Objective: Intradialytic haemodynamic instability is a significant clinical problem, leading to end-organ ischaemia and contributing to morbidity and mortality in haemodialysis patients. Non-invasive ...continuous blood pressure monitoring is not currently part of routine practice but may aid detection and prevention of significant falls in blood pressure during dialysis. Brachial blood pressure is currently recorded intermittently during haemodialysis via a sphygmomanometer. Current methods of continuous non-invasive blood pressure monitoring tend to restrict movement, can be sensitive to external disturbances and patient movement, and can be uncomfortable for the wearer. Additionally, poor patient blood circulation can lead to unreliable measurements. In this feasibility study we performed an initial validation of a novel method and associated technology to continuously estimate blood pressure using pressure sensors in the extra-corporeal dialysis circuit, which does not require any direct contact with the person receiving dialysis treatment. Method: The paper describes the development of the measurement system and subsequent in vivo patient feasibility study with concurrent measurement validation by Finapres Nova physiological measurement device. Real-time physiological data is collected over the entire period of (typically 4-hour) dialysis treatment. Results: We identify a quasi-linear mathematical function to describe the relationship between arterial line pressure and brachial artery BP, which is confirmed in a patient study. The results from this observational study suggest that it is feasible to derive a continuous measurement of brachial pressure from continuous measurements of arterial and venous line pressures via an empirically based and updated mathematical model. Conclusion: The methodology presented requires no interfacing to proprietary dialysis machine systems, no sensors to be attached to the patient directly, and is robust to patient movement during treatment and also to the effects of the cyclical pressure waveforms induced by the hemodialysis peristaltic blood pump. This represents a key enabling factor to the development of a practical continuous blood pressure monitoring device for dialysis patients.
Non-invasive continuous blood pressure monitoring is not yet part of routine practice in renal dialysis units but could be a valuable tool in the detection and prevention of significant variations in ...patient blood pressure during treatment. Feasibility studies have delivered an initial validation of a method which utilises pressure sensors in the extra-corporeal dialysis circuit, without any direct contact with the person receiving treatment. Our main objective is to further develop this novel methodology from its current early development status to a continuous-time brachial artery pressure estimator.
During an in vivo patient feasibility study with concurrent measurement validation by Finapres Nova experimental physiological measurement device, real-time continuous dialysis line pressures, and intermittent occluding arm cuff pressure data were collected over the entire period of (typically 4-hour) dialysis treatments. There was found to be an underlying quasi-linear relationship between arterial line and brachial pressure measurements which supported the development of a mathematical function to describe the relationship between arterial dialysis line pressure and brachial artery BP. However, unmodelled non-linearities, dynamics and time-varying parameters present challenges to the development of an accurate BP estimation system. In this paper, we start to address the problem of physiological parameter time variance by novel application of an iterative learning run-to-run modelling methodology originally developed for process control engineering applications to a parameterised BP model.
The iterative run-to-run learning methodology was applied to the real-time data measured during an observational study in 9 patients, supporting subsequent development of an adaptive real-time BP estimator. Tracking of patient BP is analysed for all the subjects in our patient study, supported only by intermittent updates from BP cuff measurements.
The methodology and associated technology is shown to be capable of tracking patient BP non-invasively via arterial line pressure measurement during complete 4-hour treatment sessions. A robust and tractable method is demonstrated, and future refinements to the approach are defined.
•Non-invasive continuous blood pressure monitoring is not yet part of routine practice in renal dialysis units.•Feasibility studies have delivered an initial validation of a method utilizing sensors in the dialysis circuit.•Main objective is to further develop this method to a continuous-time brachial artery pressure estimator.•There was found to be a quasi-linear relationship between arterial line and brachial pressure measurements.•In this paper, we start to address physiological parameter time variance.•We use a novel application of an iterative learning run-to-run modelling methodology in an adaotive model.•The methodology was applied to the real-time data measured during an observational study.•Tracking of patient BP is analysed for all the subjects, supported by updates from BP cuff measurements.•The methodology and associated technology is shown to be capable of tracking BP non-invasively via arterial line measurement.
Trojans, phishing, rootkits and worms all have one thing in common: they are instruments of cybercrime. These and other forms of malware form the sharp end of a complex network of criminal activity ...designed to exploit computer users, and according to Mel Morris, CEO of Prevx, the cybersecurity community could be doing better at catching these malware attacks.
In this article, Morris explores the cybercrime landscape, and finds out what we could be doing more effectively.
For three decades, information security has struggled to contain the evolution of malicious software. Viruses, worms, spyware, rootkits, Trojans and phishing have all enjoyed their reign of terror. The spyware years (2000–2003) showed how the security industry was caught off-guard when most of the major security vendors took an agonising two to three years to respond to a new category of threat that affected hundreds of millions of users. Had it not been for the start-up vendors such as Lavasoft, Webroot, Safer Networking and Giant, who quickly plugged a hole for an estimated 250 million PC users, order may never have been restored. It was a close-run thing. Had organised crime spotted and leveraged the opportunity afforded by sluggish vendors, then the effects would have been catastrophic. Fortunately, spyware at this time was more about exploitation of internet advertising than bank accounts or industrial espionage.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
10.
Option Appraisal in the NHS (Part 2) Woodward, David; Morris, Mel; Jones, Chris
Financial management (London, England),
02/1991, Letnik:
69, Številka:
2
Journal Article
In 1984, the Mansfield and Ashfield Appeal Committee, a UK charitable trust, was formed to obtain, by various charitable means, public subscription to a level of L500,000 in order to procure a ...computer-aided tomography (CAT) scanner for use at the Kings Mill Hospital (Nottinghamshire). The committee decided to adopt a multidisciplinary project team approach to procure the scanner, using terotechnological principles associated with the specification, design, and installation stages of asset management. A project team, formed under the leadership of the chairman of the appeal committee, decided to use life cycle costing techniques to carry out the option appraisal. This would ensure compliance with Capricode's requirement of best value for the money and the NEDC specification that option appraisal should occur prior to capital investment decisions. The use of these techniques enabled the lifetime financial consequences of asset ownership to be assessed against a variety of assumptions.
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