Browsing by Author "Boonzaier, David"

Now showing 1 - 7 of 7
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    Assessment of catheter-manometer systems used for invasive blood pressure measurement
    (1989) Heimann, P A; Murray, W B; Boonzaier, David; Murray, PW le Roux; Poluta, Mladen
    Direct measurement of blood pressure using a fluid-filled catheter and an electromechanical transducer is widely accepted in clinical practice. However, errors associated with the measurement are often not appreciated and these catheter-manometer systems are frequently unable to accurately reproduce applied pressures. To assess the accuracy of catheter-manometer systems used for invasive arterial blood pressure measurements, in vitro and in vivo evaluations were performed. The frequency response (described in terms of damped natural frequency and damping factor) for a variety of cannulae, pressure tubing and stopcocks (and combinations thereof) and their dependence on various parameters (catheter length, lumen diameter, fluid temperature and catheter material) were measured using an hydraulic pressure generator. The design and construction details of the pressure generator are presented. It was found that the damped natural frequency of the catheter-manometer system is directly proportional to lumen diameter of the pressure tubing/catheter. Furthermore, damping factor is inversely related to the damped natural frequency and stiffer catheter material (for identical radius ratios) results in higher damped natural frequency. Catheter length is inversely related to damped natural frequency and the resonant frequency decreases for an increase in fluid operating temperature. It was established that all catheter-manometer systems tested were under-damped (0.15 < β < 0.37) and that the damped natural frequency ranged from 10.5 Hz for 1500 mm to 27.0 Hz for pressure tubing of 300 mm in length. Furthermore, catheter-manometer systems which had pressure tubing in excess of 300 mm in length did not comply with the bandwidth requirements for accurate dynamic blood pressure measurement. For the in vivo assessment of the catheter-manometer system, the blood pressure waveform was analysed in the time and frequency domains. It was established that in 60 percent of the cases, the systolic pressure peak was higher when measured by a narrow bandwidth catheter-manometer system compared to that measured by a wide bandwidth system. Furthermore, values of dp/dt maximum were lower for wide bandwidth catheter-manometer systems than those measured by narrow bandwidth systems for heart rates above 90 beats per minute. In the frequency domain analysis, artifact was sometimes found to occur at frequencies higher than the bandwidth of the catheter-manometer system. This high frequency artifact was found to distort the blood pressure waveform and resulted in false high dp/dt and peak systolic pressures.
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    Evaluation of the competence and attitudes of primary care physicians towards information technology
    (2000) Vogelzang, Barnabas Heinrich; Boonzaier, David; Cook, Donald
    The aim of this project was to produce some principles that would assist software developers (SD's) in the design of software for South African general medical practitioners (GP's). The author wanted to give SD's a cognitive model of general medical practice in the hope that this will improve the relevancy of future medical software. This cognitive model is in the form of a set of principles that SD's can keep in mind when developing software for GP's. An evaluation was done of the attitudes and competence of GP's towards information technology. This was done via detailed telephonic interviews, which were analyzed in order to deduce these principles.
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    Implementing linguistic text anticipation in a writing device for the disabled
    (1989) Waller, Annalu; Boonzaier, David
    The advent of the microcomputer has provided the severely handicapped with the means to create text. Instead of using a keyboard, the disabled typist is able to scan and select linguistic items with an appropriate input switch. The resulting communication rate is, however, prohibitively slow for writing and impractical for conversation. A variety of techniques is used to improve this rate and range from static letter matrices to more sophisticated methods in which words and phrases are anticipated. Although many anticipatory methods claim to be linguistically based, most, if not all, depend solely on letter and word frequency statistics. A series of phonological rules can be used to anticipate the letter structure of most English words. This linguistically based system reflects a degree of "intelligence" not present in other anticipatory writing systems. To evaluate and compare the new system with several existing techniques in practice, a programmable evaluation system has been developed on an IBM-compatible personal computer using the Artificial Intelligence language, LISP. Different communication strategies are transcribed into rulebases which serve as input to the software. The core program then executes the particular system under consideration. Input text can be processed in either manual or simulation mode and an evaluation report is generated when the session ends. The characteristics of efficient communication systems are introduced as a basis for this dissertation, after which the development and application of a linguistic anticipatory writing system is described. The design of the evaluation software is documented and the successful implementation of the various communication systems is discussed.
