Potassium balances in maintenance hemodialysis

Association between annual variability of potassium levels and prognosis in patients undergoing hemodialysis

BACKGROUND

Hyperkalemia and hypokalemia are associated with mortality in patients undergoing hemodialysis. However, there are few reports on the association between potassium level fluctuations and mortality. We retrospectively investigated the association between serum potassium level variability and mortality in patients undergoing hemodialysis.

METHODS

This study was conducted at a single center. Variability in serum potassium levels was evaluated using the standard deviation of potassium level from July 2011 to June 2012, and its association with prognosis was examined by following up the patients for 5 years. Serum potassium variability was assessed as the coefficient of variation, and the statistical analysis was performed after log transformation.

RESULTS

Among 302 patients (mean age 64.9 ± 13.3; 57.9% male; and median dialysis vintage 70.5 months [interquartile range, IQR 34-138.3]), 135 died during the observation period (median observation period 5.0 years [2.3-5.0]). Although the mean potassium level was not associated with prognosis, serum potassium level variability was associated with prognosis, even after adjustments for confounding factors such as age and dialysis time (hazard ratio: 6.93, 95% confidence interval [Cl] 1.98-25.00, p = 0.001). After the adjustments, the coefficient of variation of potassium level in the highest tertile (T3) showed a higher relative risk for prognosis than that in T1 (relative risk: 1.98, 95% CI 1.19-3.29, p = 0.01).

CONCLUSIONS

Variability in serum potassium levels was associated with mortality in patients undergoing hemodialysis. Careful monitoring of potassium levels and their fluctuations is necessary for this patient population.

Association of Hyperkalemia and Hypokalemia with Patient Characteristics and Clinical Outcomes in Japanese Hemodialysis (HD) Patients

This study aimed to examine the characteristics and clinical outcomes of Japanese hemodialysis patients with dyskalemia. A retrospective study was conducted using a large Japanese hospital group database. Outpatients undergoing thrice-a-week maintenance hemodialysis were stratified into hyperkalemia, hypokalemia, and normokalemia groups based on their pre-dialysis serum potassium (sK) levels during the three-month baseline period. Baseline characteristics of the three groups were described and compared for the following outcomes during follow-up: all-cause mortality, all-cause hospitalization, major adverse cardiovascular events (MACE), cardiac arrest, fatal arrythmia, and death related to arrhythmia. The study included 2846 eligible patients, of which 67% were men with a mean age of 65.65 (SD: 12.63) years. When compared with the normokalemia group (n = 1624, 57.06%), patients in the hypokalemia group (n = 313, 11.00%) were older and suffered from malnutrition, whereas patients in the hyperkalemia group (n = 909, 31.94%) had longer dialysis vintage. The hazard ratios for all-cause mortality and MACE in the hypokalemia group were 1.47 (95% confidence interval [CI], 1.13–1.92) and 1.48 (95% CI, 1.17–1.86), respectively, whereas that of death related to arrhythmia in the hyperkalemia group was 3.11 (95% CI, 1.03–9.33). Thus, dyskalemia in maintenance hemodialysis patients was associated with adverse outcomes, suggesting the importance of optimized sK levels.

A comparison of the mineral element content of 70 different varieties of pear fruit (Pyrus ussuriensis) in China

Background

Pyrus ussuriensis (Maxim.) is a unique pear tree that grows in northern China. The tree has strong cold resistance and can withstand low temperatures from -30 °C to -35 °C. Due to its unique growth environment, its fruit is rich in minerals and has much higher levels of minerals such as K, Ca and Mg than the fruit of Pyrus pyrifolia (Nakai.) and Pyrus bretschneideri (Rehd.) on the market, and many say the ripe fruit tastes better than other varieties. A comprehensive analysis of the characteristics of mineral elements in the fruits of different varieties of P. ussuriensis will provide a valuable scientific basis for the selection, breeding and production of consumer varieties of P. ussuriensis, and provide a more complete understanding of nutritional differences between fruit varieties.

