring patients with saturations below 80%, especially those with darkly pigmented skin; but further study is needed to confirm these observations in the relevant populations.
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Anesthesia and analgesia · Dec 2007
ReviewPhotoplethysmography: beyond the calculation of arterial oxygen saturation and heart rate.
In this article, I examine the source of the photoplethysmograph (PPG), as well as methods of investigation, with an emphasize on amplitude, rhythm, and pulse analysis. The PPG waveform was first described in the 1930s. Although considered an interesting ancillary monitor, the "pulse waveform" never underwent intensive investigation. ⋯ Future trends are being heavily influenced by modern digital signal processing, which is allowing a re-examination of this ubiquitous waveform. Key to unlocking the potential of this waveform is an unfettered access to the raw signal, combined with standardization of its presentation, and methods of analysis. In the long run, we need to learn how to consistently quantify the characteristics of the PPG in such a way as to allow the results from research efforts be translated into clinically useful devices.
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Anesthesia and analgesia · Dec 2007
Comparative Study Clinical TrialThe usefulness of an earphone-type infrared tympanic thermometer for intraoperative core temperature monitoring.
In this study we sought to determine the usefulness of a novel earphone-type infrared tympanic thermometer (IRT) for core temperature monitoring during surgery. ⋯ The earphone-type IRT might be used in a clinical setting for reliable and continuous core temperature monitoring during an operation.
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Anesthesia and analgesia · Dec 2007
Comparative StudyThe analgesic effects of opioids and immersive virtual reality distraction: evidence from subjective and functional brain imaging assessments.
Immersive virtual reality (VR) is a novel form of distraction analgesia, yet its effects on pain-related brain activity when used adjunctively with opioid analgesics are unknown. We used subjective pain ratings and functional magnetic resonance imaging to measure pain and pain-related brain activity in subjects receiving opioid and/or VR distraction. ⋯ These subjective pain reports and objective functional magnetic resonance imaging results demonstrate converging evidence for the analgesic efficacy of opioid administration alone and VR distraction alone. Furthermore, patterns of pain-related brain activity support the significant subjective analgesic effects of VR distraction when used as an adjunct to opioid analgesia. These results provide preliminary data to support the clinical use of multimodal (e.g., combined pharmacologic and nonpharmacologic) analgesic techniques.
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Anesthesia and analgesia · Dec 2007
Comparative StudyNew circulating-water devices warm more quickly than forced-air in volunteers.
Newer circulating-water systems supply more heat than forced-air, mainly because the heat capacity of water is much greater than for that of dry warm air and, in part, because they provide posterior as well as anterior heating. Several heating systems are available, but three major ones have yet to be compared directly. We therefore compared two circulating-water systems with a forced-air system during simulation of upper abdominal or chest surgery in volunteers. ⋯ The warming rate with the Kimberly Clark system was 25% faster than with the Allon system and twice as fast as with the Bair Hugger. Both circulating-water systems thus warmed hypothermic volunteers in significantly less time than the forced-air system.