Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients.

IntroductionRespiratory variation in arterial pulse pressure is a reliable predictor of fluid responsiveness in mechanically ventilated patients with circulatory failure. The main limitation of this method is that it requires an invasive arterial catheter. Both arterial and pulse oximetry plethysmographic waveforms depend on stroke volume. We conducted a prospective study to evaluate the relationship between respiratory variation in arterial pulse pressure and respiratory variation in pulse oximetry plethysmographic (POP) waveform amplitude.MethodThis prospective clinical investigation was conducted in 22 mechanically ventilated patients. Respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude were recorded simultaneously in a beat-to-beat evaluation, and were compared using a Spearman correlation test and a Bland-Altman analysis.ResultsThere was a strong correlation (r2 = 0.83; P < 0.001) and a good agreement (bias = 0.8 +/- 3.5%) between respiratory variation in arterial pulse pressure and respiratory variation in POP waveform amplitude. A respiratory variation in POP waveform amplitude value above 15% allowed discrimination between patients with respiratory variation in arterial pulse pressure above 13% and those with variation of 13% or less (positive predictive value 100%).ConclusionRespiratory variation in arterial pulse pressure above 13% can be accurately predicted by a respiratory variation in POP waveform amplitude above 15%. This index has potential applications in patients who are not instrumented with an intra-arterial catheter

Prediction of fluid responsiveness using respiratory variations in left ventricular stroke area by transoesophageal echocardiographic automated border detection in mechanically ventilated patients.

BackgroundLeft ventricular stroke area by transoesophageal echocardiographic automated border detection has been shown to be strongly correlated to left ventricular stroke volume. Respiratory variations in left ventricular stroke volume or its surrogates are good predictors of fluid responsiveness in mechanically ventilated patients. We hypothesised that respiratory variations in left ventricular stroke area (DeltaSA) can predict fluid responsiveness.MethodsEighteen mechanically ventilated patients undergoing coronary artery bypass grafting were studied immediately after induction of anaesthesia. Stroke area was measured on a beat-to-beat basis using transoesophageal echocardiographic automated border detection. Haemodynamic and echocardiographic data were measured at baseline and after volume expansion induced by a passive leg raising manoeuvre. Responders to passive leg raising manoeuvre were defined as patients presenting a more than 15% increase in cardiac output.ResultsCardiac output increased significantly in response to volume expansion induced by passive leg raising (from 2.16 +/- 0.79 litres per minute to 2.78 +/- 1.08 litres per minute; p < 0.01). DeltaSA decreased significantly in response to volume expansion (from 17% +/- 7% to 8% +/- 6%; p < 0.01). DeltaSA was higher in responders than in non-responders (20% +/- 5% versus 10% +/- 5%; p < 0.01). A cutoff DeltaSA value of 16% allowed fluid responsiveness prediction with a sensitivity of 92% and a specificity of 83%. DeltaSA at baseline was related to the percentage increase in cardiac output in response to volume expansion (r = 0.53, p < 0.01).ConclusionDeltaSA by transoesophageal echocardiographic automated border detection is sensitive to changes in preload, can predict fluid responsiveness, and can quantify the effects of volume expansion on cardiac output. It has potential clinical applications

Computing Semicommutation Closures: a Machine Learning Approach

Semicommutation relations are simple rewriting relation on finite words using rules of the form ab → ba. In this paper we present how to use Angluin style machine learning algorithms to compute the image of regular language by the transitive closure of a semicommutation relation

Thoroughly analyzing the use of ring oscillators for on-chip hardware trojan detection

International audienceWith the globalization of the IC design flow, structural integrity verification to detect parasitic electrical activities has emerged as an important research domain for testing the genuineness of an Integrated Circuit (IC). Sensors like Ring Oscil-lators (RO) have been proposed to precisely monitor the internal behaviour of the ICs. In this paper we propose an experimental analysis of the impact of parasitic electrical activities on the frequencies of ROs and on the internal supply voltages measured. Our observations lead us to identify the limits of the usability of ROs for practical and embedded detection of Hardware Trojans

Extraction of intrinsic structure for Hardware Trojan detection

Cryptology ePrint Archive: Report 2015/912In this paper we present a novel solution to address the problem of potential malicious circuitry on FPGA. This method is based on an a technique of structure extraction which consider the infection of an all lot. This structure is related to the design (place and route, power grid...) of the integrated circuits which composes the lot. In case of additional circuitry this design will be modify and the extracted structure will be affected. After developing the extraction techniques we present a method- ology to insert detection of hardware trojan and counterfeit in different IC manufacturing steps. At last an application example using 30 FPGA boards validate our extraction method. Finally, statistical tools are then applied on the experimental results to distinguish a genuine lot from an infected one and confirm the potential of detection the extracted structure

Electron deficient dicyanovinylene-ladder-type pentaphenylene derivative for n-type Organic Field Effect Transistors

International audienceA bridged pentaphenylene derivative functionalized with dicyanovinylene units LPP([double bond, length as m-dash]C(CN)2)2 has been designed, synthesized and characterized. The optical and electrochemical properties have been carefully studied through a combined experimental and theoretical approach and compared with those of two pentaphenylene derivatives bearing methylenes (LPP) or carbonyl (LPP([double bond, length as m-dash]O)2) on the bridgeheads. LPP([double bond, length as m-dash]C(CN)2)2 which possesses a very low LUMO level, ca. −4.02 eV, has been successfully used as an active layer in n-channel OFETs using the epoxy based photoresist SU-8 as a gate insulator. LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs show low voltage functioning (low gate-source and drain-source voltages), high ratio between the on and the off currents (2 × 105), interesting subthreshold swing (S = 1) and excellent stability under electrical stress and in a nitrogen atmosphere. More importantly, we have also shown that LPP([double bond, length as m-dash]C(CN)2)2 based n-channel OFETs present an excellent environmental stability. This work is to the best of our knowledge the first report on bridged pentaphenylene-based semiconductors in n-type OFETs and highlights the potential of such type of material to provide air stable OFETs

Fatigue cracks initiation in a low alloy steel: Impact of hydrogen on plasticity

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