Methods

In this study, 70 varieties of wild, domesticated and cultivated species of P. ussuriensis from different geographical locations were compared. Targeting four main mineral elements and eight trace mineral elements contained in the fruit, the differences in mineral content in the peel and pulp of different varieties of P. ussuriensis were analyzed, compared and classified using modern microwave digestion ICP-MS.

Results

The mineral elements in the fruit of P. ussuriensis generally followed the following content pattern: K > P > Ca > Mg > Na > Al > Fe > Zn > Cu > Cr > Pb > Cd. The mineral element compositions in the peel and pulp of different fruits were also significantly different. The four main mineral elements in the peel were K > Ca > P > Mg, and K > P > Mg > Ca in the pulp. The mineral element content of wild fruit varieties was higher than that of cultivated and domesticated varieties. Correlation analysis results showed that there was a significant positive correlation between K, P and Cu in both the peel and pulp of P. ussuriensis fruit (P < 0. 01). Cluster analysis results showed that the 70 varieties of P. ussuriensis could be divided into three slightly different categories according to the content of the peel or pulp. According to the contents of the fruit peel, these varieties were divided into: (1) varieties with high Na, Mg, P, K, Fe and Zn content, (2) varieties with high Ca content and (3) varieties with medium levels of mineral elements. According to the fruit pulp content, these varieties were divided into: (1) varieties with high Mg, P and K content, (2) varieties with low mineral element content, and (3) varieties with high Na and Ca content. The comprehensive analysis of relevant mineral element content factors showed that 'SSHMSL,' 'QYL,' 'SWSL' and 'ZLTSL-3' were the best varieties, and could be used as the focus varieties of future breeding programs for large-scale pear production.

Serum Potassium and Mortality Risk in Hemodialysis Patients: A Cohort Study

Rationale & Objective

Both hypo- and hyperkalemia can cause fatal cardiac arrhythmias. Although predialysis serum potassium level is a known modifiable risk factor for death in patients receiving hemodialysis, especially for hypokalemia, this risk may be underestimated. Therefore, we investigated the relationship between predialysis serum potassium level and death in incident hemodialysis patients and whether there is an optimum level.

Study Design

Prospective multicenter cohort study.

Setting & Participants

1,117 incident hemodialysis patients (aged >18 years) from the Netherlands Cooperative Study on the Adequacy of Dialysis-2 study were included and followed from their first hemodialysis treatment until death, transplantation, switch to peritoneal dialysis, or a maximum of 10 years.

Exposure

Predialysis serum potassium levels were obtained every 6 months and divided into 6 categories: ≤4.0 mmol/L, >4.0 mmol/L to ≤4.5 mmol/L, >4.5 mmol/L to ≤5.0 mmol/L, >5.0 mmol/L to ≤5.5 mmol/L (reference), >5.5 mmol/L to ≤6.0 mmol/L, and >6.0 mmol/L.

Outcomes

6-month all-cause mortality.

Analytical Approach

Cox proportional hazards and restricted cubic spline analyses with time-dependent predialysis serum potassium levels were used to calculate the adjusted HRs for death.

Results

At baseline, the mean age of the patients was 63 years (standard deviation, 14 years), 58% were men, 26% smoked, 24% had diabetes, 32% had cardiovascular disease, the mean serum potassium level was 5.0 mmol/L (standard deviation, 0.8 mmol/L), 7% had a low subjective global assessment score, and the median residual kidney function was 3.5 mL/min/1.73 m² (IQR, 1.4-4.8 mL/min/1.73 m²). During the 10-year follow-up, 555 (50%) deaths were observed. Multivariable adjusted HRs for death according to the 6 potassium categories were as follows: 1.42 (95% CI, 1.01-1.99), 1.09 (95% CI, 0.82-1.45), 1.21 (95% CI, 0.94-1.56), 1 (reference), 0.95 (95% CI, 0.71-1.28), and 1.32 (95% CI, 0.97-1.81).

Limitations

Shorter intervals between potassium measurements would have allowed for more precise mortality risk estimations.

