Distal renal tubular acidosis in a patient with Hashimoto's thyroiditis: a case report.

Renal tubular acidosis (RTA) is a rare disorder that can be inherited or acquired, and results in an inability of the kidneys to maintain normal acid-base balance. We present a case of recurrent, severe hypokalaemia and rhabdomyolysis in a young woman who had an associated normal anion gap metabolic acidosis and was subsequently diagnosed with distal RTA associated with Hashimoto's thyroiditis. Distal RTA associated with Hashimoto's thyroiditis is rare and probably develops because of autoimmune-mediated mechanisms, causing an inability of the H+-ATPase pump in alpha-intercalated cells of the cortical collecting duct to secrete H+, with subsequent failure of urinary acidification. In this case, this hypothesis was supported by the exclusion of common genetic mutations associated with distal RTA. We illustrate that utilizing a systematic, physiology-based approach for challenging electrolyte and acid-base disorders enables identification of the root cause and underlying disease mechanisms.

The frequency of acid-base disorders on admission to the intensive care and its association with in-hospital outcome, Cape Town, South Africa: a retrospective cohort study.

Introduction: acid-base disorders are very common in critically ill patients and contribute significantly to morbidity and mortality. The aim of this study was to identify the types of acid-base disorders at the time of admission to the intensive care unit (ICU) and its associated ICU and in-hospital mortality. Methods: we conducted a retrospective cohort study of all adult patients that were admitted to the ICU and had an arterial blood gas sample at the time of admission from 1st January 2019 to 31 December 2019. Using the traditional approach, acid-base disorders were categorised into six disorders. Variables predicting in-hospital death were identified using logistic regression. Results: a total of 375 patients were included. The median age for the entire cohort was 39 (IQR 30-52) years and 48.3% (n=181) were female. Mixed acid-base disorders were the most common at 48.8% (n=183), followed by no disorder at 24.8% (n=93), metabolic acidosis at 9.3% (n=35), metabolic alkalosis at 6.7% (n=25), respiratory acidosis 6.1% (n=23) and respiratory alkalosis at 4.3% (n=16). A total of 94 (25.0%) patients died. There were no differences in ICU (p = 0.35) or in-hospital death (p = 0.32) by acid-base disorder. Male sex (aOR: 5.8, 95% CI 1.55-21.42; p < 0.01), APACHE II score (aOR: 1.17, 95% CI 1.06-1.30; p < 0.01) and the corrected anion gap (aOR: 1.14, 95% CI 1.02-1.27; p = 0.02) were identified as predictors of in-hospital death using multivariable logistic regression. Conclusion: there was no association between acid-base disorders at the time of ICU admission and ICU or in-hospital death. Therefore, in our setting, acid-base disorders at the time of ICU admission should not be used to predict the outcome of patients requiring intensive care.

Outcomes of hospitalised patients with hyperkalaemia at a South African tertiary healthcare centre.

Background: Hyperkalaemia is a common electrolyte disorder in hospitalised patients. There is a lack of data from Africa on the prevalence, causes and outcomes of patients with hyperkalaemia. We aimed to identify the frequency of hyperkalaemia in hospitalised adults, and to identify any risk factors for in-hospital death. Methods: We conducted a retrospective cohort study of 1921 adult patients admitted to hospital with hyperkalaemia (potassium concentration ([K]) ≥ 5·5 mmol/L) over a one-year period during 2019. Multivariable logistic regression was performed to identify predictors of in-hospital mortality and multilinear regression was used to identify associations with the [K]. Findings: We found an incidence rate of 3·7 cases per 100 patient-years. Nearly a third died during hospitalisation. Acute kidney injury (AKI) was common in patients who died (69·2% vs. 41·3%, P < 0·01). Age (odds ratio (OR) 1·02, 95% CI 1·01-1·03), [K] (OR 1·38, 95% CI 1·12-1·71), AKI (OR 3·13, 95% CI 2·19-4·47) and acute therapy (OR 1·93, 95% CI 1·40-2·66) were predictors of in-hospital death. AKI (r = 0·29, P < 0·01) and chronic kidney disease (r = 0·31, P < 0·01) were associated with the [K]. Fourteen percent of patients with hyperkalaemia were HIV positive with no difference in in-hospital death (P = 0·75). Interpretation: This is the largest study reporting on the epidemiology of hyperkalaemia in hospitalised adults from Africa. Hyperkalaemia in association with AKI was a strong predictor of in-hospital death. Late presentation to hospital may be a major factor contributing to poor outcomes. Funding: Self-funded.

