Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 2017
Comparative StudyComparison of non-invasive peripheral venous saturations with venous blood co-oximetry.
The estimation of venous oxygen saturations using photoplethysmography (PPG) may be useful as a noninvasive continuous method of detecting changes in regional oxygen supply and demand (e.g. in the splanchnic circulation). The aim of this research was to compare PPG-derived peripheral venous oxygen saturations directly with venous saturation measured from co-oximetry blood samples, to assess the feasibility of non-invasive local venous oxygen saturation. This paper comprises two similar studies: one in healthy spontaneously-breathing volunteers and one in mechanically ventilated anaesthetised patients. ⋯ In the anaesthetised patients SxvO2 values were only 3.81% lower than SpO2 and tended to underestimate venous saturation (mean difference = -2.67 ± 5.89%) while correlating weakly with ScovO2 (r = 0.10). The results suggest that significant refinement of the technique is needed to sufficiently improve accuracy to produce clinically meaningful measurement of peripheral venous oxygen saturation. In anaesthetised patients the use of the technique may be severely limited by cutaneous arteriovenous shunting.
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J Clin Monit Comput · Dec 2017
Influence of continuously evolving transcatheter aortic valve implantation technology on cerebral oxygenation.
This study assessed the influence of the evolution in Transcatheter Aortic Valve Implantation technology on cerebral oxygenation. Cerebral oxygenation was measured continuously with Near-Infrared Spectroscopy and compared retrospectively between balloon-expandable, self-expandable and differential deployment valves which were implanted in 12 (34%), 17 (49%) and 6 patients (17%), respectively. Left and right SctO2 values were averaged at four time points and used for analysis (i.e. at baseline, balloon-aortic valvuloplasty, valve deployment, and at the end of the procedure). ⋯ Furthermore, both the incidence and duration below a cerebral oxygenation of 55% was significantly different between balloon and self-expandable valves (p = 0.038 and p = 0.018, respectively). This study demonstrated that Transcatheter Aortic Valve Implantation procedures are associated with significant cerebral desaturations, especially during balloon-aortic valvuloplasty and valve deployment. Moreover, our results showed that latest innovations in Transcatheter Aortic Valve Implantation technology beneficially influenced the adequacy of cerebral perfusion.
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J Clin Monit Comput · Dec 2017
Individualized assessment of post-arthroplasty recovery by actigraphy: a methodology study.
Previous studies using actigraphy to monitor recovery after total knee arthroplasty (TKA) have reported activity as maximum and average count/min, but not utilized the full potential of the data by stratifying activity into various intensities or analysed the individual development in activity over time. The aim of this study was to describe a novel methodology using actigraphy data to describe specific activity-intensities potentially affected by surgery and patients with poor rehabilitation trajectories. Actigraphy data from 10 patients scheduled for primary unilateral TKA were recorded preoperatively and for 3 weeks postoperatively. ⋯ The inter-individual variation increased with intensified activity. Identification of individual patients with positive, neutral or negative activity trajectories was possible. The methodology should be considered in future interventional studies to improve rehabilitation strategies.
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J Clin Monit Comput · Dec 2017
The influence of PEEP and positioning on central venous pressure and venous hepatic hemodynamics in patients undergoing liver resection.
In order to assess the occurrence of blood congestion in the liver during liver resection, we aimed to evaluate the influence of a positive-end-expiratory-pressure (PEEP) and positioning of patients on central venous pressure (CVP) and venous hepatic blood flow parameters. We further analyzed correlations between CVP and venous hepatic blood flow parameters. ⋯ Changes of central venous pressure due to changes of PEEP and positioning were not correlated with changes of venous hepatic blood flow parameters as measured after equilibration. Strategies aiming for low central venous pressure cannot be supported by these results. However, before ruling out low-CVP-strategies during liver resections these results should be confirmed by further studies.
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J Clin Monit Comput · Dec 2017
Phenylephrine increases near-infrared spectroscopy determined muscle oxygenation in men.
Phenylephrine increases mean arterial pressure (MAP) by enhanced total peripheral resistance (TPR) but near-infrared spectroscopy (NIRS) determined muscle oxygenation (SmO2) increases. We addressed that apparent paradox during supine rest and head-up tilt (HUT). Variables were determined ± phenylephrine in males during supine rest (n = 17) and 40° HUT (n = 7). ⋯ Brachial artery blood flow tended to decrease while SskinO2 together with StibialO2 decreased by 11% (P = 0.026) and 20% (P < 0.001), respectively. Conversely, phenylephrine increased SmO2 (9%) and restored the HUT elicited decrease in SmO2 (by 19%) along with SV (P = 0.02). Phenylephrine reduces skin and bone oxygenation and tends to reduce arm blood flow, suggesting that the increase in SmO2 reflects veno-constriction with consequent centralization of the blood volume.