Clinical investigation of plethysmographic variability index: A derivative index of pulse oximetry in anesthetized dogs

Plethysmographic Variability Index (PVI) is a derivative index of pulse oximetry that allows evaluating an individual\u27s intravascular volume status. Perfusion Index (PI) represents the strength of pulse signal at the anatomic site of measurement from which PVI is calculated using changes in PI over respiratory cycles. Plethysmographic Variability Index has been used to detect hypovolemia and predict fluid responsiveness in mechanically ventilated human patients however, fewer studies are available in spontaneously breathing patients. The use of PVI has not been explored extensively in dogs so far. The goals of this study were to establish a common range for PVI and assess relationship of the PVI, PI and various clinical variables in the anesthetized spontaneously breathing dogs. Values of PVI and PI derived from Masimo pulse oximetry were obtained at 5, 10, 15 and 20 minutes after anesthetic induction but before surgical stimulation together with cardiorespiratory variables that included heart rate, blood pressures (systolic, mean and diastolic blood pressures), respiratory rate and hemoglobin saturation of oxygen (SpO2) in 73 dogs with ASA 1-3 status admitted to the Purdue Teaching Hospital.^ Other clinical variables like body temperature, anesthetic protocol used, pre-induction packed cell volume (PCV) and total protein (TP) values, recumbency positions (sternal, lateral or dorsal recumbency) and rate of crystalloid fluids administration (5 vs 10 ml/kg/hr) were also obtained. Data were analysed using non-parametric Spearman\u27s rho coefficient and Kruskal Wallis one-way ANOVA by ranks to assess temporal relationship of PVI with all the clinical variables and with significant level set at P\u3c0.05. A common range of PVI was 5-43% with a median 18%. There was no significant correlation found between PVI and PI. Plethysmographic Variability Index positively correlated with the systolic blood pressure (rs=0.25; P\u3c0.001), mean blood pressure (rs=0.26; P\u3c0.001), diastolic blood pressure (rs=0.36; P\u3c0.001) and body temperature (rs=0.166; P=0.004). The other cardiorespiratory variables, recumbency positions, rate of crystalloid fluid administration, pre-operative PCV and TP values had no relationship with PVI. Premedication containing dexmedetomidine resulted in higher PVI (Kruskal-Wallis Test; P=0.001) and lower PI values (Kruskal-Wallis Test; P=0.004) and the opposite was true with protocols that contained acepromazine. It was concluded that while evaluating PVI for fluid response in the anesthetized dogs, various clinical factors should be taken into consideration

Self maps of homogeneous spaces

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Transient and asymptotic properties of robust adaptive controllers in the presence of non-coercive Lyapunov functions

— Adaptive control architectures often make use of Lyapunov functions to design adaptive laws. We are specifically interested in adaptive control methods, such as the well-known L1 adaptive architecture, which employ a parameter observer for this purpose. In such architectures, the observation error plays a critical role in determining analytical bounds on the tracking error as well as robustness. In this paper, we show how the non-existence of coercive Lyapunov operators can impact the analytical bounds, and with it the performance and the robustness of such adaptive systems

Static and dynamic calibrations of MSFC's plug-nozzle special test section /redesigned 1967/

Calibration of plug nozzle special test sectio

A Neighbor Coverage-Based Probabilistic Rebroadcast for Reducing Routing Overhead in Mobile Ad Hoc Networks Using Cluster Scheme

Due to high mobility of nodes in mobile ad hoc networks (MANETs), there exist frequent link breakages which lead to frequent path failures and route discoveries. The overhead of a route discovery cannot be neglected. In a route discovery, broadcasting is a fundamental and effective data dissemination mechanism, where a mobile node blindly rebroadcasts the first received route request packets unless it has a route to the destination, and thus it causes the broadcast storm problem. In this paper, we propose a neighbor coverage-based probabilistic rebroadcast protocol for reducing routing overhead in MANETs. In order to effectively exploit the neighbor coverage knowledge, we propose a novel rebroadcast delay to determine the rebroadcast order, and then we can obtain the more accurate additional coverage ratio by sensing neighbor coverage knowledge. We also define a connectivity factor to provide the node density adaptation. By combining the additional coverage ratio and connectivity factor, we set a reasonable rebroadcast probability. Our approach combines the advantages of the neighbor coverage knowledge and the probabilistic mechanism, which can significantly decrease the number of retransmissions so as to reduce the routing overhead, and can also improve the routing performance

Measuring the quantum statistics of an atom laser beam

We propose and analyse a scheme for measuring the quadrature statistics of an atom laser beam using extant optical homodyning and Raman atom laser techniques. Reversal of the normal Raman atom laser outcoupling scheme is used to map the quantum statistics of an incoupled beam to an optical probe beam. A multimode model of the spatial propagation dynamics shows that the Raman incoupler gives a clear signal of de Broglie wave quadrature squeezing for both pulsed and continuous inputs. Finally, we show that experimental realisations of the scheme may be tested with existing methods via measurements of Glauber's intensity correlation function.Comment: 4 pages, 3 figure

Increased serum levels of anti-filarial (IgA) antibodies in patients with tropical pulmonary eosinophilia

Tropical Pulmonary Eosinophilia (TPE) is diagnosed on the basis of high peripheral eosinophilia associated with clinical symptoms and signs. Elevated levels of total and antifilarial immunoglobulins is one of the characteristic features of TPE. Ten clinically diagnosed TPE patients and ten controls were compared for their anti-filarial and anti-ascaris antibody levels of classes IgG, IgM and IgA. While, IgG antibodies exhibited considerable cross reactivity between Ascaris and Filarial antigens, IgM antibodies showed nonspecific binding to filarial antigens. However, IgA antibodies were found to discriminate between TPE and control sera better than IgG and IgM antibodies