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    Open Access
    The effective power output of the Taurus 301 blood warmer when warming small volume units of red cell concentrate described using simulated blood products
    (2023) Eave, Dylan; Coetzee, Ettienne
    Background and Literature review At Groote Schuur Hospital, the lead anaesthesiologist in the cardiothoracic team, J. Ozinsky, identified the need for a device capable of warming blood rapidly prior to transfusion. Such a device was subsequently developed as a collaborative effort between the Department of Anaesthetics and Department of Electrical Engineering at the University of Cape Town. The device became known as the “Taurus” blood warmer, namesake of the Head of Department at the time, and clinical leader of the project, Prof. A.B. Bull. A subsequent version of the Taurus, which warms blood within the bag in which it is packaged, remains in active clinical service at Groote Schuur Hospital. Literature search reveals that devices which employed electromagnetic radiation for warming of blood and blood products were met with resistance following many case reports of haemolysis induced by warming. A common theme identified was that of elevated risk of haemolysis, due to local overheating, in blood products of high haematocrit (HCT) and small volume. The Taurus 301 performance has been evaluated extensively and the device used for over 30 years. Without any literature available to suggest that the device is overtly harmful it may be concluded that the device design is one that may be drawn upon with confidence especially for these blood products at elevated risk of haemolysis. The Taurus range of blood warmers represent the only examples of a radio-frequency blood warmers that were made available commercially for clinical use. In 1996 fire swept through the factory responsible for manufacture of Taurus blood warmers. Taurus manufacturing capability was not restored and more than a quarter century has now passed since the last Taurus 301 was commissioned. Taurus devices may still be found in active service within some South African hospitals.(1) The author has also observed the scrapping of at least 3 units from the Groote Schuur Hospital Complex over the past 5 years and, if the situation parallels that of other hospitals, the Taurus may soon be lost to clinical practice. Research questions The mean effective power output of the Taurus 301, when used for the warming of small volume units of red cell concentrate, in the setting of massive transfusion, prior to this study, was unknown. The primary aim of this study was to describe the mean effective power output of the Taurus 301 in this context. To realise this aim, four identical bags of simulated, small volume, red cell concentrate were prepared and cooled to 4 oC before being warmed sequentially using a Taurus 301 which remains in active service. For each warming instance calorimetry was used to determine effective power output of the device. The bags were thereafter again cooled to 4 oC and 24 such warming instances undertaken. It was also unknown whether or not the increase in effective power output observed for bags warmed serially, in the Taurus 301, is significant. The secondary aim of this study was to determine the extent and significance of this increase. This secondary aim was achieved by means of subgroup analysis in which comparison was made between effective power output 11 observed for bags warmed as a function of sequence within a batch of serial warming instances. Methods For the purposes of evaluating the warming performance of an electromagnetic blood warming device, concentrations of saline may be used to simulate the electrical properties of specific blood products. The interaction between blood and electromagnetic radiation has been exhaustively studied and these data made available. Perusal of these data will reveal, among other properties, the conductivity of blood for a range of haematocrit values, temperatures and electromagnetic field frequencies. Using these data, and that of saline solutions, a saline-based blood product simulation is possible. The experiment was conducted within a laboratory adjacent to the main theatre complex at 2 Military Hospital, a tertiary-level hospital in Cape Town, South Africa, where there remains a functional Taurus 301 blood warmer. This particular Taurus 301 is functional and used regularly for the warming of red cell concentrates. Four simulated bags of red cell concentrate of small volume served as subjects for the experiment. These four bags underwent cycles of cooling and then warming, using the Taurus 301. Results The Taurus 301 mean effective power output, when considering all warming instances, was 172.04 W (n = 96; 95% CI 169.61 – 174.47). A mean effective power output of 153.11 W (n=24; 95% CI 151.37 – 154.85) and 181.61 W (n=24; 95% CI 179.95 – 183.26) was observed when warming the first bag and last bag in each batch respectively. Taurus maximum power output was thus seen to be observed during warming of the last bag in a batch. When considering the difference in effective power output between bags warmed first and those warmed subsequently, a statistically significant increase in mean power of 25.25W (p <0.001; 95% CI 23.00 to 27.49) was observed. Conclusion This research has determined the mean maximum effective power output of Taurus 301, when used to warm the most vulnerable of blood product units, to be 181.61 W (n=24; 95% CI 179.95 – 183.26), and makes this value known in the interests of providing insight into what is likely a safe power output target for a prototype modernised Taurus.
