Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2018
Changes in transcranial motor evoked potentials during hemorrhage are associated with increased serum propofol concentrations.
Transcranial motor evoked potentials (TcMEPs) monitor the integrity of the spinal cord during spine surgery. Propofol-based anesthesia is favored in order to enhance TcMEP quality. During intraoperative hemorrhage, TcMEP amplitudes may be reduced. ⋯ Multivariate analysis using hierarchical linear models indicated that the decline of TcMEP amplitude was primarily associated with rising propofol concentrations, but was also independently affected by reduced CO. We believe that the decrease in blood volume and CO during hemorrhage increased the serum concentration of propofol by reducing the volume of distribution and/or rate of hepatic metabolism of the drug. Despite wide acceptance of propofol as the preferred anesthetic when using TcMEPs, intravenous anesthetics are vulnerable to altered pharmacokinetics during conditions of hemorrhage and could contribute to false-positive TcMEP changes.
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J Clin Monit Comput · Jun 2018
Comparative StudyDiscrepancy between in vivo and in vitro comparisons of forced oscillation devices.
The forced oscillation technique (FOT) is an emerging clinical lung function test, with commercial devices becoming increasingly available. However comparability across existing devices has not been established. We evaluated in vivo and in vitro measurements made using three commercial devices against a custom-built device (WIMR): Resmon Pro Diary (Restech srl, Italy), tremoFlo C-100 (Thorasys Medical Systems, Canada), Jaeger Masterscope CT IOS (CareFusion, Hoechberg, Germany). ⋯ No differences were observed using test standards; deviation from theoretical value was <2% for resistance and <5% for reactance. The WIMR, tremoFlo and Resmon Pro but not IOS devices measure similar Rrs, whereas there was more disparity across devices in the estimation of Xrs parameters. The discrepancy between in vivo and in vitro measurements suggest that FOT validation procedures need to take into account the breathing pattern, either using biological controls or a breathing model.
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J Clin Monit Comput · Jun 2018
Comparative StudyComparing volume-clamp method and intra-arterial blood pressure measurements in patients with atrial fibrillation admitted to the intensive or medium care unit.
International guidelines highlight the importance of blood pressure (BP) in patients with atrial fibrillation (AF). However, BP measurement in AF is complicated by beat-to-beat fluctuation. Automated BP measurement devices are not validated for patients with AF and no consensus exists on how to measure BP in AF manually. ⋯ Accuracy of VCM in AF was similar to sinus rhythm. In conclusion, in patients with AF, accurate and precise measurement of non-invasive beat-to-beat BP measurement using the VCM is possible, the one exception being the precision of systolic BP. Beat-to-beat variability can be accurately reproduced.
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J Clin Monit Comput · Jun 2018
Meta AnalysisImpact of hemodynamic goal-directed resuscitation on mortality in adult critically ill patients: a systematic review and meta-analysis.
The effect of hemodynamic optimization in critically ill patients has been challenged in recent years. The aim of the meta-analysis was to evaluate if a protocolized intervention based on the result of hemodynamic monitoring reduces mortality in critically ill patients. We performed a systematic review and meta-analysis according to the Cochrane Handbook for Systematic Reviews of Interventions. ⋯ The mortality was 22.4% (374/1671 patients) in the intervention group and 22.9% (378/1652 patients) in the control group, OR 0.94 with a 95% CI of 0.73-1.22. We found no statistically significant reduction in mortality from hemodynamic optimization using hemodynamic monitoring in combination with a structured algorithm. The number of high quality trials evaluating the effect of protocolized hemodynamic management directed towards a meaningful treatment goal in critically ill patients in comparison to standard of care treatment is too low to prove or exclude a reduction in mortality.
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J Clin Monit Comput · Jun 2018
Randomized Controlled TrialThe effect of intravenous lidocaine infusion on bispectral index during major abdominal surgery.
Intraoperative lidocaine infusion has become widely accepted as an adjunct to general anesthesia where its use has been associated with opioid-sparing and enhanced recovery. The aims of this study were to determine whether or not intravenous (IV) lidocaine infusion (a) has an anesthetic sparing effect during major colorectal procedures and (b) if it also affects level of hypnosis as measured by bispectral index (BIS). Twenty-five patients undergoing laparotomy for resection of colorectal tumours were randomized to receive either IV lidocaine (1.5 mg kg-1 bolus then 1 mg kg-1 per hour) or an equivalent volume of normal saline commenced after intravenous induction of general anesthesia. ⋯ Higher BIS values in the lidocaine versus placebo group may indicate that levels of hypnosis were not equivalent. Alternatively, BIS may not be a sensitive indicator of synergistic interactions between local anesthetic and volatile agent. Our results advocate a cautious approach to titration of general anesthesia when combined with lidocaine infusion.