Clinical characterization of a new polymeric membrane for use in renal replacement therapy

Can an intradialytic snack model compensate the catabolic impact of hemodialysis?

BACKGROUND AND AIMS

Hemodialysis (HD) has a catabolic effect caused by alterations in protein metabolism, increase in resting energy expenditure (REE) and protein needs due to inflammation, HD circuit blood and heat losses, protein losses to dialysate and HD filter membrane biocompatibility. We aim to determine, as a proof of concept, whether a standardized intradialytic snack model is adequate to compensate the catabolic impact of HD.

METHODS

Cross sectional analysis of patients' chosen intradialytic intake according to a snack model, at the day of blood sample collection of three different months. As targets for the compensation of the catabolic impact of HD, we considered 316.8kCal (1.32 (±0.18) kcal/min - 240' of HD) for the estimated increase in REE and at least 7 g of protein losses/HD treatment.

RESULTS

A total of 448 meals were analyzed, with 383 given during daytime shifts. No intolerances were registered. The mean nutritional profile of the daytime shifts intakes was 378.8 (±151.4) kcal, 13.5 (±7.2) g of protein, 676 (±334) mg of sodium (Na), 361.0 (±240.3) mg of potassium (K) and 249.3 (±143.0) mg of phosphates (P). We found that 68% of the meals provided an intake ≥316.8kCal and 82% a protein intake ≥ 7 g, with a significant association found between treatment shift and energy (p < 0.028), protein (p < 0.028), lipids (p < 0.004), Na (p < 0.004), K (p < 0.009) and P (p < 0.039) intakes.

CONCLUSIONS

We found that this intradialytic snack model meets the target for the treatment-related increases in protein and energy needs. Although sodium intake was found to be high, potassium and phosphate intake was considered adequate.

Dialysis-related thrombocytopenia: a case report

Thrombocytopenia is frequently observed in hemodialysis patients, and its correct investigation and control remain a challenge. It is estimated that during the hemodialysis session there is a drop of up to 15% in the platelet count, with recovery after the end of treatment. This reduction in platelets is due to platelet adhesion and complement activation, regardless of the membrane material. Several studies with platelet surface markers demonstrate increased platelet activation and aggregation secondary to exposure to cardiopulmonary bypass. This case report describes a patient on hemodialysis who developed severe thrombocytopenia during hospitalization. Investigation and exclusion of the most common causes were carried out: heparin-related thrombocytopenia, adverse drug reaction, hypersplenism, and hematological diseases. Afterwards, the possibility of hemodialysis-related thrombocytopenia was raised, since the fall was accentuated during the sessions with partial recovery after the dialyzer change. Attention to the sterilization method and dialyzer reuse must be considered for correction. In the current case, reusing the dialyzer minimized the drop in platelet counts associated with hemodialysis.

Differences and Effects of Metabolic Fate of Individual Amino Acid Loss in High-Efficiency Hemodialysis and Hemodiafiltration

OBJECTIVE

The objective of the study was to quantify the loss and arterial blood concentration of the three main classes of amino acids (AAs)-nonessential amino acids (NEAAs), essential amino acids (EAAs), and branched-chain amino acids-as resulting from high-efficiency hemodialysis (HED) and hemodiafiltration (HDF). We moreover aimed to identify the different fates and metabolic effects manifested in patients undergoing hemodialysis and the consequences on body composition and influence of nutritional decline into protein energy wasting.

DESIGN AND METHODS

Identical dialysis monitors, membranes, and dialysate/infusate were used to ensure consistency. Ten patients were recruited and randomized to receive treatment with on-line modern HED and HDF. Arterial plasma concentrations of individual AAs were compared in healthy volunteers and patients undergoing hemodialysis, and AA levels outflowing from the dialyzer were evaluated. Baseline AA plasma levels of patients undergoing hemodialysis were compared with findings obtained 1 year later.

RESULTS

A severe loss of AA with HED/HDF was confirmed: a marked loss of total AAs (5 g/session) was detected, corresponding to more than 65% of all AAs. With regard to individual AAs, glutamine displayed a consistent increase (+150%), whereas all other AAs decreased after 12 months of HD/HDF. Only a few AAs, such as proline, cysteine, and histidine maintained normal levels. The most severe metabolic consequences may result from losses of EAAs such as valine, leucine, and histidine and from NEAAs including proline, cysteine, and glutamic acid eliciting the onset of hypercatabolism threatening muscle mass loss.

CONCLUSION

Dialysis losses, together with the effect of chronic uremia, resulted in a reduction of fundamental EAAs and NEAAs, which progressively led our patients after 12 months to a deterioration of lean mass toward sarcopenia. Therefore, the reintroduction of a correctly balanced AA supplementation in patients undergoing HD to prevent or halt decline of hypercatabolism into cachexia is recommended.