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    Open Access
    Twelve Month outcome analysis of a South African Intensive Care Unit.
    (2023) Erwee, Daniel; Piercy, Jenna
    Abstract Background: The description of outcomes after admission to Critical Care Units in Africa is sparse, reporting mortality rates between 23.6% and 53.6%. South African data, thus far, show in-ICU mortality rates between 9% and 19.7%. To our knowledge, no evaluation of ICU outcomes has ever been performed on a population group in the Western Cape Province. Objectives: To describe patients admitted to an 8-bed ICU unit over one calendar year with regards to demographics and outcomes situated in Groote Schuur Hospital with regard to inICU and 1-year mortality rates. Methods: This is a retrospective descriptive review of adult patients (>18 years old) from 1 January 2019 to 31 December 2019. Data were collected on age, sex, primary admission diagnosis, length of stay and mortality. Results: A total of 338 patients were included; 61.2% (n=207) with a primary medical diagnosis and 38.2% (n=129) with a non-medical diagnosis. Trauma accounted for 13.6% of all admissions. The burden of known HIV infection as a comorbidity was 16.9% (n=57). The overall in-ICU mortality rate was 25.7% (n=87), and the one-year mortality rate was 18.0% (n=25), but with a significant loss to follow-up of 33.1%. Conclusion: The overall in-ICU mortality was 25.7%. A large proportion of patients admitted had a trauma diagnosis, despite it historically accepting mostly medical and complicated obstetric patients.
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    Open Access
    Exploring the disintermediation effect of blockchain technology on the tourism industry
    (2023) Faker, Imaan; Budree, Adheesh
    Researchers and practitioners believe that blockchain technology (BCT) will have a substantial impact on all industries, including the tourism industry. Blockchain technology is open-source software that allows the creation of an immutable, distributed ledger (record of transactions). One of the immediate effects recognized by researchers in this domain is that blockchain technology has the potential to remove intermediaries such as Online Travel Agencies (OTA's) and Global Distribution Systems (GDS), thereby disrupting the industry as it stands. This is known as the disintermediation effect. This domain is largely regarded to be in its infancy at both practical and academic levels, hence several researchers are calling for a more systematic and rigorous approach to have a big impact on the development process of this technology for the tourism industry. To address this request, this qualitative study explores disintermediation as a core characteristic and effect of applying blockchain technology to the travel industry. This research aims to strengthen already scarce research in this domain, and thereby move forward blockchain tourism research. It employs a case study design guided by a blockchain-based framework which specifies five factors necessary for an increased level of disintermediation. A modified version of the framework is presented as findings reveal that intermediaries are becoming more innovative in entering the blockchain market, and therefore further sub-factors can be identified based on how disintermediation is currently being introduced in this industry. Keywords: blockchain technology; travel and tourism; disintermediation; intermediaries; online travel.
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    Open Access
    Evaluation of the elephant immunocontraception program at Hluhluwe-iMfolozi Park, South Africa
    (2023) Fagan, Emma; Bishop, Jacqueline
    Managing African savannah elephant (Loxodonta africana) overpopulation in enclosed reserves is currently a major issue in southern Africa due to the potential negative impact of high elephant density on biodiversity. Immunocontraception of elephants has been proven to be an effective method of population control on small reserves with populations of less than 250 individuals, but there is uncertainty regarding its application in larger populations. South Africa's Hluhluwe-iMfolozi Park (HiP), with over 700 elephants, started a porcine zona pellucida (pZP) immunocontraception program in 2014 with the aim of reducing the population growth rate from 7.7% (2014-2016) to between 2 and 3%, but the program has not yet been formally assessed. In this study, I aimed to (1) evaluate the effectiveness of the 8-year program at the park, by measuring its effect on the population growth rate, and (2) explore potential factors affecting contraception efficacy. The proportion of infants within breeding herds was used to estimate growth rate. The proportion was determined using on-the- ground observations of breeding herds collected during six weeks of fieldwork in October and November 2022 and compared to previous years. The infant proportion in breeding herds and population growth rate were estimated as 0.156 and 7.16% respectively, only slightly less than the 2016 values of 0.167 and 7.7%. A critical assessment suggests that the key reasons for reduced contraception efficacy are consistency of individuals being contracepted and population coverage of breeding-age females. Approximately 75% of all reproductive-age females in the park are associated with collared herds (GPS collars are used to help locate herds for darting), but herd size variation due to fission-fusion social dynamics limited the role of collars in improving efficacy. An average 14% of reproductive-age females