Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2017
Randomized Controlled TrialPerformance of a closed-loop feedback computer-controlled infusion system for maintaining blood pressure during spinal anaesthesia for caesarean section: a randomized controlled comparison of norepinephrine versus phenylephrine.
Closed-loop feedback computer-controlled vasopressor infusion has been previously described for maintaining blood pressure during spinal anaesthesia for caesarean section but there are limited data available comparing the relative performance of different vasopressors. The aim of this study was to compare the performance of norepinephrine versus phenylephrine in this system. Data from a randomized, two-arm parallel group, double-blinded controlled trial were reanalyzed. 104 patients scheduled for elective caesarean section under spinal anaesthesia were randomized to receive computer-controlled closed-loop infusion of either norepinephrine 5 µg ml-1 or phenylephrine 100 µg ml-1. ⋯ In addition, median performance error was smaller (0.75 [-1.56-2.52] %) versus 2.61 [0.83-4.57] %, P = 0.002) and wobble was smaller (2.85 [2.07-5.17] %) versus 3.39 [2.62-4.90] %, P = 0.028) in the norepinephrine group versus the phenylephrine group. Divergence was similar between groups. The precision of the control of blood pressure was greater with norepinephrine compared with phenylephrine at the drug concentrations used.
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J Clin Monit Comput · Jun 2017
ReviewUrine biochemistry assessment in critically ill patients: controversies and future perspectives.
In the past, urine biochemistry was a major tool in acute kidney injury (AKI) management. Classic papers published some decades ago established the values of the urine indices which were thought to distinguish "pre-renal" (functional) AKI attributed to low renal perfusion and "renal" (structural) AKI attributed to acute tubular necrosis (ATN). However, there were a lot of drawbacks and limitations in these studies and some recent articles have questioned the utility of measuring urine electrolytes especially because they do not seem to adequately inform about renal perfusion nor AKI duration (transient vs. persistent). ⋯ Some studies have suggested standardized changes in the urine electrolyte composition preceding increases in serum creatinine independently of AKI subsequent duration, which might actually be due to intra-renal microcirculatory changes and activation of sodium-retaining mechanisms even in the absence of impaired global renal blood flow. In the present review, the points of controversy regarding urine biochemistry assessment were evaluated as well as future perspectives for its role in AKI monitoring. An alternative approach for the interpretation of measured urine electrolytes is proposed which needs further larger studies to be validated and incorporated in daily ICU practice.
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J Clin Monit Comput · Jun 2017
Comparative Study Observational StudyEffect of patent ductus arteriosus and patent foramen ovale on left ventricular stroke volume measurement by electrical velocimetry in comparison to transthoracic echocardiography in neonates.
This prospective single-center observational study compared impedance cardiography [electrical velocimetry (EV)] with transthoracic echocardiography (TTE, based on trans-aortic flow) and analyzed the influence of physiological shunts, such as patent ductus arteriosus (PDA) or patent foramen ovale (PFO), on measurement accuracy. Two hundred and ninety-one triplicate simultaneous paired left ventricular stroke volume (LVSV) measurements by EV (LVSVEV) and TTE (LVSVTTE) in 99 spontaneously breathing neonates (mean weight 3270 g; range 1227-4600 g) were included. For the whole cohort, the mean absolute LVSVEVwas 5.5 mL, mean LVSVTTEwas 4.9 mL, resulting in an absolute Bland-Altman bias of -0.7 mL (limits of agreement LOA -3.0 to 1.7 mL), relative bias -12.8 %; mean percentage error MPE 44.9 %; true precision TPEV33.4 % (n = 99 aggregated data points). ⋯ In neonates with shunts (PDA and/or PFO; n = 67): mean LVSVEV5.8 mL, mean LVSVTTE5.0 mL, bias -0.8 mL (LOA -3.1 to 1.5 mL), relative bias -14.8 %, MPE 41.9 %, TPEV29.3 %. Accuracy was affected by PDA and/or PFO, with a significant increase in the relative difference in LVSVEVversus LVSVTTE: Subjects without shunts -2.9 % (n = 91), PFO alone -9.6 % (n = 125), PDA alone -14.0 % (n = 12), and PDA and PFO -18.5 % (n = 63). Physiological shunts (PDA and/or PFO) in neonates affect measurement accuracy and cause overestimation of LVSVEVcompared with LVSVTTE.
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J Clin Monit Comput · Jun 2017
Comparative StudyComparison of EtView™ tracheoscopic ventilation tube and video-assisted fiberoptic bronchoscopy during percutaneous dilatational tracheostomy.
Fiberoptic bronchoscopy (FOB) via endotracheal tube (ETT) is the most frequent utilized technique for monitoring of percutaneous dilatational tracheostomy (PDT) procedure while maintaining mechanical ventilation. Endoscopic guidance has increased the safety of this procedure; nevertheless, the use of a bronchoscope via ETT potentially may deteriorate ventilation and lead to hypercarbia and/or hypoxia. EtView tracheoscopic ventilation tube (EtView TVT) is a standard endotracheal tube with a camera and light source embedded at the tip. ⋯ The decrease in minute ventilation in Group FOB was higher when compared with Group EtView (51 ± 4 % vs. 12 ± 7.3 %, p < 0.05). The decrease in PaO2 from initial levels during (34 ± 21 % vs. 5 ± 7 % decrease) and after (26 ± 27 % vs. 2.8 ± 16 % decrease) the procedure was higher in Group FOB when compared with Group EtView (p < 0.05). Considering comparable features in monitorization and advantageous features over mechanical ventilation when compared with video bronchoscopy; EtView TVT would be a good alternative for airway monitorization during PDT especially for patients with poor pulmonary reserve.
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J Clin Monit Comput · Jun 2017
Analysis of central venous pressure (CVP) signals using mathematical methods.
Central venous pressure (CVP) is an important clinical parameter for physicians but only the absolute CVP value is typically monitored in the intensive care unit (ICU). In this study, we propose a novel mathematical method to present and analyze CVP signals. ⋯ The statistical features of time and frequency domain, wavelet, and empirical mode decomposition of these signals were extracted. We found no significant difference among the CVP signals regarding sex, smoking, coronary disease, and respiration mode of the samples.