Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2015
Comparative StudyNoninvasive assessment of peripheral microcirculation by near-infrared spectroscopy: a comparative study in healthy smoking and nonsmoking volunteers.
Smokers are exposed to early endothelial dysfunction. This microcirculatory damage can be demonstrated by near-infrared spectroscopy (NIRS). The aim of this study was to compare microvascular reactivity by NIRS during a dynamic vascular occlusion test in healthy smokers and nonsmokers volunteers. ⋯ It was the same for the rate of resaturation [smokers 30.4%·min(-1) (range 14.2-51.6) and nonsmokers 30.5%·min(-1) (range 18.6-44.5); p = 0.82]. NIRS study of microvascular reactivity during a dynamic vascular occlusion test did not reveal any difference between smokers and nonsmokers. Therefore, NIRS could not be sensitive enough to highlight endothelial dysfunction in healthy subjects exposed to tobacco smoke.
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J Clin Monit Comput · Oct 2015
Comparative StudyEvaluation of filtering methods for acquiring radial intra-artery blood pressure waveforms.
The methods for evaluating noninvasive blood pressure (NIBP) monitors using an intra-arterial reference are detailed in the ANSI/AAMI/ISO 81060-2:2009 standard. In a recent study, GE Healthcare obtained invasive radial arterial blood pressure waveforms. The work presented here describes the development of filtering strategies for obtaining high fidelity intra-arterial pressure waveforms for NIBP accuracy testing using the 81060-2 standard. ⋯ Clinicians need to understand that resonance artifacts potentially exist in intra-arterial waveforms and that the adjustments of monitoring systems may not be adequate. Optimal filters for obtaining intra-arterial waveforms should take into account the damping factor and natural frequency of the measuring system. In research and device evaluation studies it is necessary that optimal filtering be done to minimize the effects of under-damping.
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J Clin Monit Comput · Oct 2015
Reliability of the volatile agent consumption display in the Draeger Primus™ anesthesia machine.
Knowledge of the consumed amount of volatile anesthetic (VA) expressed in liquid agent is necessary to enable agent sparing dosing measures and for billing purposes. The widespread Draeger Primus™ anesthesia machine displays in its logbook the amount of consumed VA at the end of each anesthesia, but the reliability of this parameter is yet unknown. The objective was to evaluate the precision and reliability of the inbuilt VA consumption display in Draeger Primus™ anesthesia machines as compared with the gold standard of weighing the vaporizer before and after anesthesia. ⋯ The displayed desflurane consumption underestimated the measured values by -3.5 ± 6.3 ml (6.2%). Nine from 10 sevoflurane pairs of values and all desflurane pairs of values were within ±1.96 SD. The displayed VA consumption calculations for sevoflurane and desflurane in the Draeger Primus™ are sufficiently reliable to estimate the pharmacoeconomic impact of VA delivery during inhalational anesthesia.
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J Clin Monit Comput · Oct 2015
Utility of near infrared light to determine tissue oxygenation during hepato-biliary surgery.
Near-infrared spectrophotometry assesses cerebral oxygen saturation (ScO2) based on the absorption spectra of oxygenated and deoxygenated hemoglobin, and the translucency of biological tissue, in the near-infrared band. There is increasing evidence that optimising cerebral oxygenation, guided by ScO2, is associated with improved outcomes in a variety of high risk surgical settings. However, in patients with liver disease, bilirubin can potentially render cerebral oximetry inaccurate. ⋯ However, those patients with low ScO2 (≤51%) maintained a similar trend in cerebral oximetry values both at induction and intraoperatively to those with a normal ScO2. We conclude that the pattern of cerebral oximetry is similar in patients undergoing major pancreatic surgery regardless of their underlying liver dysfunction. Therefore, cerebral oximetry may have a role in monitoring neurological function in this high risk group of patients.