Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2016
Observational StudyDiagnostic accuracy of stroke volume variation measured with uncalibrated arterial waveform analysis for the prediction of fluid responsiveness in patients with impaired left ventricular function: a prospective, observational study.
Uncalibrated arterial waveform analysis enables dynamic preload assessment in a minimally invasive fashion. Evidence about the validity of the technique in patients with impaired left ventricular function is scarce, while adequate cardiac preload assessment would be of great value in these patients. The aim of this study was to investigate the diagnostic accuracy of stroke volume variation (SVV) measured with the FloTrac/Vigileo™ system in patients with impaired left ventricular function. ⋯ Overall accuracy was 64 %, positive and negative predictive values were 69 and 56 % respectively. SVV values to obtain more than 90 % true positive and negative predictions were 16 and 6 % respectively. The ability of uncalibrated arterial waveform analysis SVV to predict fluid responsiveness in patients with impaired LVF was low.
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J Clin Monit Comput · Aug 2016
Observational StudyNear-infrared spectroscopy assessed cerebral oxygenation during open abdominal aortic aneurysm repair: relation to end-tidal CO2 tension.
During open abdominal aortic aneurism (AAA) repair cerebral blood flow is challenged. Clamping of the aorta may lead to unintended hyperventilation as metabolism is reduced by perfusion of a smaller part of the body and reperfusion of the aorta releases vasodilatory substances including CO2. We intend to adjust ventilation according end-tidal CO2 tension (EtCO2) and here evaluated to what extent that strategy maintains frontal lobe oxygenation (ScO2) as determined by near infrared spectroscopy. ⋯ Changes in ScO2 related to those in EtCO2 (r = 0.41; P = 0.0001) and cerebral deoxygenation (-15 %) was noted in three patients while cerebral hyperoxygenation (+15 %) manifests in one patient. Thus changes in ScO2 were kept within acceptable limits (±15 %) in 91 % of the patients. For the majority of the patients undergoing AAA repair ScO2 was kept within reasonable limits by reducing ventilation by approximately 1 l min(-1) upon clamping of the aorta and increasing ventilation by approximately 2 l min(-1) when the lower body is reperfused.
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J Clin Monit Comput · Aug 2016
Frequency domain analysis of cerebral near infrared spectroscopy signals during application of an impedance threshold device in spontaneously ventilating volunteers.
Currently available near infrared spectroscopy (NIRS) devices are unable to discriminate between arterial and venous blood, a potential source of artifact. The purpose of this study was to test the hypothesis that oscillations in NIR signals at the respiratory and cardiac frequency could be attributed to venous and arterial blood, respectively, and thereby isolated. After written informed consent was obtained, a two-wavelength NIRS device was placed over the left frontal cortex in 20 volunteers. ⋯ There were no other significant differences between pulsatile and non-pulsatile algorithms in the estimation of StO2. In 64 % of cases, both the low (ventilator) and high (cardiac) frequency estimates of StO2 were either both larger or both smaller than non-pulsatile StO2, suggesting that they were interrogating the same vascular bed. Frequency domain analysis cannot reliably separate NIRS waveforms into arterial and venous components.
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J Clin Monit Comput · Aug 2016
Comparative StudyContinuous noninvasive cardiac output determination using the CNAP system: evaluation of a cardiac output algorithm for the analysis of volume clamp method-derived pulse contour.
The CNAP system (CNSystems Medizintechnik AG, Graz, Austria) provides noninvasive continuous arterial pressure measurements by using the volume clamp method. Recently, an algorithm for the determination of cardiac output by pulse contour analysis of the arterial waveform recorded with the CNAP system became available. We evaluated the agreement of the continuous noninvasive cardiac output (CNCO) measurements by CNAP in comparison with cardiac output measurements invasively obtained using transpulmonary thermodilution (TDCO). ⋯ This pilot analysis shows that CNCO determination is feasible in critically ill patients. A percentage error of 25 % indicates acceptable agreement between CNCO-cal and TDCO. The mean difference, the standard deviation, and the percentage error between CNCO-auto and TDCO were higher than between CNCO-cal and TDCO. A hyperdynamic cardiocirculatory state in a substantial number of patients and the hemodynamic stability making trending analysis impossible are main limitations of our study.
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J Clin Monit Comput · Aug 2016
Randomized Controlled TrialThe effect of low-dose dexmedetomidine on hemodynamics and anesthetic requirement during bis-spectral index-guided total intravenous anesthesia.
The purpose of this study was to evaluate the effects of low-dose dexmedetomidine on hemodynamics and anesthetic requirements during propofol and remifentanil anesthesia for laparoscopic cholecystectomy. Thirty adult patients were randomly allocated to receive dexmedetomidine infusion of 0.3 μg/kg/h (dexmedetomidine group, n = 15) or comparable volumes of saline infusion (control group, n = 15). Target controlled infusion of propofol and remifentanil was used for anesthetic induction and maintenance, and adjusted in order to maintain a bispectral index of 40-55 and hemodynamic stability. ⋯ Significantly lower mean arterial pressure was observed in the dexmedetomidine group than in the control group at immediately and 5 min after pneumoperitoneum. The time to extubation after completion of drug administration did not differ between the groups (P = 0.25). This study demonstrated that a low-dose dexmedetomidine infusion of 0.3 μg/kg/h reduced propofol and remifentanil requirements as well as hemodynamic change by pneumoperitoneum without delayed recovery during propofol-remifentanil anesthesia for laparoscopic cholecystectomy.