19 research outputs found
Comment on "Secure direct communication with a quantum one-time pad"
In the paper [Phys. Rev. A \textbf{69}, 052319 (2004)], a quantum direct
communication protocol is proposed which is claimed to be unconditionally
secure even for the case of a noisy channel. We show that this is not the case
by giving an undetectable attack scheme
Pragmatic approach to nutrition in the ICU: Expert opinion regarding which calorie protein target
BACKGROUND & AIMS:Since the publications of the ESPEN guidelines on enteral and parenteral nutrition in ICU, numerous studies have added information to assist the nutritional management of critically ill patients regarding the recognition of the right population to feed, the energy-protein targeting, the route and the timing to start.
METHODS: We reviewed and discussed the literature related to nutrition in the ICU from 2006 until October 2013.
RESULTS: To identify safe, minimal and maximal amounts for the different nutrients and at the different stages of the acute illness is necessary. These amounts might be specific for different phases in the time course of the patient's illness. The best approach is to target the energy goal defined by indirect calorimetry. High protein intake (1.5 g/kg/d) is recommended during the early phase of the ICU stay, regardless of the simultaneous calorie intake. This recommendation can reduce catabolism. Later on, high protein intake remains recommended, likely combined with a sufficient amount of energy to avoid proteolysis.
CONCLUSIONS: Pragmatic recommendations are proposed to practically optimize nutritional therapy based on recent publications. However, on some issues, there is insufficient evidence to make expert recommendations
Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration
<p>Abstract</p> <p>Background</p> <p>Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (CO<sub>PAC</sub>) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (CO<sub>AP</sub>) device (FloTracâą, Vigileoâą; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU) using CO<sub>PAC </sub>as the method of reference.</p> <p>Methods</p> <p>We studied 20 critically ill patients, aged 16 to 74 years (mean, 55.5 ± 18.8 years), who required both arterial and pulmonary artery pressure monitoring. CO<sub>PAC </sub>measurements were performed at least every 4 hours and calculated as the average of 3 measurements, while CO<sub>AP </sub>values were taken immediately at the end of bolus determinations. Accuracy of measurements was assessed by calculating the bias and limits of agreement using the method described by Bland and Altman.</p> <p>Results</p> <p>A total of 164 coupled measurements were obtained. Absolute values of CO<sub>PAC </sub>ranged from 2.80 to 10.80 l/min (mean 5.93 ± 1.55 l/min). The bias and limits of agreement between CO<sub>PAC </sub>and CO<sub>AP </sub>for unequal numbers of replicates was 0.02 ± 2.92 l/min. The percentage error between CO<sub>PAC </sub>and CO<sub>AP </sub>was 49.3%. The bias between percentage changes in CO<sub>PAC </sub>(ÎCO<sub>PAC</sub>) and percentage changes in CO<sub>AP </sub>(ÎCO<sub>AP</sub>) for consecutive measurements was -0.70% ± 32.28%. CO<sub>PAC </sub>and CO<sub>AP </sub>showed a Pearson correlation coefficient of 0.58 (<it>p </it>< 0.01), while the correlation coefficient between ÎCO<sub>PAC </sub>and ÎCO<sub>AP </sub>was 0.46 (<it>p </it>< 0.01).</p> <p>Conclusion</p> <p>Although the CO<sub>AP </sub>algorithm shows a minimal bias with CO<sub>PAC </sub>over a wide range of values in an inhomogeneous group of critically ill patients, the scattering of the data remains relative wide. Therefore, the used algorithm (V 1.03) failed to demonstrate an acceptable accuracy in comparison to the clinical standard of cardiac output determination.</p
Reliability of Continuous Pulse Contour Cardiac Output Measurement during Hemodynamic Instability
Objective Arterial pulse contour analysis is gaining widespread acceptance as a monitor of continuous cardiac output (CO). While this type of CO measurement is thought to provide acceptable continuous measurements, only a few studies have tested its accuracy and repeatability under unstable hemodynamic conditions. We compared continuous CO measurement using the pulse contour method (PCCO) before and after calibration with intermittent transpulmonary thermodilution cardiac output (TpCO). Method We compared the two methods of CO measurements in 15 Landrace pigs weighing 20â25 kg in an experimental model of sepsis. Nine pigs were given an infusion of E. coli lipopolysacchride (LPS), and six pigs acted as controls. PCCO values before and after calibration (PCCO1 and PCCO2 respectively) were registered, and their errors relative to TpCO measurements were compared. Results The mean coefficient of variation for repeated PCCO measurements was 6.85% for the control group, and 13.99% for the endotoxin group. The range of TpCO was 1.01â3.15 L/min. In the control group the bias ±2SD was 0.11 ± 0.53 L/min (TpCO vs PCCO1) and â0.02 ± 0.38 L/min (TpCO vs PCCO2). In the endotoxin group, the agreement was poor between TpCO and PCCO1, 0.08 ± 1.02 L/min. This improved after calibration (TpCO vs PCCO2) to 0.01 ± 0.31 L/min. Conclusions In hemodynamically stable pigs, both pre- and post-calibration PCCO measurements agreed well with the intermittent transpulmonary thermodilution technique. However, during hemodynamic instability, and pre-calibration PCCO values had wide limits of agreement compared with TpCO. This was reflected by larger coefficients of variation for PCCO in hemodynamic instability. The error of PCCO measurement improved markedly after calibration, with bias and limits of agreement within clinically acceptable limits