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    Medical education and the importance of teaching medical teachers about teaching
    (1994) Kent, Athol Parkes; Parsons, Phillip; Boonzaier, David
    This is an overview of medical education today. It deals with tertiary education matters pertinent to medical schools in South Africa, the forces that will inevitably cause medical education to change and the responses of other countries to similar circumstances. These forces are medical, educational and political. The medical forces bringing about changes are concerned with the explosion in knowledge in the fields of medical facts, technologies, therapies and informatics. It is an ongoing educational problem as to how the burgeoning sciences can be balanced with the present call for the return to the humanities. Medical schools are being required, through their teaching and learning methodologies, to encourage the qualification of empathetic graduates with generalist (holistic) skills and attitudes to best serve their patients. Educational forces, in particular new curriculum strategies, will need to be explored to assist teachers and students to cope with the demands of communities and individuals for care with expertise. In many First World countries these demands have found expression in moves from Traditional to Innovative curricula. Fundamentally, Traditional schools teach normal Anatomy and Physiology first, then move to the abnormal, before students reach the Clinical Years where these "basic sciences" are applied. Innovative schools, on the other hand, employ Problem-Based Learning with Community-Orientation throughout their curricula, with early patient contact, horizontal and vertical integration of disciplines, group work and community interaction as crucial aspects of their students' learning. Supporters of the Innovative philosophy see as progressive the revising of Flexnerian notions of basic science building blocks, the debalkanising of instruction subject by subject and the motivational impetus achieved when learning takes place in context. Political factors can impinge on staff teaching and student learning by Governmental demands through statutory councils or through the power exerted by the universities. Macro politics dictate financial or other resources that are allocated and may in future directly influence what sort of doctor the various medical schools are expected to graduate. The politics of staffing the teaching institutions, the development of teachers, and the demographics of the student population raise important questions of direction and commitment, and may lead to new realignments. The recognition of the importance of teaching at a professional level is a crucial factor in educating students more appropriately. Teachers versed in the medical pedagogic process will be pivotal in producing a new breed of doctors. This new breed will not be expected to "know everything" but have a core knowledge carefully ascertained by each medical faculty and the ability to find information that is further required. Students will not be expected to acquire all the facts to sustain them through the rest of their professional lives, but to have enquiring minds and the motivation to continue their education, to satisfy their curiosity and provide improved patient care. Their skills in mastery of the behavioural sciences will be more pertinent than ever as preventative medicine becomes as important as curative. They will be expected to formulate ethical attitudes and provide leadership in community and individual dilemmas. These are challenges that will need to be faced critically by our medical teachers who are too often experts in content in ever-narrower sub-specialities. For these challenges to be met, teaching cannot be taken for granted, but must be viewed more seriously by the schools and changes made where appropriate. The University of Cape Town (UCT) has a considerable reputation in the quality of its medical graduates. However, for its medical faculty to remain in the forefront of medical education, it needs to reconsider the knowledge required, the skills and attitudes embodied in its graduates but, as importantly, it must take the lead in undergraduate training. The need for renewing strategies and the action required are the themes of this dissertation.
