New parameters of skin conductance compared with Bispectral Index monitoring to assess emergence from total intravenous anaesthesia

Background: Arousal after total i.v. anaesthesia (TIVA) has been reportedto be detectable by monitoring the number of fluctuations persecond (NFSC), a parameter of skin conductance (SC). However,compared with monitoring of the bispectral index (BIS^®),the predictive probability of NFSC was significantly lower.The aim of this study was to determine the value of the twonew, not yet published parameters of SC, area under the curve(AUC) methods A and B, for monitoring emergence from TIVA comparedwith monitoring of NFSC and BIS^®. Methods: Twenty-five patients undergoing surgery were investigated. NFSC,AUC A, AUC B, BIS^®, and haemodynamic parameters (mean arterialpressure and heart rate) were recorded simultaneously. The performanceof the monitoring devices in distinguishing between the clinicalstates ‘steady-state anaesthesia’, ‘firstclinical reaction’, and ‘extubation’ werecompared using the method of prediction probability (Pk) calculation. Results: BIS^® showed the best performance in distinguishing between‘steady-state anaesthesia’ vs ‘first reaction’(Pk BIS^® 0.95; NFSC 0.73; AUC A 0.54; AUC B 0.62) and ‘steady-stateanaesthesia’ vs ‘extubation’ (Pk BIS^®0.99; NFSC 0.73; AUC A 0.71; AUC B 0.67). However, the timefrom first BIS^®>60/SC>0 to a first clinical reactionwas significantly shorter for BIS^® (median BIS^® 180s; NFSC 780 s; AUC A 750 s; AUC B 690 s; P < 0.001). Conclusions: AUC A and AUC B did not improve accuracy of SC monitoring inpatients waking after TIVA.     

Multi-level approach to anaesthetic effects produced by sevoflurane or propofol in humans: 1. BIS and blink reflex

Background: The relative roles of forebrain and brainstem in producing adequateanaesthesia are unclear. Methods: We simultaneously analysed the effects of sevoflurane (GroupS; n = 18) or propofol (Group P; n = 29) on the bispectral index(BIS) and the first component of the blink reflex (R1). Thedose of anaesthetic agent was increased until loss of blinkreflex. After discontinuation and reappearance of blink reflexactivity, the amount was increased again. The area under curveR1 (area-R1) of the electromyogram of the orbicularis oculimuscle after electrical stimulation of the supraorbital nervewas measured. Using a sigmoid E_max model and a first-order rateconstant k_e0, we characterized the dose–response relationshipsfor BIS and area-R1. Results: Concentration-dependent depression of BIS and area-R1 was adequatelymodelled. The concentration that causes an effect midway betweenminimum and maximum (EC₅₀) for area-R1 was smaller than EC₅₀for BIS in both groups [0.34 (0.19) vs 1.29 (0.19) vol% and1.78 (0.65) vs 2.69 (0.67) µg ml^–1; mean (SD)].At doses of sevoflurane and propofol with equivalent depressionof BIS, sevoflurane depressed area-R1 more than propofol. Thek_e0 for area-R1 was about half that for BIS in both groups:0.24 (0.19–0.29) vs 0.48 (0.38–0.60) min^–1for Group S; 0.28 (0.23–0.34) vs 0.46 (0.40–0.54)min^–1 for Group P, geometric mean (95% CI). Conclusions: The blink reflex (brainstem function) is more sensitive to sevofluraneor propofol than BIS (forebrain function). Sevoflurane suppressesthe blink reflex more than propofol. Different k_e0s for blinkreflex vs BIS indicate different effect sites.     

A hierarchical approach to optimized control of water distribution systems: Part I decomposition

Consideration is given to the problem of evaluating optimized control schedules for common types of water distribution systems. For these systems the major operating costs are associated with electricity charges for pumped source supplies. This paper provides a rigorous formulation for system operations. Proposals are then made for hierarchical decomposition into these levels: an upper level for dynamic optimization of reservoir storage, an intermediate level for static optimization of source extraction and a tower level for static optimization of individual sources.     

Multi-level approach to anaesthetic effects produced by sevoflurane or propofol in humans: 2. BIS and tetanic stimulus-induced withdrawal reflex

Background: General anaesthesia could be assessed at two sites: corticalstructures and the spinal cord. However, the practicalitiesof measurement at these two sites differ substantially. Methods: We simultaneously analysed effects of sevoflurane (Group S;n = 16) or propofol (Group P; n = 17) on bispectral index (BIS)and the tetanic stimulus-induced withdrawal reflex (TIWR). TIWRwas quantified by the area under the curve of the electromyogramof the biceps femoris muscle after electrical stimulation ofthe sural nerve. After loss of consciousness, TIWR was evokedonce per minute. The anaesthetic was increased until TIWR disappeared.After discontinuation of the anaesthetic and reappearance ofTIWR, the amount of anaesthetic was increased again. Using asigmoid E_max model and a first-order rate constant k_e0, we characterizedthe dose–response relationships for BIS and TIWR. Results: Concentration-dependent depression of TIWR was reasonably wellmodelled for sevoflurane, but poorly for propofol. TIWR wascompletely suppressed by sevoflurane, but not propofol. Sevofluranereduced TIWR to 5 mV ms (very weak movement) at 1.68 vol% end-expiredconcentration [ minimum alveolar concentration (MAC value)].The k_e0s for TIWR were smaller than those for BIS: 0.25 (0.16–0.39)vs 0.41 (0.33–0.51) min^–1 for Group S; 0.25 (0.22–0.30)vs 0.34 (0.29–0.40) min^–1 for Group P [geometricmean (95% CI)]. Conclusions: High concentrations of sevoflurane depress TIWR more than propofol.With propofol, we frequently observed a paradoxical behaviourof muscles of the lower leg. TIWR lags behind BIS, indicatingdifferent effect sites for two intended anaesthetic effects:unresponsiveness to noxious stimulation and unconsciousness.     

Stochastic model predictive control approaches applied to drinking water networks

Control of drinking water networks is an arduous task, given their size and the presence of uncertainty in water demand. It is necessary to impose different constraints for ensuring a reliable water supply in the most economic and safe ways. To cope with uncertainty in system disturbances due to the stochastic water demand/consumption and optimize operational costs, this paper proposes three stochastic model predictive control (MPC) approaches, namely, chance‐constrained MPC, tree‐based MPC, and multiple‐scenario MPC. A comparative assessment of these approaches is performed when they are applied to real case studies, specifically, a sector and an aggregate version of the Barcelona drinking water network in Spain. Copyright © 2016 John Wiley & Sons, Ltd.     

A unified approach to reduced-order modelling and control of large-scale systems with multiple decision makers

This paper presents a unified approach to reduced-order modelling and control of large-scale systems with multiple decision makers. The ‘core’ of a large game problem is identified through the information structure and the class of structure preserving strategies. The induced decomposition results in a low-order game problem and two decentralized optimal control problems. An example of a two-area power system demonstrates the computational attractiveness of the proposed design methodology.     

Significance of Screening Tests and the Incidence of New Delhi Metallo-beta-lactamase-Producing Gram-negative Bacilli in the Surgery and Transplantation Wards of a Warsaw Medical Center During the Period From April 2014 to May 2017

Background

The first New Delhi metallo-beta-lactamase (NDM)-producing bacteria were isolated in 2008 in the world, and in 2011 in Poland. Due to the high clonal diversity (17 types) of their blaNDM gene, encoded on (Tn125-like) mobile genetic elements, these strains usually exhibit resistance to nearly all available antibiotics, which is particularly dangerous for organ transplant recipients.