Isolated forearm technique: a meta-analysis of connected consciousness during different general anaesthesia regimens

BACKGROUND: General anaesthesia should prevent patients from experiencing surgery, defined as connected consciousness. The isolated forearm technique (IFT) is the current gold standard for connected consciousness monitoring. We evaluated the efficacy of different anaesthesia regimens in preventing IFT responses. METHODS: We conducted a systematic review with meta-analysis of studies evaluating IFT in adults. Proportions of IFT-positive patients were compared for inhalational versus intravenous anaesthesia and anaesthesia brain monitor (ABM)-guided versus non-ABM-guided. RESULTS: Of 1131 patients in 22 studies, 393 (34.8%) had an IFT response during induction or maintenance. IFT-positive patients were less frequent during induction (19.7% [95% CI, 17.5-22.1]) than during maintenance (31.2% [95% CI, 27.8-34.8]). Proportions of IFT-positive patients during induction and maintenance were similar for inhalational (0.51 [95% CI, 0.38-0.65]) and intravenous (0.52 [95% CI, 0.26-0.77]) anaesthesia, but during maintenance were lower with inhalational (0.18 [95% CI, 0.08-0.38]) than with intravenous (0.48 [95% CI, 0.24-0.73]) anaesthesia. Proportions of IFT-positive patients during induction and maintenance were not significantly different for ABM-guided (0.64 [95% CI, 0.39-0.83]) and non-ABM-guided (0.48 [95% CI, 0.34-0.62]) anaesthesia but during maintenance were lower with non-ABM-guided (0.19 [95% CI, 0.09-0.37]) than with ABM-guided (0.57 [95% CI, 0.34-0.77]). Proportions of IFT-positive patients decreased significantly with increasing age and premedication use. Of the 34 anaesthesia regimens, 16 were inadequate. Studies had low methodological quality (only seven randomised controlled trials) and significant heterogeneity. CONCLUSIONS: Standard general anaesthesia regimens might not prevent connected consciousness. More accurate anaesthesia brain monitor methodology to reduce the likelihood of connected consciousness is desirable

Cantilever-based Resonant Microsensors with Integrated Temperature Modulation for Transient Chemical Analysis

This work introduces a resonant cantilever platform with integrated temperature modulation for real-time chemical sensing. Embedded heaters allow for rapid thermal cycling of individual sensors, thereby enabling real-time transient signal analysis without the need for a microfluidic setup to switch between analyte and reference gases. Compared to traditional mass-sensitive microsensors operating in steady state, the on-chip generation of signal transients provides additional information for analyte discrimination

Topologically non-trivial quantum layers

Given a complete non-compact surface embedded in R^3, we consider the Dirichlet Laplacian in a layer of constant width about the surface. Using an intrinsic approach to the layer geometry, we generalise the spectral results of an original paper by Duclos et al. to the situation when the surface does not possess poles. This enables us to consider topologically more complicated layers and state new spectral results. In particular, we are interested in layers built over surfaces with handles or several cylindrically symmetric ends. We also discuss more general regions obtained by compact deformations of certain layers.Comment: 15 pages, 6 figure

Cantilever-based Resonant Gas Sensors with Integrated Recesses for Localized Sensing Layer Deposition

This work presents mass-sensitive hammerhead resonators with integrated recesses as a gas-phase chemical microsensor platform. Recesses are etched into the head region of the resonator to locally deposit chemically sensitive polymers by ink-jet printing. This permits the sensing films to be confined to areas that (a) are most effective in detecting mass loading and (b) are not strained during the in-plane vibrations of the resonator. As a result of the second point, even 5-μm thick polymer coatings on resonators with a 9-12 μm silicon thickness barely affect the Q-factor in air. This translates into higher frequency stability and ultimately higher sensor resolution compared to uniformly coated devices

Raman spectroscopy, a non-destructive solution to the study of glass and its alteration

This paper presents the potential of Raman spectroscopy, a non-destructive technique which can be applied in-situ, for the analyses of glass and their alteration. Recent analytical developments are summarised for different glass composition and practical examples are given. The paper describes how to extract compositional information from the glass, first based on the spectra profile to distinguish rapidly alkali silicate from alkaline-earth alkali silicate and lead alkali silicate glass, then using the spectral decomposition and correlations to extract quantitative data. For alkali silicate glasses, that are most prone to alteration, the spectral characteristics are described to interpret the alteration process (selective leaching or dissolution of the glass) from the Raman spectra of the altered glass. These developments have greatly widened the potential of the technique and supplement well its ability to measure the thickness of the altered layer and identify the crystalline deposits