Hypoglycaemia due to insulin therapy for the management of hyperkalaemia in hospitalised adults: A scoping review.

INTRODUCTION: Hyperkalaemia is a very common electrolyte disorder encountered in hospitalised patients. Although hypoglycaemia is a frequent complication of insulin therapy, it is often under-appreciated. We conducted a scoping review of this important complication, and of other adverse effects, of the treatment of hyperkalaemia in hospitalised adults to map existing research on this topic and to identify any knowledge gaps. MATERIALS AND METHODS: We followed the PRISMA-ScR guidelines. Studies were eligible for inclusion if they reported on any adverse effects in hospitalised patients ≥18-years-old, with hyperkalaemia receiving treatment that included insulin. All eligible research from 1980 to 12 October 2021 were included. We searched Medline (PubMed), Embase (Ovid), the Cochrane Library, CINHAL, Africa-Wide Information, Web of Science Core Collection, LILACS and Epistemonikos. The protocol was prospectively registered with the Open Science Framework (https://osf.io/x8cs9). RESULTS: Sixty-two articles were included. The prevalence of hypoglycaemia by any definition was 17.2% (95% CI 16.6-17.8%). The median timing of hypoglycaemia was 124 minutes after insulin administration (IQR 102-168 minutes). There were no differences in the prevalence of hypoglycaemia when comparing insulin dose (<10 units vs. ≥10 units), rate of insulin administration (continuous vs. bolus), type of insulin (regular vs. short-acting) or timing of insulin administration relative to dextrose. However, lower insulin doses were associated with a reduced prevalence of severe hypoglycaemia (3.5% vs. 5.9%, P = 0.02). There was no difference regarding prevalence of hypoglycaemia by dextrose dose (≤25 g vs. >25 g); however, prevalence was lower when dextrose was administered as a continuous infusion compared with bolus administration (3.3% vs. 19.5%, P = 0.02). The most common predictor of hypoglycaemia was the pre-treatment serum glucose concentration (n = 13 studies), which ranged from < 5.6-7.8 mmol/L. CONCLUSION: This is the first comprehensive review of the adverse effects following insulin therapy for hyperkalaemia. Hypoglycaemia remains a common adverse effect in hospitalised adults. Future randomised trials should focus on identifying the optimal regimen of insulin therapy to mitigate the risk of hypoglycaemia.

How common is hyperkalaemia? A systematic review and meta-analysis of the prevalence and incidence of hyperkalaemia reported in observational studies.