were missed each year due to failure to locate some collared herds. Despite high annual coverage of females in any one year, the estimated probability of a reproductive-age female being darted consistently (every year) between 2018 and 2022 was estimated at only 0.355 due to multiplied probability effects. Records also suggest that HiP has been significantly under- darting every year, except for 2022, due to inaccurate darting targets. That this program has not reduced the growth rate as planned suggests that the use of porcine zona pellucida (pZP) immunocontraception in larger elephant populations may be limited by important practical aspects of implementing and maintaining the number of contracepted females. Further research is required to assess its potential at the scale of populations such as HiP's elephants, which currently totals an estimated 1100 individuals. Given the management goals of the program, HiP will need to consider whether to continue the program with adjustments to improve efficacy or explore other options to manage overpopulation, especially in the short term. Keywords: Loxodonta africana, immunocontraception, porcine zona pellucida, overpopulation
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    Open Access
    A Critical Evaluation of the Use of Crack Width Requirements in the Durability Design of Marine Reinforced Concrete Structures
    (2023) Elias, Nicholas; Beushausen, Hans-Dieter
    Crack width requirements (CWRs), which aim to limit cracks in reinforced concrete (RC) to maximum prescribed values, play a major – and often dominant – role in the design of marine RC structures. However, there are several issues with the current CWRs, chief among which is the fact that, despite decades of research, no clear relationship between crack width and steel reinforcement corrosion rate in concrete has been found. Instead, there exist two opposing schools of thought in the literature – one which says that there is a relationship between crack width and reinforcement corrosion rate, and one which argues that no such relationship exists – with good evidence to support both schools of thought. Recent research has shown that even small cracks, with widths below the required values, may lead to extensive corrosion. It is therefore uncertain whether designing for the CWRs actually improves durability and extends the service life of marine RC structures. Furthermore, the use of the CWRs, which frequently results in large increases in the required amount of reinforcing steel, may lead to significant increases in the cost and environmental impact of marine RC structures. Yet, to date, these impacts have not been quantified. In order to address these issues, this study was aimed at evaluating the effect of designing to meet the current CWRs on the durability, cost, and environmental sustainability of marine RC structures. This was done by designing two sets – one with, and one without the CWRs – of typical marine RC structural elements. Based on real industry projects, two different types of elements were designed – a crane rail beam for a coal export jetty in Matola, Mozambique, and a precast crown wall unit for a breakwater in Rupert's Bay, St. Helena Island. The designs were carried out using a combination of BS 6349 and EN 1992-1-1:2004, as these are the codes of practice typically used in the South African coastal engineering industry. The effects of designing for the current CWRs on durability, cost, and environmental sustainability were then quantified by carrying out service life modelling, life cycle cost assessments (LCCAs) and estimating embodied carbon (EC) values for the designed members. The results of the service life modelling show that, for the range of crack widths likely to occur in practice, the use of the current CWRs does not improve durability, and may even reduce service life, as they encourage the use of more, smaller diameter reinforcement bars, which has the effect of increasing corrosion rate and reducing the time taken for a critical amount of the reinforcement to be lost due to corrosion. Furthermore, the results of the LCCA and EC estimates imply that the current CWRs are not the most cost-effective method for durability design and may result in significant increases in cost and environmental impact. Taken together, these results suggest that, even if a relationship is assumed to exist between crack width and corrosion rate, the current CWRs are neither the most effective, nor efficient way of addressing the effects of cracking on the durability of marine RC structures. It is therefore recommended that the current crack width requirements should be removed from the durability design codes of practice and replaced with either a limitation on steel stress, a more lenient crack width requirement (for example, of 0.5 mm rather than 0.3 mm), or a performance-based crack width requirement, which takes better account of the complexity of cracking and its effect on durability. It is also recommended that engineers be given the option to use other methods of providing durability, such as the use of crack-sealing and waterproofing admixtures, or hydrophobic treatments, instead of the current CWRs. However, before any of these recommendations can be implemented, the results of this study need to be confirmed with further research. Owing to the limitations of both service life modelling and accelerated laboratory corrosion, it is recommended that this further research should take the form of an extensive evaluation of the durability performance of existing marine RC structures.