A New Approach to High Reliability UHF Controllers

Many available UHF antenna positioners lack reliability for high-intensity commercial use. Similarly, many UHF antenna controllers lack appropriate interfaces for remote and automated control. We present a number of ways to simplify UHF ground station design and improve reliability. We also describe an improved antenna controller we have designed, with Ethernet connectivity, human- and machine-friendly interfaces, detailed metrics for fault diagnosis, and an improved control algorithm designed to minimise gearbox stresses and improve pointing accuracy

Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients

The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness

Model-Based Prediction of the Patient-Specific Response to Adrenaline

A model for the cardiovascular and circulatory systems has previously been validated in simulated cardiac and circulatory disease states. It has also been shown to accurately capture the main hemodynamic trends in porcine models of pulmonary embolism and PEEP (positive end-expiratory pressure) titrations at different volemic levels. In this research, the existing model and parameter identification process are used to study the effect of different adrenaline doses in healthy and critically ill patient populations, and to develop a means of predicting the hemodynamic response to adrenaline. The hemodynamic effects on arterial blood pressures and stroke volume (cardiac index) are simulated in the model and adrenaline-specific parameters are identified. The dose dependent changes in these parameters are then related to adrenaline dose using data from studies published in the literature. These relationships are then used to predict the future, patient-specific response to a change in dose or over time periods from 1-12 hours. The results are compared to data from 3 published adrenaline dosing studies comprising a total of 37 data sets. Absolute percentage errors for the identified model are within 10% when re-simulated and compared to clinical data for all cases. All identified parameter trends match clinically expected changes. Absolute percentage errors for the predicted hemodynamic responses (N=15) are also within 10% when re-simulated and compared to clinical data. Clinically accurate prediction of the effect of inotropic circulatory support drugs, such as adrenaline, offers significant potential for this type of model-based application. Overall, this work represents a further clinical, proof of concept, of the underlying fundamental mathematical model, methods and approach, as well as providing a template for using the model in clinical titration of adrenaline in a decision support role in critical care. They are thus a further justification in support of upcoming human clinical trials to validate this model

The Impact of Parameter Identification Methods on Drug Therapy Control in an Intensive Care Unit

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch Hospital Intensive Care Unit. The integral-based identification method has been previously clinically validated and extensively applied in a number of biomedical applications; and is a crucial element in the presented model-based therapeutics approach. Common non-linear regression and gradient descent approaches are too computationally intense and not suitable for the glucose control applications presented. The main focus in this paper is on better characterizing and understanding the importance of the integral in the formulation and the effect it has on model-based drug therapy control. As a comparison, a potentially more natural derivative formulation which has the same computation speed advantages is investigated, and is shown to go unstable with respect to modelling error which is always present clinically. The integral method remains robust

Improving hearing and vision in dementia : Protocol for a field trial of a new intervention

IntroductionQuality of life and other key outcomes may be improved by optimising hearing and vision function in people living with dementia. To date, there is limited research assessing the efficacy of interventions aimed at improving hearing and vision in people with dementia. Here, we outline a protocol to field test a newly developed home-based intervention, designed to optimise sensory functioning in people with dementia in three European sites. The results of this study will inform the design and conduct of a full-scale randomised controlled trial (RCT) in five European sites.Methods and analysisIn this multisite, single arm, open label, feasibility study, participants with dementia (n=24) will be assessed for hearing and vision impairments and be prescribed a hearing aid and/or glasses. Each participant will have a study partner (‘dyads’). A subset of dyads will receive ‘sensory support’ from a ‘sensory support therapist’, comprising home visits over 12 weeks. The therapist will offer the following intervention: adherence support for corrective devices; adaptations to the home environment to facilitate sensory function; communication training; and referral to community-based support services. The primary outcomes will be process measures assessing the feasibility, tolerability and acceptability of: (1) the intervention components; (2) the method of implementation of the intervention and (3) the study procedures, including outcome assessment measures. Quantitative data will be collected at baseline and follow-up. Qualitative data using semistructured interviews will be collected postintervention and weekly, using participant diaries. Finally, we will explore a model of cost-effectiveness to apply in the subsequent full-scale trial. This feasibility study is a necessary step in the development of a complex, individualised, psychosocial intervention. The data gathered will allow logistical and theoretical processes to be refined in preparation for a full-scale RCT.Ethics and disseminationEthical approval was obtained in all three participating countries. Results of the field trial will be submitted for publication in a peer-reviewed journal.</jats:sec

DISTq: An Iterative Analysis of Glucose Data for Low-Cost, Real-Time and Accurate Estimation of Insulin Sensitivity

Insulin sensitivity (SI) estimation has numerous uses in medical and clinical situations. However, highresolution tests that are useful for clinical diagnosis and monitoring are often too intensive, long and costly for regular use. Simpler tests that mitigate these issues are not accurate enough for many clinical diagnostic or monitoring scenarios. The gap between these tests presents an opportunity for new approaches

Mathematical model of the mitral valve and the cardiovascular system, application for studying, monitoring and in the diagnosis of valvular pathologies

peer reviewedA cardiovascular and circulatory system (CVS) model has been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiological accurate “open on pressure, close on flow” law. Thus, it does not consider the real time scale of the valve aperture dynamics and thus doesn’t fully capture valve dysfunction particularly where the dysfunction involves partial closure. This research describes a new closed-loop CVS model including a model describing the progressive aperture of the mitral valve and valid over the full cardiac cycle. This new model is solved for a healthy and diseased mitral valve

Implementation and evaluation of the SPRINT protocol for tight glycaemic control in critically ill patients: a clinical practice change

SPRINT was implemented as a clinical practice change in a general intensive care unit (ICU). The objective of this study was to measure the effect of the SPRINT protocol on glycaemic control and mortality compared to previous ICU control methods. Glycaemic control and mortality outcomes for 371 SPRINT patients with median acute physiology and chronic health evaluation (APACHE II) score 18 [IQR: 15-24] are compared to a 413 patient retrospective cohort with median APACHE II score of 18 [IQR: 15-23]