Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2022
Extravascular leakage of induction doses of rocuronium: four cases in which both depth of neuromuscular block and plasma concentration of rocuronium were assessed.
The duration of action of extravasated rocuronium varies depending on the patient's comorbidities. In patients who receive high doses of non-depolarizing neuromuscular blocking agents subcutaneously, anesthesiologists should be aware of unexpected prolongation of the progress and recovery of neuromuscular block. In such cases, the depth and recovery of neuromuscular block should be objectively monitored to avoid residual neuromuscular block and recurarization.
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J Clin Monit Comput · Apr 2022
Multi-analyte calibration and verification of a multi-parameter laser-based pulse oximeter.
Almost since its introduction pulse oximetry was known to overestimate oxygen saturation in cases of carbon monoxide poisoning or elevated methemoglobin (metHb) levels. To eliminate this dangerous behavior some manufacturers have added additional LED emitters to try to increase the number of measured hemoglobin species and to improve measurement accuracy, but have not been very successful. We hypothesized that the use of narrow-band laser light sources would make accurate and precise measurement of the four primary species of hemoglobin possible, even in cases of elevated levels of carboxyhemoglobin (COHb). ⋯ This laser-based pulse oximeter measured all four species of hemoglobin accurately and precisely (ARMS ≤ 1.8%) for metHb levels in the clinically normal range. At elevated metHb levels the device continued to provide accurate and precise measurements of metHb and RHb (ARMS ≤ 1.7%). The use of monochromatic laser light sources can create a new generation of highly accurate, multi-parameter, pulse oximeters.
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The operation of the BIS monitor remains undescribed, despite 20 years of clinical use and 3000 academic articles. The core algorithmic software (the BIS Engine) can be retrieved from the motherboard of the A-2000 monitor in binary form through forensic disassembly using debugging interfaces left in place by the original designers, opening the possibility of executing the BIS algorithms on contemporary computers through emulation. Three steps were required for emulation. ⋯ Additive white noise in the EEG caused a progressive lifting and flattening of BIS values. Emulation replicates BIS Engine behavior, allowing calculation upon existing EEG datasets or signals from other, potentially remote or wireless, devices. Emulation provides advantages for elucidating the mathematical expression of the algorithms, which remain important as practical constraints on any hypothetical mechanism of action of anesthetics.
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J Clin Monit Comput · Apr 2022
Pupillary unrest, opioid intensity, and the impact of environmental stimulation on respiratory depression.
Opioid-induced respiratory depression (OIRD) confers significant morbidity, but its onset can be challenging to recognize. Pain or stimulation effects of conversation may mask or attenuate common clinical manifestations of OIRD. We asked whether pupillary unrest could provide an objective signal of opioid exposure, and whether this signal would be independent from the confounding influence of extrinsic stimulation. ⋯ PUAL is a consistent indicator of opioid effect, and distinguishes higher opioid concentrations independently of the stimulating effects of conversational interaction. Under equivalent opioid exposure, conversational interaction delayed the onset and minimized the severity of OIRD. Clinical trial registration: NCT04301895.
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Lactate levels are commonly used as an indirect measure to assess metabolic stress in clinical conditions like sepsis. Dynamic lactate measurements are recommended to assess and guide treatment in patients with shock and other critical care conditions. A minimally invasive, continuous lactate monitor has potential to improve clinical decisions and patient care. ⋯ The newly developed CLM has shown to be a promising tool to continuously measure lactate concentration in a minimally invasive fashion. Results indicate the CLM can provide needed trends in lactate over time. Such a device may be used in the future to improve treatment in clinical conditions such as sepsis.