Conclusions

We found a U-shaped relationship between serum potassium level and death in incident hemodialysis patients. A low predialysis serum potassium level was associated with a 1.4-fold stronger risk of death than the optimal level of approximately 5.1 mmol/L. These results may imply the cautious use of potassium-lowering therapy and a potassium-restricted diet in patients receiving hemodialysis.

Intraoperative Renal Replacement Therapy: Practical Information for Anesthesiologists

Previous publications regarding perioperative renal replacement therapy (RRT) have focused on the general care of the RRT-dependent patient and provided a broad overview of the various RRT modalities. The goal of this review article is to provide anesthesiologists with specific practical information regarding the possible intraoperative advantages and limitations of each modality, mandatory equipment to institute intraoperative therapy, and background knowledge necessary to communicate effectively with nephrologists and/or support staff regarding the intraoperative RRT goals.

Hyperkalemia excursions are associated with an increased risk of mortality and hospitalizations in hemodialysis patients

BACKGROUND

Hyperkalemia is common among hemodialysis (HD) patients and has been associated with adverse clinical outcomes. Previous studies considered a single serum potassium (K) measurement or time-averaged values, but serum K excursions out of the target range may be more reflective of true hyperkalemia events. We assessed whether hyperkalemia excursions lead to an elevated risk of adverse clinical outcomes.

METHODS

Using data from 21 countries in Phases 4-6 (2009-18) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), we investigated the associations between peak serum K level, measured monthly predialysis, over a 4-month period ('peak K') and clinical outcomes over the subsequent 4 months using Cox regression, adjusted for potential confounders.

RESULTS

The analysis included 62 070 patients contributing a median of 3 (interquartile range 2-6) 4-month periods. The prevalence of hyperkalemia based on peak K was 58% for >5.0, 30% for >5.5 and 12% for >6.0 mEq/L. The all-cause mortality hazard ratio for peak K (reference ≤5.0 mEq/L) was 1.15 [95% confidence interval (CI) 1.09, 1.21] for 5.1-5.5 mEq/L, 1.19 (1.12, 1.26) for 5.6-6.0 mEq/L and 1.33 (1.23, 1.43) for >6.0 mEq/L. Results were qualitatively consistent when analyzing hospitalizations and a cardiovascular composite outcome.

CONCLUSIONS

Among HD patients, we identified a lower K threshold (peak K 5.1-5.5 mEq/L) than previously reported for increased risk of hospitalization and mortality, with the implication that a greater proportion (>50%) of the HD population may be at risk. A reassessment of hyperkalemia severity ranges is needed, as well as an exploration of new strategies for effective management of chronic hyperkalemia.

Dyselectrolytemia-management and implications in hemodialysis (Review)

Hemodialysis is a method for the renal replacement therapy followed by series of acute and chronic complications. Dyselectrolytemia appears in patients undergoing dialysis through mechanisms related to the chronic kidney disease and/or to the dialysis therapy and for this group of patients it is associated with an increase of morbidity and mortality. The dialysate has a standard composition, which can be modified according to the patient's characteristics. During hemodialysis patients are exposed to 18,000-36.000 litres of water/year, and the water purity along with the biochemical composition of the dialysate are essential. The individualization of the dialysis prescription is recommended for each patient and it has an important role in preventing the occurrence of dyselectrolyemia. The individualization of the treatment prescription according to the blood constants of each patient is the prerogative of the nephrologist and the association of the electrolyte imbalances with the patients cardiovascular mortality explains the importance of paying special attention to them.