Effect of different hemodialyzers on serum levels of interleukin-6, interleukin-10 and interleukin-18

BACKGROUND

The blood and membrane contact during dialysis may elicit an immune reaction. The current study looked at the impact of different dialyzers on blood levels of cytokines.

METHODS

During the first month, randomly selected patients were treated with one dialyzer (PF-170H) and then crossed over to another dialyzer (FLX-18GW) during the next month. Pre- and postdialysis blood samples were assayed for interleukin (IL)-6, IL-10 and IL-18.

RESULTS

A significant drop of postdialysis systolic blood pressure (pre vs. post 156.4 ± 31.8 vs. 143.1 ± 24.8 mm Hg, p = 0.014) and diastolic pressure (80.7 ± 12.7 vs. 73.4 ± 10.9 mm Hg, p = 0.002) were found when patients were dialyzed with PF-170H. A significant increase of postdialysis IL-18 levels was found in both groups (pre vs. post 605.5 ± 278.6 vs. 690.6 ± 315.3 pg/ml, p = 0.016, for PF-170H and 556.4 ± 231.0 vs. 647.3 ± 282.6 pg/ml, p = 0.067, for FLX-18GW). There was a positive correlation between IL-6 and IL-10 levels (p < 0.0001).

CONCLUSION

We demonstrated a significant increase of postdialysis serum IL-18 level when either dialyzer was used. There is a strong correlation between serum levels of IL-6 and IL-10.

Evaluation of polyethersulfone highflux hemodialysis membrane in vitro and in vivo

A new hemodialysis membrane manufactured by a blend of polyethersulfone (PES) and polyvinylpyrrolidone (PVP) was evaluated in vitro and in vivo. Goat was selected as the experimental animal. The clearance and the reduction ratio after the hemodialysis of small molecules (urea, creatinine, phosphate) for the PES membrane were higher in vitro than that in vivo. The reduction ratio of beta(2)-microglobulin was about 50% after the treatment for 4 h. The biocompatibility profiles of the membranes indicated slight neutropenia and platelet adhesion at the initial stage of the hemodialysis. Electrolyte, blood gas, and blood biochemistry were also analyzed before and after the treatment. The results indicated that PES hollow fiber membrane had a potential widely use for hemodialysis.

C-reactive protein as predictor of death in end-stage diabetic nephropathy: role of peripheral arterial disease

BACKGROUND

Patients with diabetes type 2 receiving dialysis therapy have a poor survival prognosis, mainly due to cardiovascular events. Increased C-reactive protein (CRP) levels, important in atherosclerosis, are associated with an increased risk for cardiovascular events. However, to date no study has shown the predictive value of CRP in relation to peripheral arterial disease stage.

METHODS

We enrolled all 445 prevalent patients with diabetic nephropathy receiving maintenance hemodialysis in 30 centers in Southern Germany from August 1999 to January 2000 for prospective study until December 2003. At inclusion, CRP and a complete clinical phenotype, including peripheral arterial disease Fontaine Stage were determined. The primary end point was all-cause mortality.

RESULTS

A total of 305 (68.5%) patients died. An increased log CRP at study inclusion was significantly associated with an increase in hazard ratio (HR) by multivariate Cox regression for all-cause (HR = 1.5, P= 0.002) and cardiac death (HR = 1.76, P= 0.02) in the entire collective. This result was applicable only to patients with peripheral arterial disease Fontaine stage IV (N= 190, multivariate HR = 1.75 for all-cause mortality, P= 0.006). Possibly due to inadequate power, we observed only an insignificant trend for CRP as predictor of all-cause death in patients without peripheral arterial disease or with less severe forms of peripheral arterial disease (HR = 1.36, P= 0.08).

CONCLUSION

In contrast to patients with peripheral arterial disease stage IV, patients with less severe atherosclerosis and elevated CRP are, if any, at less risk for cardiovascular mortality, possibly due to the difference in extent of affected vasculature and thus activated platelets and coagulation. Before judging the predictive value of CRP for mortality, peripheral vessel status should be determined.

Severe acute respiratory syndrome in a hemodialysis patient

Severe acute respiratory syndrome (SARS) is a highly infective disease caused by a newly identified coronavirus. We described the clinical course of the first long-term hemodialysis patient who developed SARS in the literature, and our experience in performing hemodialysis for this patient. Such patients may present with a less typical clinical picture, making diagnosis difficult. In this patient, the course of disease and duration of viral shedding was apparently prolonged, thus highlighting the need for increased infection control. Despite worsening the anemia in renal failure patients by causing hemolysis, ribavirin is well tolerated after dosage adjustment. Difficulties of diagnosis, infection control, and treatment of SARS in renal failure patients are discussed in this report.