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    A microcomputer-based synthesis of Blissymbols from key components to facilitate language acquisition in severely disabled people
    (1991) Shalit, Ami; Boonzaier, David
    Blissymbolics is a semantically-based graphic language which was originally developed as universal channel of communication to promote world peace. Instead, this logical and unambiguous symbol system has been adopted as a communication-enhancement system for pre-reading non-speaking children, and it is now ranked as the most comprehensive and effective graphic system used within augmentative communication. Over the years, a number of multi-functional programmes designed to manipulate microcomputer- based assembly of Blissymbols have been developed. Although some of these applications have become rather popular, none of them is based on a mechanism which provides their users with a cognitive access to the stored symbol vocabulary. The present research was initiated and devised with an underlying goal to gain an insight into some of the most potent characteristics of Blissymbolics, and then, with the backing of the findings, offer a microcomputer-based interface featuring a cognitive technique designed to facilitate retrieval, manipulation, teaching and learning of Blissymbols.
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    The prevalence and rehabilitation needs of individuals with locomotor disability in Mitchell's Plain
    (1997) Coetzee, Lizmory Tandeke Fehrsen; Boonzaier, David
    Locomotor disability is a problem, reported prevalence ranging from 1% to 8.6%. Only a limited number of studies have been done in South Africa. They used different methodologies and definitions, thus leading to the variation in prevalence reported. A further factor influencing prevalence is that some locomotor disabilities are area-specific. This study aimed to determine the prevalence and rehabilitation needs of individuals with locomotor disability in Mitchell's Plain, for planning intervention strategies as part of this community based rehabilitation service. A cross sectional study design was employed. A stratified proportional cluster sampling technique was used to select 36 clusters resulting in a sample size of2424 people. Screening questions recommended by the WHO were used to identify people with impairments (Phase I). Further screening (Phase II), of those identified with impairments, using a questionnaire based on the ICIDH categories, identified people with disabilities. People with locomotor disabilities were grouped together and qualitative analysis through case studies was done on sub-groups where common themes manifested. 12.9% reported some form of impairment; 3.9% adults could be classified as having disabilities. Amongst adults with disabilities, 2.7% had locomotor disabilities. Consistent with the literature, disability increased with age, was more frequently reported amongst females, and was associated with lower socio-economic class. Multiple impairments were frequently reported, with the most common impairment being musculo-skeletal conditions. Use of health services occurred in the public sector with the local Day Hospital used as frequently as more distant tertiary hospitals. The study revealed the need for improved and accessible medical and rehabilitation services in the community. Their poor ability to integrate functionally and economically into the community, was reflected in the high proportion of people with mobility and occupational handicap categories. Low levels of education worsened the impact on occupational handicap. It was further evident that multiple impairments amongst the elderly lead to greater dependence of people with locomotor disability on their care-givers. Even though the need for assistive equipment was high, much of assistive equipment owned was not being used. A further handicapping factor for the disabled using assistive equipment was their environment which restricted the use of assistive equipment. High locomotor disability prevalence was confirmed in this study. Major unmet needs were identified in the handicap categories of physical mobility and economic self-sufficiency. Domiciliary based intervention was recommended as the most appropriate rehabilitative intervention for the severely physically disabled persons.
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    Text entry, analysis and correction help : assisting the disabled computer user with data entry
    (1990) Hirson, Guy; Hanmer, Lyn Avril; Boonzaier, David
    It was suggested several decades ago that computers would be the single biggest step forward in integrating people with physical disabilities into "normal" society. At that stage, much work was done in writing software and designing hardware that allowed computer operators with disabilities to use packages effectively, in certain cases as efficiently as people without disabilities. Since those days, judging by the lack of references on this subject the interest in dealing with disabled people has waned. It is only very recently that the spotlight has been focused on these potentially very productive persons. Unfortunately, the backlog is large and most existing applications software offers little or no support for users with disabilities. In this thesis, I have examined some of the hardware and software limitations of current desktop computer technology, focusing on the IBM PC and compatibles. I have also written a computer program that attempts to relieve some of the difficulties faced by a limited number of disabled users. In evaluating the results, I considered it important to relate the ensuing data with the real problems faced by a far wider spectrum of users than I attempted to cater for with the program and to suggest ways in which software products could be made to have wider applicability in the future.