Background: The prevalence and incidence of hyperkalaemia, a potassium abnormality that can potentially have life-threatening consequences, are unclear. Methods: The objective was to provide the most comprehensive overview of the epidemiology of hyperkalaemia to date within the general population, across different continents, in different healthcare settings and within pre-specified subgroups. Embase and MEDLINE were searched from database inception to 2 February 2021 using the Ovid SP platform. Relevant congress proceedings from 2018 to 2020 were also reviewed for inclusion. There was no language constraint applied. Observational studies from any time period and language reporting prevalence or incidence of hyperkalaemia within both adult and paediatric populations. Four investigators independently screened abstracts and assessed study quality of those meeting the pre-determined inclusion/exclusion criteria. Data extraction was conducted by the lead author with oversight from the senior author and data were pooled using a random-effects model. The measures assessed were the prevalence and incidence of hyperkalaemia. Prevalence was reported as a percentage, whilst incidence was reported as the rate per 100 person years. Results: In total, 542 articles were included from an initial search of 14 112 articles. Across all adult studies, we report a prevalence of hyperkalaemia (by any definition/threshold) of 6.3% [95% confidence interval (CI): 5.8-6.8%], with an incidence of hyperkalaemia in the adult population of 2.8 (2.3-3.3) cases per 100 person years. Prevalence within the general population was 1.3% (1.0-1.8%), whilst incidence was 0.4 (0.2-0.8) cases per 100 person years. There was a variation by sex with a prevalence of 6.3% (4.9-8.0%) in males and 5.1% (4.0-6.6%) in females. Prevalence also varied according to the definition/threshold of hyperkalaemia used: >5 mmol/L-8.0% (7.2-8.9), ≥5.5 mmol/L-5.9% (3.5-10.0) and ≥6.0 mmol/L-1.0% (0.8-1.4); hyperkalaemia (by any definition/threshold) was highest amongst patients with end-stage kidney disease (21.5%; 18.3-25.3), kidney transplant patients (21.8%; 16.1-29.5) and patients with acute kidney injury (24.3%; 19.3-30.7). Conclusions: This novel review provides a comprehensive and valuable resource on the prevalence and incidence of hyperkalaemia to better inform clinicians, healthcare providers and health policy makers on the burden of hyperkalaemia across different healthcare settings, patient populations and continents.

COVID-19 and kidney disease: insights from epidemiology to inform clinical practice.

Over the course of the COVID-19 pandemic, numerous studies have aimed to address the challenges faced by patients with kidney disease and their caregivers. These studies addressed areas of concern such as the high infection and mortality risk of patients on in-centre haemodialysis and transplant recipients. However, the ability to draw meaningful conclusions from these studies has in some instances been challenging, owing to barriers in aspects of usual care, data limitations and problematic methodological practices. In many settings, access to SARS-CoV-2 testing differed substantially between patient groups, whereas the incidence of SARS-CoV-2 infection varied over time and place because of differences in viral prevalence, targeted public health policies and vaccination rates. The absence of baseline kidney function data posed problems in the classification of chronic kidney disease and acute kidney injury in some studies, potentially compromising the generalizability of findings. Study findings also require attentive appraisal in terms of the effects of confounding, collider bias and chance. As this pandemic continues and in the future, the implementation of sustainable and integrated research infrastructure is needed in settings across the world to minimize infection transmission and both prevent and plan for the short-term and long-term complications of infectious diseases. Registries can support the real-world evaluation of vaccines and therapies in patients with advanced kidney disease while enabling monitoring of rare complications.

Trends in the nephrologist workforce in South Africa (2002-2017) and forecasting for 2030.

BACKGROUND: The growing global health burden of kidney disease is substantial and the nephrology workforce is critical to managing it. There are concerns that the nephrology workforce appears to be shrinking in many countries. This study analyses trends in South Africa for the period 2002-2017, describes current training capacity and uses this as a basis for forecasting the nephrology workforce for 2030. METHODS: Data on registered nephrologists for the period 2002 to 2017 was obtained from the Health Professions Council of South Africa and the Colleges of Medicine of South Africa. Training capacity was assessed using data on government-funded posts for nephrologists and nephrology trainees, as well as training post numbers (the latter reflecting potential training capacity). Based on the trends, the gap in the supply of nephrologists was forecast for 2030 based on three targets: reducing the inequalities in provincial nephrologist densities, reducing the gap between public and private sector nephrologist densities, and international benchmarking using the Global Kidney Health Atlas and British Renal Society recommendations. RESULTS: The number of nephrologists increased from 53 to 141 (paediatric nephrologists increased from 9 to 22) over the period 2002-2017. The density in 2017 was 2.5 nephrologists per million population (pmp). In 2002, the median age of nephrologists was 46 years (interquartile range (IQR) 39-56 years) and in 2017 the median age was 48 years (IQR 41-56 years). The number of female nephrologists increased from 4 to 43 and the number of Black nephrologists increased from 3 to 24. There have been no nephrologists practising in the North West and Mpumalanga provinces and only one each in Limpopo and the Northern Cape. The current rate of production of nephrologists is eight per year. At this rate, and considering estimates of nephrologists exiting the workforce, there will be 2.6 nephrologists pmp in 2030. There are 17 government-funded nephrology trainee posts while the potential number based on the prescribed trainer-trainee ratio is 72. To increase the nephrologist density of all provinces to at least the level of KwaZulu-Natal (2.8 pmp), which has a density closest to the country average, a projected 72 additional nephrologists (six per year) would be needed by 2030. Benchmarking against the 25th centile (5.1 pmp) of upper-middle-income countries (UMICs) reported in the Global Kidney Health Atlas would require the training of an additional eight nephrologists per year. CONCLUSIONS: South Africa has insufficient nephrologists, especially in the public sector and in certain provinces. A substantial increase in the production of new nephrologists is required. This requires an increase in funded training posts and posts for qualified nephrologists in the public sector. This study has estimated the numbers and distribution of nephrologists needed to address provincial inequalities and achieve realistic nephrologist density targets.

