Management of hypophosphatemia in nocturnal hemodialysis with phosphate-containing enema: a technical study.

Hypophosphatemia is observed in patients undergoing nocturnal hemodialysis. Phosphate is commonly added to the dialysate acid bath, but systematic evaluation of the safety and reliability of this strategy is lacking. The objectives of this study were 4-fold. First, we determined whether predictable final dialysate phosphate concentrations could be achieved by adding varying amounts of Fleet® enema. Second, we assessed the stability of calcium (Ca) and phosphate dialysate levels under simulated nocturnal hemodialysis conditions. Third, we assessed for Ca-phosphate precipitate. Finally, we evaluated whether dialysate containing Fleet® enema met the current sterility standards. We added serial aliquots of enema to 4.5 L of dialysate acid concentrate and proportioned the solution on Gambro and Althin/Baxter dialysis machines for up to 8 hours. We measured dialysate phosphate, Ca, pH, and bicarbonate concentrations at baseline, and after simulated dialysis at 4 and 8 hours. We evaluated for precipitation visually and by assessing optical density at 620 nm. We used inoculation of agar to detect bacteria and Pyrotell reaction for endotoxin. For every 30 mL of Fleet® (1.38 mmol/mL of phosphate) enema added, the dialysate phosphate concentration increased by 0.2 mmol/L. There were no significant changes in dialysate phosphate, Ca, pH, and bicarbonate concentrations over 8 hours. No precipitate was observed in the dialysate by optical density measures at 620 nm for additions of up to 90 mL of enema. Bacterial and endotoxin testing met sterility standards. The addition of Fleet® enema to dialysate increases phosphate concentration in a predictable manner, and no safety problems were observed in our in vitro studies.

Risk factors for increased variability in dialysis delivery in haemodialysis patients.

BACKGROUND: Numerous events may occur during a haemodialysis session, leading to variation in the quantity of dialysis received. The purpose of this study was to identify risk factors for variability in haemodialysis delivery. METHODS: Variability in dialysis delivery was expressed by the coefficient of variation (CV%) and calculated for the volume of blood processed (VBP) for all treatments and the monthly urea reduction ratio (URR) in each patient over an 8 month period. The univariate and multivariate relationships between various predictor variables and the URR and VBP CV% were determined. RESULTS: Eighty-nine patients were identified who met study criteria. The mean VBP and URR CV% were 10.3 +/- 4.7 and 5.4 +/- 3.8%, respectively. Patients with tunnelled catheters and total nursing-care patients had higher VBP and URR CV%, as evaluated by multivariate analysis. Patients with inadequate dialysis (mean URR <65%) had a higher VBP CV% than those patients with mean URR values > or =65% (14.8 +/- 5.4 vs 9.7 +/- 4.5%; P = 0.01). An accurate determination of the URR in 90% of patients required 14 measurements in patients with catheters vs three and two measurements in arteriovenous fistulae and polytetrafluoroethylene grafts, respectively. CONCLUSIONS: This study demonstrated that the use of a venous tunnelled catheter and dialysis in a total nursing-care unit were the only factors independently associated with greater variability in both VBP and URR. Attention to individual dialysis sessions in patients with tunnelled catheters or in a total nursing-care unit is prudent, particularly when identifying reasons for under-dialysis.

Protocolized anemia management with erythropoietin in hemodialysis patients: a randomized controlled trial.

Treatment of the anemia of chronic renal failure with exogenous recombinant human erythropoietin (rHuEpo) is well established. The objective of this randomized clinical trial was to evaluate an anemia management team protocol in hemodialysis patients, using subcutaneous rHuEpo and intravenous iron. A total of 215 patients were randomized to either usual care or the protocol. The primary outcome was the proportion of patient hemoglobin (Hgb) values between 11.0 and 12.5 g/dl over the final 8 wk. The study was halted after 240 d because of an institutional change to intravenous rHuEpo. The proportion of Hgb values in the target range increased from 47.4% to 62.8% overall (P = 0.001); there was no difference between treatment groups. The proportion of baseline Hgb values between 11.0 and 12.5 g/dl increased from 44.6% in patients who had enrolled within the first 3 mo of study inception to 75.0% in those who started later (P = 0.017), suggesting a Hawthorne effect. A nonsignificant decrease in rHuEpo dose was observed in the protocol group; subgroup analysis in patients who were enrolled for at least 5 mo demonstrated a reduction in the rHuEpo dose of 2788 units/wk in the protocol group (P < 0.05), independent of intravenous iron dose. Multivariate analysis demonstrated that a higher transferrin saturation and albumin and protocol group assignment were associated with a lower final rHuEpo dose. This study demonstrated that a protocolized approach to anemia management in hemodialysis patients results in comparable Hgb levels and may reduce rHuEpo requirements, independent of iron use.

Comparison of volume of blood processed on haemodialysis adequacy measurement sessions vs regular non-adequacy sessions.

BACKGROUND: Knowledge that adequacy measures such as the urea reduction ratio (URR) or Kt/V(urea) are being measured on haemodialysis may influence the behaviour of patients or staff such that the treatment may be better on those days. This study therefore tested the hypothesis that mean volume of blood processed (VBP), utilized as a surrogate for adequacy, is higher on adequacy measurement days than non-measurement days. METHODS: Patients were identified who had been on haemodialysis over the preceding 8 months. Primary outcome was the difference in the mean VBP (in litres) on URR measurement compared with non-URR measurement days (DeltaVBP(U)(-N)). Univariate and multivariate correlates of mean VBP and DeltaVBP(U)(-N) were also determined. RESULTS: Eighty-nine patients were identified who met inclusion and exclusion criteria. Linear regression demonstrated a weak relationship between VBP and URR (r=0.24, P<0.02). This relationship was much stronger when VBP was adjusted for patient weight (mean VBP/weight; r=0.78, P<0.0001). The overall mean VBP was 87.4 l (+/-1.2 l) and the average DeltaVBP(U)(-N) was 1.1 l (+/-0.3 l) (P=0.001). Twenty per cent of patients had a clinically relevant DeltaVBP(U)(-N) of >3.6 l. Patients with a graft or fistula had a significantly higher DeltaVBP(U)(-N) than patients with a tunnelled catheter. CONCLUSIONS: This study demonstrates that the average VBP is less on non-URR than on URR measurement days; this difference was clinically important in >20% of patients. Univariate analysis indicated that the use of a fistula or graft correlated with a higher DeltaVBP(U)(-N). This implies that our current method of assessing dialysis adequacy does systematically overestimate the average delivered dose of dialysis in a subset of patients.