New Treatment Options for Hyperkalemia in Patients with Chronic Kidney Disease

Hyperkalemia may cause life-threatening cardiac and neuromuscular alterations, and it is associated with high mortality rates. Its treatment includes a multifaceted approach, guided by potassium levels and clinical presentation. In general, treatment of hyperkalemia may be directed towards stabilizing cell membrane potential, promoting transcellular potassium shift and lowering total K+ body content. The latter can be obtained by dialysis, or by increasing potassium elimination by urine or the gastrointestinal tract. Until recently, the only therapeutic option for increasing fecal K+ excretion was represented by the cation-exchanging resin sodium polystyrene sulfonate. However, despite its common use, the efficacy of this drug has been poorly studied in controlled studies, and concerns about its safety have been reported. Interestingly, new drugs, namely patiromer and sodium zirconium cyclosilicate, have been developed to treat hyperkalemia by increasing gastrointestinal potassium elimination. These medications have proved their efficacy and safety in large clinical trials, involving subjects at high risk of hyperkalemia, such as patients with heart failure and chronic kidney disease. In this review, we discuss the mechanisms of action and the updated data of patiromer and sodium zirconium cyclosilicate, considering that the availability of these new treatment options offers the possibility of improving the management of both acute and chronic hyperkalemia.

Continuous renal replacement therapy in the treatment of severe hyperkalemia: An in vitro study

Introduction:

Continuous renal replacement therapy is not presently recommended in the treatment of life-threatening hyperkalemia. There are no specific recommendations in hemodialysis to treat hyperkalemia. We hypothesized an in vitro model may provide valuable information on the usefulness of continuous renal replacement therapy to treat severe hyperkalemia.

Methods:

A potassium-free solute was used instead of diluted blood for continuous renal replacement therapy with a simulated blood flowrate set at 200 mL/min. The mode of elimination included continuous filtration, continuous dialysis, and continuous diafiltration using a flowrate of 4000 mL/min for continuous filtration and continuous dialysis modes, and a ratio of 2500/1500 in the continuous diafiltration mode.

Results:

The mean initial potassium in the central compartment was 10.1 ± 0.4 mmol/L. The clearances in the continuous diafiltration, continuous filtration, and continuous dialysis were 3.4 ± 0.5, 3.6 ± 0.1, and 3.7 ± 0.1 L/h, respectively, not significantly different. Continuous dialysis resulted in the lowest workload for staff. Increasing the continuous dialysis flowrates from 2000 to 8000 mL/h increased clearance from 2.3 ± 0.3 to 6.2 ± 0.8 L/h. The delays in decreasing the potassium concentration to 5.5 mmol/L dropped from 120 to 45 min, respectively. Potassium eliminated in the first hour increased from 18 to 38 mmol that compared favorably with hemodialysis. Decrease in simulated blood flowrate from 200 to 50 mL/min moderately but significantly decreased the clearance from 3.7 to 3.0 L/h.

Conclusion:

Hyperkalemia is efficiently treated by continuous renal replacement therapy using the dialysis mode. Caution is needed to prevent the onset of severe hypokalemia within 40 min after initiation of the session.

Microfluidic DNA-based potassium nanosensors for improved dialysis treatment

BACKGROUND

Patients with end-stage renal disease (ESRD) have failed kidney function, and often must be treated with hemodialysis to extend the patient's life by artificially removing excess fluid and toxins from the blood. However, life-threatening treatment complications can occur because hemodialysis protocols are adjusted infrequently, as opposed to the kidneys which filter blood continuously. Infrequent blood tests, about once per month on average, are used to adjust hemodialysis protocols and as a result, patients can experience electrolyte imbalances, which can contribute to premature patient deaths from treatment complications, such as sudden cardiac death. Since hemodialysis can lead to blood loss, drawing additional blood for tests to assess the patient's kidney function and blood markers is limited. However, sampling multiple drops of blood per session using a microfluidic device has the potential to reduce not only the amount of blood drawn and avoid unnecessary venipuncture, but also reduce costs by limiting medical complications of hemodialysis and provide a more comprehensive assessment of the patient's health status in real time.

RESULT

We present preliminary proof-of-concept results of a microfluidic device which uses DNA-based fluorescence nanosensors to measure potassium concentration in a flowing solution. In a matter of minutes, the flowing potassium solution reduced the fluorescence intensity of the nanosensors to a steady-state value.

CONCLUSIONS

These proof-of-concept results demonstrate the ability of our DNA-based nanosensors to measure potassium concentration in a microfluidic device. The long-term goal is to integrate this technology with a device to measure potassium and eventually other blood contents multiple times throughout a hemodialysis session, enabling protocol adjustment similar to a healthy kidney.