COVID-19 Pandemic: Is Africa Different?

COVID-19 has now spread to all the continents of the world with the possible exception of Antarctica. However, Africa appears different when compared with all the other continents. The absence of exponential growth and the low mortality rates contrary to that experienced in other continents, and contrary to the projections for Africa by various agencies, including the World Health Organization (WHO) has been a puzzle to many. Although Africa is the second most populous continent with an estimated 17.2% of the world's population, the continent accounts for only 5% of the total cases and 3% of the mortality. Mortality for the whole of Africa remains at a reported 19,726 as at August 01, 2020. The onset of the pandemic was later, the rate of rise has been slower and the severity of illness and case fatality rates have been lower in comparison to other continents. In addition, contrary to what had been documented in other continents, the occurrence of the renal complications in these patients also appeared to be much lower. This report documents the striking differences between the continents and within the continent of Africa itself and then attempts to explain the reasons for these differences. It is hoped that information presented in this review will help policymakers in the fight to contain the pandemic, particularly within Africa with its resource-constrained health care systems.

Survival of South African patients on renal replacement therapy.

BACKGROUND: The majority of South Africans rely on a resource-constrained public healthcare sector, where access to renal replacement therapy (RRT) is strictly rationed. The incidence of RRT in this sector is only 4.4 per million population (pmp), whereas it is 139 pmp in the private sector, which serves mainly the 16% of South Africans who have medical insurance. Data on the outcomes of RRT may influence policies and resource allocation. This study evaluated, for the first time, the survival of South African patients starting RRT based on data from the South African Renal Registry. METHODS: The cohort included patients with end-stage kidney disease who initiated RRT between January 2013 and September 2016. Data were collected on potential risk factors for mortality. Failure events included stopping treatment without recovery of renal function and death. Patients were censored at 1 year or upon recovery of renal function or loss to follow-up. The 1-year patient survival was estimated using the Kaplan-Meier method and the association of potential risk factors with survival was assessed using multivariable Cox proportional hazards regression. RESULTS: The cohort comprised 6187 patients. The median age was 52.5 years, 47.2% had diabetes, 10.2% were human immunodeficiency virus (HIV) positive and 82.2% had haemodialysis as their first RRT modality. A total of 542 patients died within 1 year of initiating RRT, and overall 1-year survival was 90.4% [95% confidence interval (CI) 89.6-91.2]. Survival was similar in patients treated in the private sector as compared with the public healthcare sector [hazard ratio 0.93 (95% CI 0.72-1.21)]. Higher mortality was associated with older age and a primary renal diagnosis of 'Other' or 'Aetiology unknown'. When compared with those residing in the Western Cape, patients residing in the Northern Cape, Eastern Cape, Mpumalanga and Free State provinces had higher mortality. There was no difference in mortality based on ethnicity, diabetes or treatment modality. The 1-year survival was 95.9 and 94.2% in HIV-positive and -negative patients, respectively. One-fifth of the cohort had no data on HIV status and the survival in this group was considerably lower at 77.1% (P < 0.001). CONCLUSIONS: The survival rates of South African patients accessing RRT are comparable to those in better-resourced countries. It is still unclear what effect, if any, HIV infection has on survival.

