Potassium Balance and Acid-Base Changes in Patients Undergoing Regular Haemodialysis Therapy

Serial measurements of total body potassium in 21 patients with chronic renal failure being treated with three 10-hour periods of dialysis per week, against a dialysate fluid containing 1·5 mEq of potassium per litre, showed no evidence of potassium depletion. Mild hyperkalaemia was found in some patients before dialysis, correlated with the pre-dialysis hydrogen ion concentration. Hypokalaemia occurred during dialysis in almost half of the studies made; the plasma potassium concentration, however, rose to normal levels within two to four hours of stopping dialysis. A delay in the movement of potassium from the cells into the extracellular fluid is suggested as a cause for the observed hypokalaemia.In all but one patient the pre-dialysis blood pH was normal, but rose to alkalaemic levels during dialysis. A pronounced degree of hypocapnia was noted before dialysis, and this was not altered by a rising blood pH during dialysis. It is suggested that a stimulus to respiration other than the hydrogen ion gradient between the brain cells and cerebral spinal fluid may produce the observed hypocapnia.     

White blood count in patients on regular haemodialysis

Total white cell, neutrophil, and lymphocyte counts were compared in patients with chronic renal failure treated successively by conservative means (low-protein diet), regular haemodialysis, and renal allotransplantation. The lowest total white cell and neutrophil counts and the highest lymphocyte counts were found in patients on regular haemodialysis. A rapid fall in neutrophil count during the first half-hour of dialysis and a more gradual fall between the first and sixth hours were observed. Adherence of neutrophils and mononuclear cells to the cuprophane (PT 150) dialysis membrane has been shown.     

Inhibitory effects of beta 2-microglobulin on in vitro calcification of osteoblastic cells

Elevated levels of aluminum and beta 2-microglobulin have been demonstrated in chronic dialysis patients. The role of aluminum in the pathogenesis of renal osteodystrophy has also been shown. We report on the effects of beta 2-microglobulin on calcification in vitro using osteoblastic cells, clone MC3T3-El. At concentrations comparable to those in plasma of chronic dialysis patients, both beta 2-microglobulin and aluminum suppressed calcification while collagen synthesis and alkaline phosphatase activity were maintained. These observations may be related to the impaired bone mineralization frequently observed in chronic dialysis patients.     

Evaluation of loss of active heparin in the peritoneal cavity during intermittent peritoneal dialysis]

Our studies aimed at determining a loss of active heparin from the peritoneal cavity after its intraperitoneal administration (250 JU/l of dialysis fluid) in 16 patients treated because of the end-stage renal failure with intermittent peritoneal dialysis and at comparing heparin influx clearance with that of glucose. It has been shown that heparin used in this dose loses 60-70% of its activity after 20-minute equilibration of dialysis fluid in the peritoneal cavity. Heparin influx clearance is higher than that of glucose but it depends on utilization of heparin in peritoneal cavity rather than on its penetration to the blood circulation.     

Does increasing access-to-care delay accessing of care? Evidence from kidney transplantation

Policies increasing healthcare availability might decrease the cost of delaying accessing of care, leading to potential negative consequences if patients delay treatment. We analyze a policy designed to increase access to kidney transplantation through the use of time since dialysis inception to prioritize patients for transplant, which was piloted at 26 of the 271 kidney transplant centers in the United States in 2006 and 2007. We model the patient’s optimization problem comparing the benefits and costs of early waitlisting and predict that the policy change will lead to delayed waitlisting. To empirically test this prediction, we use difference-in-differences fixed effects panel regression techniques to analyze data on patients who began dialysis between 1/1/2000 and 12/31/2009. The results support the model’s prediction; patients on dialysis who waitlist for kidney transplantation increase pre-waitlist dialysis duration by 11.6 percent or approximately 76 days from a pre-policy mean of 652 days (SD = 654). With regard to waitlist outcomes, the policy is associated with a 4.5 percentage point decrease in the probability of receiving a deceased donor transplant, somewhat offset by a 3.0 percentage point increase in the probability of receiving a live donor transplant. On the extensive margin, patients on dialysis decrease their likelihood of ever waitlisting by 1.5 percentage points. We find an increase in pre-waitlist dialysis time and a decrease in the likelihood of waitlisting at all, especially among populations likely to have experienced increased access to transplantation through the policy change: patients self-identifying as Black or Hispanic rather than Non-Hispanic White, and patients without private insurance. These results suggest that some individuals may not benefit if their access to care increases, if the increase in access sufficiently decreases the penalty of delaying accessing of care.     