Safety evaluation and cardiovascular effect of additional use of spironolactone in hemodialysis patients: a meta-analysis

Objective: To evaluate the safety and cardiovascular effect of low-dose spironolactone administration in end-stage renal failure patients undergoing hemodialysis coupled with conventional treatment.

Methods: We conducted a systematic search for clinical trials on the safety and cardiovascular effect of additional low-dose spironolactone in hemodialysis patients. The search was performed on PubMed, EMBASE, Cochrane Library, and CBM databases. Relevant references (up to February 2016) were retrieved and subsequent results analyzed with a random-effects model or a fixed-effects model.

Results: We identified nine trials with a total sample size of 765 patients. The results did not indicate significant differences regarding safety and serum potassium levels (mean difference [MD]=0.23, P=0.09) between the two treatment options. However, patients receiving low-dose spironolactone exhibited improvements in left venticular mass index (LVMI) (standardized mean difference= –0.58, P<0.00001) and left ventricular ejection fraction (LVEF) (MD=4.91, P<0.0001) with an additional decrease in systolic blood pressure (MD= –6.97, P=0.0001) and diastolic blood pressure (MD= –4.01, P=0.007). Furthermore, the clinical (OR=0.4, P=0.0003) or cardiovascular and cerebrovascular-related (OR=0.4, P=0.002) mortality was significantly lower among those patients.

Conclusion: These results indicated that additional use of low-dose spironolactone associated with conventional treatment does not have a significant impact on serum potassium levels in hemodialysis patients. What’s more, it might exert a protective effect on the cardiovascular system by optimizing LVMI, improving LVEF, decreasing arterial blood pressure and reducing events-related mortality. Further large sample size studies are needed to support these findings.

Production of Low-Potassium Content Melon Through Hydroponic Nutrient Management Using Perlite Substrate

Chronic kidney disease patients are restricted to foods with high potassium content but our daily diets including melon are rich in potassium. Therefore, we investigated the production of low-potassium melon through hydroponic nutrient management in soilless culture using perlite substrate during autumn season of 2012, 2014 and spring season of 2016. In the first study, melon plants were supplied with 50% standard 'Enshi' nutrient solution until first 2 weeks of culture. In 3rd and 4th week, amount of applied potassium was 50, 75, 100, and 125% of required potassium nitrate for each plant per week (based on our previous study). It was found that, melon plants grown with 50% of its required potassium nitrate produced fruits with about 53% low-potassium compared to control. In the following study, four cultivars viz. Panna, Miyabi shunjuukei, Miyabi akifuyu412, and Miyabi soushun banshun309 were evaluated for their relative suitability of low-potassium melon production. Results showed insignificant difference in fruit potassium content among the cultivars used. Source of potassium fertilizer as potassium nitrate and potassium sulfate and their restriction (from 1 or 2 weeks after anthesis) were also studied. There were no influences on fruit potassium content and yield due to sources of potassium fertilizer and restriction timings. In our previous studies, it was evident that potassium can be translocated from leaves to fruits at maturity when it was supplied nutrient without potassium. Thus, we also studied total number of leaves per plant (23, 24, 25, 26, and 27 leaves per plant). It was evident that fruit potassium, yield, and quality were not influenced significantly due to differences in number of leaves per plant. These studies showed that restriction of potassium nitrate in the culture solution from anthesis to harvest could produce melon fruits with low-potassium (>20%) content compared to potassium content of greenhouse grown melon (340 mg/100 g FW). Quality testing and clinical validation of low-potassium melon also showed positive responses compared to greenhouse grown melon.

Microgreens Production with Low Potassium Content for Patients with Impaired Kidney Function

Chronic kidney disease represents a global problem together with other so-called 'lifestyle-related diseases'. Unlike the healthy population, for the patients with impaired kidney function, it is of course prudent to recommend a restriction of high-potassium foods. Thus, it is suggested to limit the consumption of vegetables, because they generally contain high concentrations of potassium. At the same time, a lower consumption of vegetables reduces the intake of healthy compounds such as vitamins, fibers, and antioxidants, which also reduces the vegetables' potential benefit in chronic kidney disease patients. Microgreens are an emerging class of specialty crop that represent a nutritious and refined food. In this study, for the first time, some chicory (local variety 'Molfetta' and cultivar 'Italico a costa rossa') and lettuce (cultivar 'Bionda da taglio') genotypes were grown using a hydroponic system with different potassium (K) levels (0, 29.1, 58.4, and 117 mg L-1) in order to produce microgreens with a low potassium content. The crop performances, cations content, proximate composition, and antioxidant activity were analyzed. Independent of the genotype, the K content in the microgreens was successfully reduced using a nutrient solution (NS), without K or with 29.1 mg K L-1, which supplied between 103 and 129 mg of K 100 g-1 FW (about 7.7⁻8.6% of the K daily intake that was recommended for the patients that were affected by chronic kidney disease). Whereas, 100 g of microgreens that were grown by using an NS with 58.4 or 117 mg K L-1 supply between 225 and 250 mg of K (about 15.8⁻16.5% of the K daily intake recommended for patients affected by chronic kidney disease). No differences were observed in terms of the shoot height, dry matter, proximate composition, and visual quality. A slightly lower yield was observed using an NS with a K concentration.

The Impact of Hemodialysis Frequency and Duration on Blood Pressure Management and Quality of Life in End-Stage Renal Disease Patients

Cardiovascular complications are the most prominent causes of morbidity and mortality among chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients undergoing standard hemodialysis (HD) therapy. Cardiovascular disease risk is increased significantly through persistent hypertension and blood pressure (BP) fluctuation, which are the most common complications of CKD. It was hypothesized that an extended approach with lengthier and more frequent dialysis sessions, referred to in this paper as "extended hemodialysis" (EHD), can potentially lower and stabilize blood pressure, and consequently reduce the rate of morbidity and mortality. A greater reduction of volume (salt and water) with higher frequency can improve patient quality of life (QOL). Eleven papers, including clinical trials and systematic reviews were chosen and analyzed. The extracted data was used to evaluate the change in blood pressure levels between standard HD and EHD. Overall, the studies showed that EHD resulted in improved blood pressure management; therefore, we concluded that there will be a decrease in cardiovascular disease risk, stroke, and morbidity and mortality rate. There will be also an improvement in patient QOL due to beneficial effects of the EHD.

Changes in Body Water Caused by Sleep Deprivation in Taeeum and Soyang Types in Sasang Medicine: Prospective Intervention Study

Background

There is a negative relationship between sleep deprivation and health. However, no study has investigated the effect of sleep deprivation on individuals with different body composition. The aim of this study was to determine the differential effect of sleep deprivation in individuals with different body compositions (fluid) according to Soyang type (SY) and Taeeum type (TE).

Methods

Sixty-two cognitively normal, middle-aged people with normal sleep patterns were recruited from the local population. The duration of participants' sleep was restricted to 4 h/day during the intervention phase. To examine the physiological changes brought on by sleep deprivation and recovery, 10 ml of venous blood was obtained.

Results

Total Body Water (TBW) and Extracellular Water (ECW) were significantly different between the groups in the intervention phase. Physiological parameters also varied from the beginning of the resting phase to the end of the experiment. Potassium levels changed more in SY than TE individuals.

Conclusion

Participants responded differently to the same amount of sleep deprivation depending on their Sasang constitution types. This study indicated that SY individuals were more sensitive to sleep deprivation and were slower to recover from the effects of sleep deprivation than TE individuals.