Human resources for nephrology in South Africa: A mixed-methods study.

INTRODUCTION: The global nephrology workforce is shrinking and, in many countries, is unable to meet healthcare needs. Accurate data pertaining to human resources in nephrology in South Africa is lacking. This data is critical for the planning and delivery of renal services and the training of nephrologists in South Africa to meet the challenge of the growing burden of chronic kidney disease. METHODS: A cross-sectional study of adult and paediatric nephrologists currently delivering nephrology services in South Africa was conducted. Participants were identified using various data sources, including the register of the Health Professions Council of South Africa. This cohort of doctors was described in terms of their demographics and distribution. A survey was then conducted among these nephrologists to collect additional information on their training, scope of practice, job satisfaction, challenges and future plans. Finally, two focus group interviews were conducted to probe themes identified from the survey data. RESULTS: A total of 120 adult nephrologists and 22 paediatric nephrologists were identified (an overall density of 2.5 per million population). There is a male predominance (66%) and the median age is 45 years. The bulk of the workforce (128 nephrologists, 92%) is distributed in three of the nine South African provinces, and two provinces have no nephrologist at all. The survey was completed by 57% of the nephrologists. Most reported positive attitudes to their chosen profession; however, 35 nephrologists (43%) reported an excessive workload, 9 (11%) were planning emigration and 15 (19%) were planning early retirement. A higher frequency of dissatisfaction regarding remuneration (39% vs. 15%) and unsatisfactory work conditions (35% vs. 13%) was observed amongst nephrologists working in the public sector compared to the private sector. A total of 13 nephrologists participated in the focus group interviews. The themes which were identified included that of a rewarding profession, an overall shortage of nephrologists, poor career planning, a need for changes to nephrologists' training, excessive workloads with inadequate remuneration, and challenging work environments. CONCLUSION: There are insufficient numbers of nephrologists in South Africa, with a markedly uneven distribution amongst the provinces and healthcare sectors. Qualitative data indicate that South African nephrologists are faced with the challenges of a high workload, obstructive policies and unsatisfactory remuneration. In the public sector, a chronic lack of nephrologist posts and other resources are additional challenges. A substantial proportion of the workforce is contemplating emigration.

Salivary creatinine as a diagnostic tool for evaluating patients with chronic kidney disease.

BACKGROUND: Preliminary studies have shown the potential use of salivary creatinine concentration in the diagnosis of chronic kidney disease (CKD). For saliva to replace serum as a diagnostic tool, studies must be done to determine its effectiveness in the diagnosis and staging of CKD. The aim of the present study was to evaluate the use of salivary creatinine as a safe and non-invasive alternative for identifying patients with CKD. METHODS: A cross-sectional study was conducted at Tygerberg Hospital in Cape Town, on 230 patients, across all stages of CKD. Ethical approval to conduct the study was obtained from the University of the Western Cape Biomedical Research Ethics Committee, and written informed consent was provided by each participant. Saliva and serum samples were collected for creatinine analysis and the correlation determined using Spearman's correlation. Receiver operating characteristics (ROC) analysis was used to determine the diagnostic ability of salivary creatinine. A cut-off value for optimal sensitivity and specificity of salivary creatinine to diagnose CKD with glomerular filtration rate (GFR) < 60 mL/min/1.73 m2 was obtained. RESULTS: Serum creatinine values ranged from 46 µmol/L to 1581 µmol/L, with a median value of 134 µmol/L. Salivary creatinine values ranged from 3 µmol/L to 400 µmol/L, with a median of 11 µmol/L. There was a strong positive correlation (r = 0.82) between serum and salivary creatinine values. Linear regression analysis of serum and salivary creatinine for CKD patients was significant in all CKD stages, except for stage 1. Area under the curve for salivary creatinine was 0.839. A cut-off value of 8.5 µmol/L yielded a sensitivity of 78.3% and specificity of 74.0% for classifying patients as having CKD based on estimated GFR < 60 mL/min/1.73 m2. CONCLUSIONS: The results support the potential of salivary creatinine as a non-invasive diagnostic tool for estimating GFR and identifying patients with CKD.