Automated analysis of free and total concentrations of three antiepileptic drugs in plasma with on-line dialysis and high-performance liquid chromatography

A fully automated method for determination of the free and total concentration of drugs with a varying degree of protein binding is described. The antiepileptic drugs phenytoin, carbamazepine and phenobarbitone were chosen to demonstrate the utility of this technique. The method was based on the ASTED system and combined on-line equilibrium dialysis at 37°C with concentration of the dialysate on a trace enrichment column and HPLC determination with UV detection. The dialysis cell was a modification of the ASTED dialysis cell and 22% of the free concentration of the drugs were recovered in the recipient channel of the dialyser after 10 min of dialysis at 37°C. The free concentration, the total concentration as well as the drugs protein binding could be determined. The method was shown to be well suited for routine monitoring of the free and the total concentrations of the drugs in plasma from epileptic patients.     

A new method for detection of drug-binding proteins using a parallel-flow dialysis technique

A parallel-flow dialysis technique utilizing a Technicon dialyzer and a constant-flow system has been described for the detection of drug-binding proteins. The effect of temperature, flow-rate and drug concentration was investigated by measuring the efficiency of dialysis and detecting the binding of methyl orange to bovine serum albumin. The larger response was shown to be achieved by increasing the efficiency of dialysis or the drug concentration. The present method will enable the continuous monitoring of drug-binding proteins.     

Evaluation of ultra-short dialysis.

A study was carried out to compare the effects of three dialysis regimens of different durations. Nineteen patients dialysed over 1975--7 for an average of only 11.2 hours per week were compared with nine dialysed for 24 hours per week (1974--6) and 10 dialysed for 27 hours (1971--3). Clinical, biochemical, and haematological results showed that the short dialysis regimen was as effective as the longer regimens, except that patients had to take a phosphate binder regularly, and that it was considerably cheaper. Short dialysis has social and economic benefits, since patients have more free time and more patients can be treated with the same number of staff and dialysis stations. As in many areas there is a shortage of places for patients needing dialysis, a short regimen is recommended.     

Protein–solvent interaction

Protein folding and assembly can be manipulated in in vitro systems by co-solvents at high concentrations. A number of co-solvents that enhance protein stability and assembly have been shown to be excluded from the protein surface. Such co-solvent exclusion has been demonstrated by dialysis experiments and shown to be correlated with their effects on protein stability and assembly.     

Not Early Referral but Planned Dialysis Improves Quality of Life and Depression in Newly Diagnosed End Stage Renal Disease Patients: A Prospective Cohort Study in Korea

BackgroundHealth-related quality of life (HRQOL) has recently become an important issue. It reportedly affects morbidity and mortality in patients with end-stage renal disease (ESRD). In this study, we investigated whether early referral and planned dialysis improve the HRQOL and depression of patients with ESRD.MethodsWe prospectively enrolled newly diagnosed patients with ESRD, from 31 hospitals in Korea, who completed questionnaires at 3 months after dialysis. We also got follow-up survey at 1 year after dialysis. To measure HRQOL and depression, Kidney Disease Quality of Life Short Form 36 (KDQOL-36) and Beck’s Depression Inventory (BDI) were utilized.ResultsA total of 643 patients were analyzed. Referral type did not affect either KDQOL-36 or BDI scores. However, the planned dialysis group showed significantly better scores in 4 of 5 KDQOL-36 domains than did the unplanned group at 3 months after dialysis and partly, the effect was sustained for 1 year after dialysis. The benefit of planned dialysis was significant after adjusting for age, sex, type of dialysis, marital status, educational attainment, occupation, modified Charlson comorbidity index, albumin, and hemoglobin levels. BDI scores were also lower which indicate less depressive mood in planned dialysis group than those in unplanned group both at 3 months and 1 year after dialysis.ConclusionsNot early referral but planned dialysis improved both the short- and long-term HRQOL and depression of patients with ESRD. Nephrologists should try to help patients to initiate dialysis in a planned manner.     