We Use Dialysate Potassium Levels That Are Too Low in Hemodialysis

Sudden cardiac death accounts for a quarter of all deaths in hemodialysis patients. While this group is at high risk for cardiovascular events, there are certain modifiable factors that have been associated with higher risk of sudden cardiac death. These include short dialysis time, high ultrafiltration rate, and dialysate with a low potassium or calcium concentration. While it is impossible to discern the relative contribution of each of these factors, our review focuses on the role of dialysate potassium concentration in sudden cardiac death. Retrospective studies have identified low potassium dialysate (<2-3 mEq/l) as a risk factor for sudden cardiac death, particularly in patients with predialysis serum potassium concentrations <5 mEq/l. However, patients with predialysis hyperkalemia (≥5.5 mEq/l) may be an exception since a significant association of low potassium dialysate with sudden cardiac death was not observed in this subgroup. Dialysis prescribers must employ alternatives to low dialysate potassium concentrations to achieve potassium control such as increasing dialysis time and frequency, dietary restriction of potassium, prevention and treatment of constipation, discontinuation of medications contributing to hyperkalemia and traditional (or newer, better tolerated) potassium binding resins. Finally, one must also address other factors associated with sudden cardiac death such as short dialysis time, high ultrafiltration rate, and low calcium concentration dialysate.

Clinical implications and outcome prediction in chronic hemodialysis patients with lower serum potassium×uric acid product

BACKGROUND

The aims of this study were to evaluate correlations between serum potassium (S[K]) and uric acid (S[UA]) in hemodialysis patients and to determine whether lower levels of both S[K] and S[UA] were associated with poor long-term prognoses in these patients.

METHODS

A cohort of 424 maintenance hemodialysis patients (58±13 years of age; 47% male; 39% with diabetes) from a single center were divided into tertiles based on the product of S[K]×S[UA] (K×UA): Group 1: low K×UA: n=141; Group 2: median K×UA: n=141; and Group 3: high K×UA: n=142. The longest observation period was 60 months.

RESULTS

S[K] showed a positive linear correlation with S[UA] (r=0.33; p<0.001). In multivariate logistic regression analysis, Group 1 was characterized by hypoalbuminemia (odds ratio [OR]=0.20, 95% confidence interval (CI)=0.11-0.35) and lower levels of normalized protein catabolism [nPCR] (OR=0.10, 95%CI=0.05-0.22) and phosphate levels (OR=0.41, 95%CI=0.33-0.51). In contrast, Group 3 was associated with higher nPCR (OR=6.07, 95%CI=2.93-12.50) and albumin levels (OR=2.12, 95% CI=2.12-7.00). Compared to the reference (Group 1), the hazard ratio (HR) for long-term mortality was significantly lower in Groups 2 (HR=0.65, 95%CI=0.43-0.99) and 3 (HR=0.56, 95%CI=0.36-0.89). In multivariate Cox proportional analysis, the risk of mortality decreased by 2% (HR=0.98; 95%CI=0.96-0.99) per 1 unit increase in K×UA product.

CONCLUSION

Hemodialysis patients with lower S[K] and [UA] levels were characterized by hypoalbuminemia and lower nPCR, and they were associated with a long-term mortality risk.

Changes in potassium and sodium concentrations in stored blood

Potassium is the principal intracellular cation with sodium being the principal extracellular cation. Maintenance of the distribution of potassium and sodium between the intracellular and the extracellular compartments relies on several homeostatic mechanisms. This study analysed the effect of blood storage on the concentrations of potassium and sodium in stored blood and also determine any variations that may exist in their concentrations. 50 mls of blood was sampled each from 28 units of evenly mixed donated blood in citrate phosphate dextrose adenine (CPDA-1) bags immediately after donation into satellite bag and stored at 4oC. Potassium and sodium concentration determinations were done on each of the 28 samples on day 0 (before blood was initially stored in the fridge), day 5, day 10, day 15 and day 20 of storage using the Roche 9180 ISE Electrolyte Analyser (Hoffmann-La Roche Ltd, Switzerland). data analysis showed significant changes in the potassium and sodium concentrations with a continuous rise in potassium and a continuous fall in sodium. A daily change of 0.59 mmol/l and 0.50 mmol/l was observed in the potassium and sodium concentrations respectively. We showed steady but increased daily concentrations of potassium and decrease concentrations of sodium in blood stored over time at 4oC.