Hypodipsic-hypernatremia syndrome in an adult with polycythemia: a case report.

BACKGROUND: Hypernatremia is a very common electrolyte disorder and is frequently encountered in out-patient as well as in-hospital settings. We describe an adult who was found to have unexplained relative polycythemia and episodic hypernatremia. A diagnosis of idiopathic hypodipsic-hypernatremia syndrome was made and the patient was managed with a water-drinking schedule. CASE PRESENTATION: A 24-year-old South African-Indian man was found to have polycythemia in association with episodes of hypernatremia. Investigations indicated that he had relative polycythemia. He experienced no thirst at a time when his serum sodium concentration was found to be 151 mmol/L. Further testing indicated that his renal response to arginine vasopressin was intact and magnetic resonance imaging of his brain revealed no hypothalamic lesions. A diagnosis of idiopathic hypodipsic-hypernatremia syndrome was made and he was managed with a water-drinking schedule that corrected his hypernatremia. CONCLUSION: Hypodipsia should always be considered when a patient without physical or cognitive disability presents with unexplained episodic hypernatremia or with relative polycythemia.

Awakening the sleeping kidney in a dialysis-dependent patient with fibromuscular dysplasia: A case report and review of literature.

Renal artery stenosis is a common cause of secondary hypertension and chronic kidney disease. We present here a case of fibromuscular dysplasia that was treated with surgical revascularization, resulting in recovery of kidney function with eventual cessation of chronic dialysis. The case involves a 25-year-old female with coincidentally discovered hypertension, who underwent further investigations revealing a diagnosis of renal artery stenosis due to fibromuscular dysplasia. She subsequently developed two episodes of malignant hypertension, with flash pulmonary oedema and worsening renal failure that resulted in dialysis dependence. After evidence was obtained that the right kidney was still viable, a revascularization procedure was performed, improving blood pressure control and restoring kidney function, thereby allowing dialysis to be stopped. This case highlights the importance of evaluating patients with renal artery stenosis for revascularization before committing them to a life of chronic dialysis.

Effect of improving the usability of an e-learning resource: a randomized trial.

Optimizing the usability of e-learning materials is necessary to reduce extraneous cognitive load and maximize their potential educational impact. However, this is often neglected, especially when time and other resources are limited. We conducted a randomized trial to investigate whether a usability evaluation of our multimedia e-learning resource, followed by fixing of all problems identified, would translate into improvements in usability parameters and learning by medical residents. Two iterations of our e-learning resource [version 1 (V1) and version 2 (V2)] were compared. V1 was the first fully functional version and V2 was the revised version after all identified usability problems were addressed. Residents in internal medicine and anesthesiology were randomly assigned to one of the versions. Usability was evaluated by having participants complete a user satisfaction questionnaire and by recording and analyzing their interactions with the application. The effect on learning was assessed by questions designed to test the retention and transfer of knowledge. Participants reported high levels of satisfaction with both versions, with good ratings on the System Usability Scale and adjective rating scale. In contrast, analysis of video recordings revealed significant differences in the occurrence of serious usability problems between the two versions, in particular in the interactive HandsOn case with its treatment simulation, where there was a median of five serious problem instances (range: 0-50) recorded per participant for V1 and zero instances (range: 0-1) for V2 (P < 0.001). There were no differences in tests of retention or transfer of knowledge between the two versions. In conclusion, usability evaluation followed by a redesign of our e-learning resource resulted in significant improvements in usability. This is likely to translate into improved motivation and willingness to engage with the learning material. In this population of relatively high-knowledge participants, learning scores were similar across the two versions.

Bolus administration of intravenous glucose in the treatment of hyperkalemia: a randomized controlled trial.

BACKGROUND: Hyperkalemia is a common medical emergency that may result in serious cardiac arrhythmias. Standard therapy with insulin plus glucose reliably lowers the serum potassium concentration ([K(+)]) but carries the risk of hypoglycemia. This study examined whether an intravenous glucose-only bolus lowers serum [K(+)] in stable, nondiabetic, hyperkalemic patients and compared this intervention with insulin-plus-glucose therapy. METHODS: A randomized, crossover study was conducted in 10 chronic hemodialysis patients who were prone to hyperkalemia. Administration of 10 units of insulin with 100 ml of 50% glucose (50 g) was compared with the administration of 100 ml of 50% glucose only. Serum [K(+)] was measured up to 60 min. Patients were monitored for hypoglycemia and EKG changes. RESULTS: Baseline serum [K(+)] was 6.01 ± 0.87 and 6.23 ± 1.20 mmol/l in the insulin and glucose-only groups, respectively (p = 0.45). At 60 min, the glucose-only group had a fall in [K(+)] of 0.50 ± 0.31 mmol/l (p < 0.001). In the insulin group, there was a fall of 0.83 ± 0.53 mmol/l at 60 min (p < 0.001) and a lower serum [K(+)] at that time compared to the glucose-only group (5.18 ± 0.76 vs. 5.73 ± 1.12 mmol/l, respectively; p = 0.01). In the glucose-only group, the glucose area under the curve (AUC) was greater and the insulin AUC was smaller. Two patients in the insulin group developed hypoglycemia. CONCLUSION: Infusion of a glucose-only bolus caused a clinically significant decrease in serum [K(+)] without any episodes of hypoglycemia.

An efficient approach to improve the usability of e-learning resources: the role of heuristic evaluation.

Optimizing the usability of e-learning materials is necessary to maximize their potential educational impact, but this is often neglected when time and other resources are limited, leading to the release of materials that cannot deliver the desired learning outcomes. As clinician-teachers in a resource-constrained environment, we investigated whether heuristic evaluation of our multimedia e-learning resource by a panel of experts would be an effective and efficient alternative to testing with end users. We engaged six inspectors, whose expertise included usability, e-learning, instructional design, medical informatics, and the content area of nephrology. They applied a set of commonly used heuristics to identify usability problems, assigning severity scores to each problem. The identification of serious problems was compared with problems previously found by user testing. The panel completed their evaluations within 1 wk and identified a total of 22 distinct usability problems, 11 of which were considered serious. The problems violated the heuristics of visibility of system status, user control and freedom, match with the real world, intuitive visual layout, consistency and conformity to standards, aesthetic and minimalist design, error prevention and tolerance, and help and documentation. Compared with user testing, heuristic evaluation found most, but not all, of the serious problems. Combining heuristic evaluation and user testing, with each involving a small number of participants, may be an effective and efficient way of improving the usability of e-learning materials. Heuristic evaluation should ideally be used first to identify the most obvious problems and, once these are fixed, should be followed by testing with typical end users.

Development and evaluation of a multimedia e-learning resource for electrolyte and acid-base disorders.

This article reports on the development and evaluation of a Web-based application that provides instruction and hands-on practice in managing electrolyte and acid-base disorders. Our teaching approach, which focuses on concepts rather than details, encourages quantitative analysis and a logical problem-solving approach. Identifying any dangers to the patient is a vital first step. Concepts such as an "appropriate response" to a given perturbation and the need for electroneutrality in body fluids are used repeatedly. Our Electrolyte Workshop was developed using Flash and followed an iterative design process. Two case-based tutorials were built in this first phase, with one tutorial including an interactive treatment simulation. Users select from a menu of therapies and see the impact of their choices on the patient. Appropriate text messages are displayed, and changes in body compartment sizes, brain size, and plasma sodium concentrations are illustrated via Flash animation. Challenges encountered included a shortage of skilled Flash developers, budgetary constraints, and challenges in communication between the authors and the developers. The application was evaluated via user testing by residents and specialists in internal medicine. Satisfaction was measured with a questionnaire based on the System Usability Scale. The mean System Usability Scale score was 78.4 ± 13.8, indicating a good level of usability. Participants rated the content as being scientifically sound; they liked the teaching approach and felt that concepts were conveyed clearly. They indicated that the application held their interest, that it increased their understanding of hyponatremia, and that they would recommend this learning resource to others.