A novel dialysis procedure for the crystallization of proteins

Various dialysis methods are commonly employed for the crystallization of proteins. Typical procedures include the use of dialysis bags, dialysis buttons or Zeppezauer microdiffusion cells. The general principle involved is that the protein solution is gradually brought to a point of supersaturation by imposing a gradient of ionic strength or organic solvent concentration across the wall of the dialysis membrane. However, in some cases, the imposition of this gradient across the dialysis membrane can result in the formation of a large number of crystal nucleation sites, thereby giving rise to a reduction in the maximum size of the crystals which can be obtained. A novel 'double-dialysis' procedure which incorporates a second dialysis membrane, thus reducing the rate of equilibration in the crystallization experiment, has been developed in our laboratory. The system has been employed successfully on the delta toxin of Staphylococcus aureus resulting in a useful increase in crystal size. A more quantitative analysis of the technique has been carried out on rat liver malic enzyme. The results of a limited series of crystallization trials with this protein have shown that employment of the 'double-dialysis' technique allows a fine control of the rate of crystal nucleation and therefore provides a mechanism for the controlled growth of large crystals.     

Blood level of free serotonin, catecholamines and the renin-angiotensin-aldosterone system in patients with primary hypertension]

Two subgroups of patients were selected out of those dialysed for chronic renal failure. Group A included patients without arterial hypertension before dialysis, and group B patients with arterial hypertension before dialysis. Blood endogenous digoxin-like substance (DLS) has been assayed. Its blood levels were not increased in hypertensive patients either before or after dialysis. No correlation was found between DLS and mean arterial pressure in the whole group of patients with chronic renal failure. The obtained results do not suggest that arterial blood pressure in patients with chronic renal failure is related to the presence of DLS in the blood.     

Reconstitution of liver endoplasmic reticulum membranes from solubilized proteins and lipids by removal of detergent]

A method for membrane reconstitution from cholate-solubilized microsomal proteins and lipids by a removal of the detergent on a column with charcoal has been developed. A comparative study showed that the membranes reconstituted by a dialysis or absorption do not differ from each other in terms of membrane proteins incorporation into lipid vesicles and cytochrome P-450 reconversion into cytochrome P-450. A possibility of biomembrane reconstitution from membrane proteins and lipids solubilized by a non-ionic detergent Triton X-100 was shown. A removal of the detergent results in a formation of membranes, which are chemically close to the original ones but ultrastructurally very different from the latter. On the other hand, absorption or dialysis of cholate-solubilized proteins and lipids results in reconstituted membranes with asymmetrically arranged intramembrane particles located on the hydrophobic surfaces of the membrane halves. The number and size of these particles are similar to those of the original microsomal membranes.     

Rapid determination of valaciclovir and acyclovir in human biological fluids by high-performance liquid chromatography using isocratic elution

A rapid high-performance liquid chromatographic assay with isocratic elution is developed for the simultaneous quantification of valaciclovir (VACV) prodrug and its active converted compound, acyclovir (ACV), in biological fluids of treated patients. For serum, the samples are deproteinized with perchloric acid in presence of 1-methylguanosine as the internal standard (IS). For urine and dialysis liquid, the samples are diluted with a mobile phase containing the IS, then filtered. VACV, ACV and the IS are separated on a SymmetryShield™ RP-8 column with acetonitrile–ammonium phosphate buffer as the mobile phase and detected at 254 nm. The chromatographic time is about 12 min. The relative standard deviations (RSD) of VACV and ACV standards are between 0.5 and 3.5%. Most endogenous nucleosides and their metabolites, psychotropic drugs and drugs of abuse are shown not to interfere with this technique. The method has been applied to study the pharmacokinetics of VACV and ACV in serum, dialysis liquid and urine of renal failure patients on continuous ambulatory peritoneal dialysis (CAPD) under oral treatment of VACV.     

Statistical Approach to Planning an Integrated Haemodialysis/Transplantation Programme

A mathematical model has been constructed to assist in planning the future requirements of a combined haemodialysis and transplantation centre. It has been used to predict the number of patients in the dialysis unit, the general wards, and at home on dialysis, as well as providing further information on transplantation rates and overall costs. The model can be adapted for units with different facilities from our own.It can be primed with data from an individual unit or with pooled data from the whole country. The purpose of this paper is to demonstrate the methodology of a particular statistical approach.     

The permanent Tenckhoff catheter for chronic peritoneal dialysis.

