An unusual case of acute pulmonary embolism

Patiant with a history of hypertension presented to the emergency room with progressive dyspnoea over afew weeks. There was no relevant past history. Clinical examination revealed an elevated jugular venous pressure, pedal oedema and tenderness in the right hypochondrium

Opportunities to optimise colistin stewardship in hospitalised patients in South Africa: Results of a multisite utilisation audit

Background. Colistin is an old antibiotic that has been reintroduced as salvage therapy in hospitalised patients because it is frequently the only agent active against Gram-negative bacteria. Various guidelines for colistin administration have led to confusion in establishing the appropriate dose, which has potential for adverse consequences including treatment failure or toxicity. The emergence and spread of colistin resistance has been documented in South Africa (SA), but no local information exists on how and why colistin is used in  hospitals, and similarly, compliance with current dosing guidelines is unknown.Objectives. To evaluate the current utilisation of colistin in SA hospitals, in order to identify stewardship opportunities that could enhance the appropriate use of this antibiotic.Methods. Electronic patient records of adult patients on intravenous (IV) colistin therapy for >72 hours in four private hospitals were retrospectively audited over a 10-month period (1 September 2015 - 30 June 2016). The following data were recorded: patient demographics, culture and susceptibility profiles, diagnosis, and indication for use. Compliance with six colistin process measures was audited: obtaining a culture prior to initiation, administration of a loading dose, administration of the correct loading dose, adjustments to maintenance dose according to renal function, whether colistin was administered in combination with another antibiotic, and whether de-escalation following culture and sensitivity results  occurred. Outcome measures included effects on renal function, overall hospital mortality, intensive care unit length of stay (LoS), and hospital LoS.Results. Records of 199 patients on IV colistin were reviewed. There was 99.0% compliance with obtaining a culture prior to antibiotic therapy, 93.5% compliance with prescription of a loading dose, and 98.5% compliance regarding prescription of colistin in combination with another agent. However, overall composite compliance with the six colistin stewardship process measures was 82.0%. Non-compliance related to inappropriate loading and  maintenance doses, lack of adjustment according to renal function and lack of de-escalation following culture sensitivity was evident. Significantly shorter durations of treatment were noted in patients who received higher loading doses (p=0.040) and in those who received maintenance doses of 4.5 MU twice daily v. 3 MU three times daily (p=0.0027). In addition, compared with patients who survived, more patients who died received the 3 MU three times daily maintenance dose (p=0.0037; phi coefficient 0.26).Conclusions. The study identified multiple stewardship opportunities to optimise colistin therapy in hospitalised patients. Urgent implementation of a stewardship bundle to improve colistin utilisation is warranted.

Gas turbine combustion instability

Combustion oscillations are a common problem in development of LPM (lean premix) combustors. Unlike earlier, diffusion style combustors, LPM combustors are especially susceptible to oscillations because acoustic losses are smaller and operation near lean blowoff produces a greater combustion response to disturbances in reactant supply, mixing, etc. In ongoing tests at METC, five instability mechanisms have been identified in subscale and commercial scale nozzle tests. Changes to fuel nozzle geometry showed that it is possible to stabilize combustion by altering the timing of the feedback between acoustic waves and the variation in heat release

METC Combustion Research Facility

The objective of the Morgantown Energy Technology Center (METC) high pressure combustion facility is to provide a mid-scale facility for combustion and cleanup research to support DOE`s advanced gas turbine, pressurized, fluidized-bed combustion, and hot gas cleanup programs. The facility is intended to fill a gap between lab scale facilities typical of universities and large scale combustion/turbine test facilities typical of turbine manufacturers. The facility is now available to industry and university partners through cooperative programs with METC. Currently two combustion rigs are operating and one additional project is under construction for the facility. Space is available in the test cells for at least one additional test rig. A pressurized pulsed combustor began operating in July of 1993. The combustor will carry out pulsed combustion of natural gas at pressures up to 10 atmospheres. A high pressure steady flow rig is currently completely fabricated. The objective of this rig is to test novel, steady-flow, pressurized combustors that produce very low NO{sub x} and other emissions. An evaporation rig currently is in startup. This rig will test the concept of water injection in an externally fired cycle. The specific technical issue that the unit will address is evaporation rates of water droplets in high pressure flows

Editorials

Continuing medical education in obstetrics and gynaecologyThe present and future of obstetrics and gynaecology in South AfricaThe case for an increased tobacco tax in South AfricaImplications of bacterial resistance for the use of beta-lactam agents in clinical practiceQuality of care - and debateAlcohol and brain damag

Changes in body composition after thermal injury in the rat.

1. The effects on body composition, measured by direct techniques, of a controlled 25% body-surfacearea thermal injury have been studied in two groups of forty male Wistar rats. 2. The extent of weight loss in the animals was directly related to their energy deficit resulting from a combination of injury, food intake and rate of wound healing. 3. Body fat proved the most labile source of tissue energy, decreasing to a minimum of approximately 30 g/kg body-weight. 4. Relationships between water and fat, and water and protein seen in control animals were not significantly different in the traumatized group

Combustion of Coal Using Chemical Looping Oxygen Carriers

Slide presentation only - No abstract supplie

Antiretroviral therapy non-adherence among HIV- positive patients presenting to an emergency department in Johannesburg, South Africa: associations and reasons

BACKGROUND. Suboptimal antiretroviral therapy (ART) adherence is associated with viral resistance, opportunistic infections and increased mortality. OBJECTIVES. To determine the rates of ART non-adherence and its associations, and also the reasons for ART non-adherence, among HIV-positive patients presenting to a major central hospital emergency department (ED). METHODS. Consecutive HIV-positive patients presenting to the Charlotte Maxeke Johannesburg Academic Hospital adult ED between 7 July 2017 and 18 October 2018 were prospectively enrolled. Self-reported adherence was assessed using the AIDS Clinical Trials Group Adherence Questionnaire (ACTG-AQ). RESULTS. Of the 1 224 consecutive HIV-positive participants enrolled, 761 (75.2%) were on ART at the time of ED presentation. Of these, 245 (32.2%) were non-adherent as per the ACTG-AQ. Participants not yet on ART prior to ED presentation had significantly higher in-hospital mortality than participants on ART (odds ratio 1.69; 95% confidence interval 1.21 - 2.34; p=0.002). Younger age, male sex, CD4 count <100 cells/µL, lack of viral suppression, a high National Early Warning Score 2 (≥7 points) and length of hospital stay ≥7 days were significantly associated with ART non-adherence (p<0.05). Forgetfulness (13.9%) and lack of social support, depression/stress/mental illness, and lack of money for transport to collect medications (9.9% each) were the most common reasons given for ART non-adherence. CONCLUSIONS. Of HIV-positive patients presenting to the ED, a high proportion were either not yet initiated on ART or ART non-adherent. HIV programmes should focus on HIV-positive ED attendees with the aim of identifying high-risk patients and providing adequate ART adherence supporthttp://www.samj.org.zadm2022Critical Car

Combustion oscillation control by cyclic fuel injection

A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle/combustor arrangement. The fuel is natural gas. Cyclic injection of 14% control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {approximately}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported

Combustion Oscillation Control by Cyclic Fuel Injection

A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle/combustor arrangement. The fuel is natural gas. Cyclic injection of 14% control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {approximately}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported