A practical approach to implementing incremental haemodialysis.

The majority of end-stage kidney disease patients are treated with haemodialysis (HD). Starting HD can pose physical, social, and psychological challenges to patients, and mortality rates within the first 6 months are disproportionately high, with intensive HD regimens implicated as a potential factor. Starting HD with an incremental approach, taking residual kidney function (RKF) into account, potentially allows for a gentle start with reduced dialysis intensity. Dialysis intensity (session time or frequency) can then be proportionally increased as RKF reduces. This approach to starting HD has been reported in observational studies to result in better patient self-reported health quality of life and reduced costs, and now several definitive randomised controlled trials are underway comparing an incremental approach to the conventional thrice weekly paradigm. Physician concerns over the risk of inadequate dialysis, with consequent increased emergency admissions, and practical challenges of how to estimate RKF and implement incremental dialysis have impeded widespread adoption. Addressing these challenges is paramount to increasing the uptake of incremental HD. Careful patient selection lies at the heart of a successful incremental HD programme. Generally, patients with a residual urea clearance of > 3 ml/min/1.73 m2 can be considered suitable for starting with incremental HD provided they comply with fluid intake, salt and other dietary recommendations. Calculating RKF from regular interdialytic urine collections and appropriately adjusting sessional HD clearance targets are practical and conceptual challenges. In this report we aim to disentangle these complexities and provide a step-by-step guide for patient selection and adjusting dialysis sessional targets.

Participatory co-design and normalisation process theory with staff and patients to implement digital ways of working into routine care: the example of electronic patient-reported outcomes in UK renal services.

BACKGROUND: Successful implementation of digital health systems requires contextually sensitive solutions. Working directly with system users and drawing on implementation science frameworks are both recommended. We sought to combine Normalisation Process Theory (NPT) with participatory co-design methods, to work with healthcare stakeholders to generate implementation support recommendations for a new electronic patient reported outcome measure (ePRO) in renal services. ePROs collect data on patient-reported symptom burden and illness experience overtime, requiring sustained engagement and integration into existing systems. METHODS: We identified co-design methods that could be mapped to NPT constructs to generate relevant qualitative data. Patients and staff from three renal units in England participated in empathy and process mapping activities to understand 'coherence' (why the ePRO should be completed) and 'cognitive participation' (who would be involved in collecting the ePRO). Observation of routine unit activity was completed to understand 'collective action' (how the collection of ePRO could integrate with service routines). RESULTS: The mapping activities and observation enabled the research team to become more aware of the key needs of both staff and patients. Working within sites enabled us to consider local resources and barriers. This produced 'core and custom' recommendations specifying core needs that could be met with customised local solutions. We identified two over-arching themes which need to be considered when introducing new digital systems (1) That data collection is physical (electronic systems need to fit into physical spaces and routines), and (2) That data collection is intentional (system users must be convinced of the value of collecting the data). CONCLUSIONS: We demonstrate that NPT constructs can be operationalised through participatory co-design to work with stakeholders and within settings to collaboratively produce implementation support recommendations. This enables production of contextually sensitive implementation recommendations, informed by qualitative evidence, theory, and stakeholder input. Further longitudinal evaluation is necessary to determine how successful the recommendations are in practice.

Allopurinol as a therapeutic option in cardiovascular disease.

Epidemiological studies indicate that hyperuricaemia is an independent risk factor for cardiovascular disease. Alongside uric acid formation, increased xanthine oxidase activity also results in the formation of oxidative free radicals and superoxide particles. Oxidative stress significantly contributes to the development of cardiovascular disease, including endothelial cell dysfunction, atherosclerosis, vascular calcification and impaired myocardial energetics. Allopurinol, a competitive xanthine oxidase inhibitor, in addition to reducing serum uric acid levels, can act as a free radical scavenger. Although traditionally used for the management of gout, there has been renewed interest in the role of allopurinol in the management of cardiovascular disease. In this review, we summarise the role of the xanthine oxidase pathway in the generation of oxidative stress and evaluate the current body of evidence assessing the clinical effects of allopurinol in patients with cardiovascular disease. A number of small clinical studies have shown a beneficial effect of allopurinol in reducing ischemia-reperfusion injury in the setting of bypass surgery and coronary angioplasty. Additionally, studies in heart failure indicate a potential favourable effect of allopurinol on endothelial dysfunction, LV function and haemodynamic indices, particularly in those with raised serum uric acid levels. Whilst this cheap and readily available pharmacological option may offer a very cost effective therapeutic option, large-scale prospective studies are required to better delineate its role in reducing hard clinical end-points.

Comparison of resting and total energy expenditure in peritoneal dialysis patients and body composition measured by dual-energy X-ray absorptiometry.

Under basal resting conditions muscle metabolism is reduced, whereas metabolism increases with physical activity. We wished to determine whether there was an association between resting energy expenditure (REE) and total energy expenditure (TEE) in peritoneal dialysis (PD) patients and lean body mass (LBM). We determined REE and TEE by recently validated equations, using doubly labelled isotopic water, and LBM by dual-energy X-ray absorptiometry (DXA) scanning. We studied 87 patients, 50 male (57.4%), 25 diabetic (28.7%), mean age 60.3±17.6 years, with a median PD treatment of 11.4 (4.7-29.5) months. The mean weight was 70.1±17.7 kg with a REE of 1509±245 kcal/day and TEE 1947±378 kcal/day. REE was associated with body size (weight r=0.78 and body mass index (BMI) r=0.72) and body composition (LBM r=0.77, lean body mass index (LBMI) r=0.76, r=0.62), all P<0.001). For TEE, there was an association with weight r=0.58, BMI r=0.49 and body composition (LBM r=0.64, LBMI (r=0.54), all P<0.001). We compared LBMI measured by DXA and that estimated by the Boer equation using anthropomorphic measurements, which overestimated and underestimated LBM for smaller patients and heavier patients, respectively. Muscle metabolism is reduced at rest and increases with physical activity. Whereas previous reports based on REE did not show any association with LBM, we found an association between both REE and TEE, using a recently validated equation derived from dialysis patients, and LBM measured by DXA scanning. Estimation of muscle mass from anthropomorphic measurements systematically overestimated LBM for small patients and conversely underestimated for heavier patients.

Comparison of energy estimates in chronic kidney disease using doubly-labelled water.

BACKGROUND: Total energy expenditure (TEE) is estimated in clinical practice as a combined measure of resting energy expenditure and physical activity level. Commonly available questionnaires to estimate physical activity level have not been validated in patients with kidney disease using the doubly-labelled water method. METHODS: This prospective, cross-sectional study was conducted on 40 patients with chronic kidney disease stages 1-5 with the objective of validating two physical activity questionnaires: the Recent Physical Activity Questionnaire (RPAQ) and the Stanford 7-day recall questionnaire. TEE was measured using doubly-labelled water technique. TEE was also estimated using predicted resting energy expenditure and estimated physical activity measures from the questionnaires. RESULTS: Measured TEE correlated better with TEE estimated from RPAQ compared to that from the Stanford questionnaire. In Bland-Altman analysis, TEE estimated from RPAQ had the least bias and narrower limits of agreement compared to the measured TEE. A metabolic equivalent of task value of 1.3 for the unaccounted time in RPAQ provided the best approximation of estimated TEE to the measured TEE. CONCLUSIONS: RPAQ is an acceptable questionnaire tool for assessing physical activity level in patients with chronic kidney disease.

Management of acute renal failure.

Acute renal failure is a common condition, frequently encountered in both community practice and hospital inpatients. While it remains a heterologous condition, following basic principles makes investigation straightforward, and initial management follows a standard pathway in most patients. This article shows this, advises on therapeutic strategies, including those in special situations, and should help the clinician in deciding when to refer to a nephrologist, and when to consider renal replacement therapy.

Polymyalgia rheumatica preceding small-vessel vasculitis: changed spots or misdiagnosis?

BACKGROUND: Systemic small-vessel vasculitis (SVV) is increasing in incidence and age of diagnosis. Presenting features may mimic those of polymyalgia rheumatica (PMR), a common disease of the elderly. AIM: To test the hypotheses that SVV is frequently misdiagnosed as PMR in elderly patients, that this results in a delay in diagnosis and appropriate treatment, and that the natural history and clinical features are different. DESIGN: Retrospective case-control study. METHODS: Cases of glomerulonephritis due to SVV at a single centre over a 12-year period were analysed, comparing those treated previously for PMR (PMR(+)) to the remainder of the cohort (PMR(-)). RESULTS: Of 86 patients with complete follow-up, 13% had been treated previously for PMR. PMR(+) patients had a longer duration of symptoms prior to SVV diagnosis (396 vs. 107 days, p = 0.001) and were less likely to be dialysis-dependent at diagnosis (36% vs. 68%, p < 0.05). Despite the delay in diagnosis, there was a trend towards lower serum creatinine (392 vs. 591 micro M), lower relapse rate (0.04 versus 0.15 episodes/patient-year) and lower incidence of death/end-stage renal failure (27% vs. 53%) in the PMR(+) group. DISCUSSION: SVV is frequently misdiagnosed as PMR, especially in those patients with indolent disease, although this did not appear to adversely affect outcome. We recommend that all patients suspected of suffering from PMR undergo careful urinalysis to look for haematuria or proteinuria, and that a low threshold for ANCA testing is maintained.

Wegener's granulomatosis presenting as acute suppurative interstitial nephritis.

A 78 year old man presented with acute renal failure following a prolonged respiratory illness. A renal biopsy demonstrated severe suppurative interstitial nephritis with normal glomeruli. After nine weeks of antibiotics he remained anuric and a second biopsy demonstrated pauci-immune, necrotising glomerulonephritis. His subsequent clinical course was consistent with a diagnosis of Wegener's granulomatosis and antineutrophil cytoplasmic antibodies (ANCA) were detected. This is the first reported case of Wegener's granulomatosis presenting with an isolated tubulointerstitial lesion.

Reversal of steal syndrome following creation of arteriovenous fistula by banding with a Gore-Tex cuff: a new technique.

Steal syndrome, especially in elderly patients with peripheral vascular disease, is a serious complication following creation of an arteriovenous fistula (AVF) that, if neglected, can lead to amputation. The classic maneuver to deal with the steal syndrome is the ligation of the AVF and performance of another procedure to gain dialysis access. We describe a simple technique of effectively reversing the steal syndrome by banding the vein of the AVF with a ringed Gore-Tex cuff that salvages the AVF and allows its immediate use for dialysis.

What is hypertension in chronic haemodialysis? The role of interdialytic blood pressure monitoring.

BACKGROUND: Hypertension in chronic haemodialysis patients contributes significantly to morbidity and mortality. Treatment decisions are usually based on predialysis readings, which may not accurately reflect control during the interdialytic period. METHODS: We studied 40 randomly selected subjects on haemodialysis and compared readings by different methods at set times during the dialysis session with the 48-h interdialytic ambulatory readings. Conventional sphygmomanometer, automated Dinamap and Tm 2421(A&D) ambulatory monitor were used for BP measurements. RESULTS: Conventional sphygmomanometry and self measured automatic readings (Dinamap) were highly correlated (systolic r=0.93, P<0.001; diastolic r=0.90, P<0.001). Mean blood pressure on arrival ((PreC(0)) 158 mmHg systolic, 80 mmHg diastolic and 106 mmHg mean) significantly overestimated the mean ambulatory reading during the 6 h prior to attendance ((preAm(6h)) systolic 147 (P<0.01), diastolic 75 (P<0.01), mean 99 (P<0.01)). Fifteen patients (41%) demonstrated a marked difference (>20/10 mmHg) between the PreC(0) and preAm(6h) (white-coat effect) persisting in seven patients (19%) after a period of rest 10 min predialysis (preC(10)) and present even in self-recorded Dinamap readings. There was a significant negative relationship between the systolic rise and the number of months on dialysis (P<0.05). Mean ambulatory BP on interdialytic day 2 was significantly greater than on day 1 whereas the awake-sleep differences were less on day 2 than day 1, both perhaps reflecting differences in volume status. The 20 min post-dialysis measurement (PoC(20)) for systolic, diastolic, and mean, unlike predialysis (PreC(0) and preC(10)), onset (onC) and end of dialysis readings (enC) did not differ significantly from 48 h interdialytic means. CONCLUSIONS: The best representation of interdialytic pressure was the 20-min post-dialysis reading. Walk-in predialysis pressures overestimate mean interdialytic pressures due to a high incidence of white-coat effect, which shows some habituation with time on dialysis. Ambulatory monitoring has a role in evaluating persistent poor blood pressure control in haemodialysis patients.

The effect of exercise during haemodialysis on solute removal.

BACKGROUND: Urea rebound results as urea re-equilibrates between intracellular and intravascular compartments post haemodialysis. The mechanism of the rebound is thought to be due to either a reduced diffusion rate or blood flow. It is hypothesized that low blood flow in the skeletal muscles might be responsible. We tested this by studying the effect of exercise during dialysis on the removal of urea, creatinine and potassium. METHODS: Eleven patients (aged 32-78 years) on haemodialysis (4-58 months) were studied on paired dialysis sessions; one with exercise and the other as a control. Patients pedalled on a cycle for 5-20 min at submaximal workload followed by 10 min rest to achieve a total of 60 min exercise. Plasma concentrations of urea, creatinine and potassium were measured pre-, post- and 30-min post dialysis. The post-dialysis rebound (% rebound) and reduction ratios (RR) of the solutes and equilibrated (two-pool) urea Kt/V were calculated for comparison. RESULTS: The rebound of all three solutes was reduced significantly following exercise. The rebound of urea decreased from 12.4 to 10.9% (median, P<0.01 Wilcoxon signed rank test), creatinine from 21.2 to 17.2% (P<0.001) and potassium from 62 to 44% (P<0.05). Kt/V and RR increased significantly as a result: Kt/V urea from 1.00 to 1.15 (P=0.001), RR urea from 0.63 to 0.68 (P<0.001); Kt/V creatinine from 0.71 to 0.84 (P<0.01); and RR creatinine from 0.51 to 0.57 (P<0.05). CONCLUSION: Exercise increased the efficiency of dialysis by reducing the rebound of solutes due to increased perfusion of the skeletal muscles.