Over a 3 1/2-year period the permanent Tenckhoff catheter was used in 66 patients (32 men and 34 women) maintained on chronic peritoneal dialysis for periods from 2 1/2 to 36 1/2 months; 57 patients had dialysis in hospital for 20 to 24 hours twice a week and the other 9 had dialysis at home for 10 to 12 hours four times a week. While the Tenckhoff catheter was in place 14 patients received a renal transplant; for 13 who required peritoneal dialysis during the post-transplant phase the Tenckhoff catheter was used. In nine patients abdominal surgery did not interfere with the continuation of peritoneal dialysis via the Tenckhoff catheter. From a total of 5067 dialyses 40 positive cultures were reported (0.8%). Peritonitis was clinically evident on only 14 occasions (0.28%). Permanent catheter obstruction developed in 16 patients, in 11 of whom it was related to peritonitis. With the introduction of the permanent Tenckhoff catheter long-term peritoneal dialysis has become a simple, safe and painless procedure, suitable for virtually all patients who require maintenance dialysis.     

Integrated dialysis and renal transplantation: small is beautiful.

Many patients in Britain with chronic renal failure suitable for renal replacement treatment die because not enough treatment facilities are available. Moreover, the number of renal transplants performed is insufficient to meet even present needs, so the number of patients on dialysis is rising. The integrated dialysis and transplant unit in Aberdeen, which has a population base much smaller than the average British unit, meets community needs for dialysis and transplantation. The problem of harvesting cadaver kidneys has been solved; the present supply has not only enabled the number of patients on dialysis to remain stable but has resulted in a net export of kidneys. The Aberdeen unit shows how estimated needs for chronic dialysis and renal transplantation may be met.     

Effect of long term dialysis therapy on blood prolactin patients with chronic renal failure

An effect of dialysis therapy on baseline prolactinemia and prolactinemia following suppression test with alpha-bromocriptine was determined in 34 patients with chronic renal failure. Gradual decrease in hyperprolactinemia with the duration of dialysis therapy has been observed. Prolactinemia baseline values in patients dialysed for 100 months did not differ from those determined in healthy individuals.     

Changes in survival among elderly patients initiating dialysis from 1990 to 1999

Background

Over the past decade, there has been a steep rise in the number of people with complex medical problems who require dialysis. We sought to determine the life expectancy of elderly patients after starting dialysis and to identify changes in survival rates over time.

Methods

All patients aged 65 years or older who began dialysis in Canada between 1990 and 1999 were identified from the Canadian Organ Replacement Register. We used Cox proportional hazards models to examine the effect that the period during which dialysis was initiated (era 1, 1990–1994; era 2, 1995–1999) had on patient survival, after adjusting for diabetes, sex and comorbidity. Patients were followed from initiation of dialysis until death, transplantation, loss to follow-up or study end (Dec. 31, 2004).

Results

A total of 14 512 patients aged 65 years or older started dialysis between 1990 and 1999. The proportion of these patients who were 75 years or older at the start of dialysis increased from 32.7% in era 1 (1990–1994) to 40.0% in era 2 (1995–1999). Despite increased comorbidity over the 2 study periods, the unadjusted 1-, 3- and 5-year survival rates among patients aged 65–74 years at dialysis initiation rose from 74.4%, 44.9% and 25.8% in era 1 to 78.1%, 51.5% and 33.5% in era 2. The respective survival rates among those aged 75 or more at dialysis initiation increased from 67.2%, 32.3% and 14.2% in era 1 to 69.0%, 36.7% and 20.3% in era 2. This survival advantage persisted after adjustment for diabetes, sex and comorbidity in both age groups (65–74 years: hazard ratio [HR] 0.76, 95% confidence interval [CI] 0.72–0.81; 75 years or more: HR 0.86, 95% CI 0.80–0.92).

Interpretation

Survival after dialysis initiation among elderly patients has improved from 1990 to 1999, despite an increasing burden of comorbidity. Physicians may find these data useful when discussing prognosis with elderly patients who are initiating dialysis.Within general medical and subspecialty areas, chronic kidney disease is increasingly recognized as an important comorbid condition that is often associated with prolonged hospital stays and increased morbidity and mortality.^1–3 As a result, internists and other specialists are more likely than before to be involved with the care of patients for whom dialysis needs to be started because of end-stage kidney disease. The majority of patients starting dialysis are 65 years or older at the time of their first treatment, and many are over 75 years.⁴ Given the heightened awareness of chronic kidney disease, its high prevalence, the association with multiple comorbidity, and the impact of dialysis on survival and quality of life, we sought to calculate the mean life expectancy of elderly patients who began dialysis at either 65–74 years of age or at 75 years or more, and to identify whether there was any change in survival probability, or in the effect of comorbidity characteristics, on dialysis over the past decade.