Modelling of precipitation during friction stir welding of an Al-Mg-Si alloy

In this study, microstructural evolution in AA 6082-T651 friction stir welds is simulated using a metallurgical model coupling a Monte Carlo random sampling technique and classical nucleation and growth theory. The calculated volume fraction and size distribution of precipitates are used to predict hardness. Some of the model parameters are calibrated from microstructure and hardness data available in the open literature. Temperature and hardness data in the region of the weld are obtained from FSW experiments. The temperature in the weld is predicted by finite element analysis, with a simplified thermo-mechanical approach, after calibration of heat transfer parameters in order to match the temperature measurements. The calculated thermal cycles are then applied to the metallurgical model. The subsequently predicted hardness profiles across the weld are then compared with experimental data

Missed Opportunities: Evolution of Patients Leaving without Being Seen or against Medical Advice during a Six-Year Period in a Swiss Tertiary Hospital Emergency Department.

Aim. The study aimed at describing the evolution over a 6-year period of patients leaving the emergency department (ED) before being seen ("left without being seen" or LWBS) or against medical advice ("left against medical advice" or LAMA) and at describing their characteristics. Methods. A retrospective database analysis of all adult patients who are admitted to the ED, between 2005 and 2010, and who left before being evaluated or against medical advice, in a tertiary university hospital. Results. During the study period, among the 307,716 patients who were registered in the ED, 1,157 LWBS (0.4%) and 1,853 LAMA (0.9%) patients were identified. These proportions remained stable over the period. The patients had an average age of 38.5 ± 15.9 years for LWBS and 41.9 ± 17.4 years for LAMA. The median time spent in the ED before leaving was 102.4 minutes for the LWBS patients and 226 minutes for LAMA patients. The most frequent reason for LAMA was related to the excessive length of stay. Conclusion. The rates of LWBS and LAMA patients were low and remained stable. The patients shared similar characteristics and reasons for leaving were largely related to the length of stay or waiting time

A predictive safety filter for learning-based racing control

The growing need for high-performance controllers in safety-critical applications like autonomous driving has been motivating the development of formal safety verification techniques. In this paper, we design and implement a predictive safety filter that is able to maintain vehicle safety with respect to track boundaries when paired alongside any potentially unsafe control signal, such as those found in learning-based methods. A model predictive control (MPC) framework is used to create a minimally invasive algorithm that certifies whether a desired control input is safe and can be applied to the vehicle, or that provides an alternate input to keep the vehicle in bounds. To this end, we provide a principled procedure to compute a safe and invariant set for nonlinear dynamic bicycle models using efficient convex approximation techniques. To fully support an aggressive racing performance without conservative safety interventions, the safe set is extended in real-time through predictive control backup trajectories. Applications for assisted manual driving and deep imitation learning on a miniature remote-controlled vehicle demonstrate the safety filter's ability to ensure vehicle safety during aggressive maneuvers

Five-year evolution of drug prescribing in a university adult intensive care unit

Introduction: Drug prescription is difficult in ICUs as prescribers are many, drugs expensive and decisions complex. In our ICU, specialist clinicians (SC) are entitled to prescribe a list of specific drugs, negotiated with intensive care physicians (ICP). The objective of this investigation was to assess the 5-year evolution of quantity and costs of drug prescription in our adult ICU and identify the relative costs generated by ICP or SC. Methods: Quantities and costs of drugs delivered on a quarterly basis to the adult ICU of our hospital between 2004 and 2008 were extracted from the pharmacy database by ATC code, an international five-level classification system. Within each ATC first level, drugs with either high level of consumption, high costs or large variations in quantities and costs were singled out and split by type of prescriber, ICP or SC. Cost figures used were drug purchase prices by the hospital pharmacy. Results: Over the 5-year period, both quantities and costs of drugs increased, following a nonsteady, nonparallel pattern. Four ATC codes accounted for 80% of both quantities and costs, with ATC code B (blood and haematopoietic organs) amounting to 63% in quantities and 41% in costs, followed by ATC code J (systemic anti-infective, 20% of the costs), ATC code N (nervous system, 11% of the costs) and ATC code C (cardiovascular system, 8% of the costs). Prescription by SC amounted to 1% in drug quantities, but 19% in drug costs. The rate of increase in quantities and costs was seven times larger for ICP than for SC (Figure 1 overleaf ). Some peak values in costs and quantities were related to a very limited number of patients. Conclusions: A 5-year increase in quantities and costs of drug prescription in an ICU is a matter of concern. Rather unexpectedly, total costs and cost increases were generated mainly by ICP. A careful follow-up is necessary to try influencing this evolution through an institutional policy co-opted by all professional categories involved in the process