Lipopolysaccharide concentrations during superflux dialysis using unfiltered bicarbonate dialysate

Prolonged Daily Intermittent Renal Replacement Therapy in ICU Patients by ICU Nurses and ICU Physicians

Objectives

Prolonged daily intermittent renal replacement therapy (PDIRRT) has been proposed as a new form of treatment for severe acute renal failure (ARF). However, this treatment has so far implied a) full dependence on nephrological input, b) lack of any convective clearance and c) limited purification of dialysate water. The aim of this study was to establish the feasibility and safety of performing PDIRRT in the ICU with a) no nephrological input, b) the addition of some convective clearance with on-line fluid replacement and c) a new advanced water purification system.

Design

Prospective observational study.

Patients

Fourteen patients treated with PDIRRT.

Setting

ICU of tertiary institution.

Interventions

Treatment of patients with severe ARF and critical illness with PDIRRT. Prescription of treatment by ICU physicians. Conduct of treatment by ICU nurses. Use of combined convective and diffusive therapy with on-line generation of fluid replacement, application of a double-filtration water purification system.

Measurements and Main Results

We prospectively collected demographic, biochemical, hemodynamic and clinical data in 14 patients, who received 30 PDIRRT treatments for a cumulative treatment time of 205.4 hours. The mean age was 57.9 ± 16.0. Eight patients were male and 6 female. Their mean APACHE II score was 24.6 ± 5.9 and their SAPS II score was 41.7 ± 18.8. PDIRRT was used after at least 24 hours of initial stabilization with continuous veno-venous hemofiltration (CVVH). Blood flow was kept at 100ml/min dialysate flow at 200 ml/min and convective clearance varied from 21 ml/min to 33 ml/min. All patients were either anuric or oliguric (UO < 400 ml/day). Ten patients were on mechanical ventilation and 11 patients on vasopressor support. Mean treatment session time was 6.9 ± 1.8 hours. The mean pre-PDIRRT urea was 19.2 ± 6.9 mmol/L and the creatinine was 274 ± 116 μmol/L. The mean pre-PDIRRT lactate was 2.95 ± 2.24 mmol/L. Following treatment, all had significantly decreased to 13.2 ± 6.3 mmol/L, 215 ± 95 μmol/L and 2.25 ± 1.61 mmol/L, respectively (p=<0.0001, <0.0001, <0.05). Bicarbonate levels remained stable during treatment (23.0 ± 3.8 mmol/L to 23.1 ± 2.5 mmol/L). Mean norepinephrine dose changed from 8.8 ± 11.9 μg/min to 12.9 ± 27.0 μg/min after treatment (NS). There were no complications of therapy. Patient ICU survival was 71.4%.

Conclusions

PDIRRT with combined diffusive and convective clearance is an efficacious form of renal replacement, which can be safely and effectively conducted by ICU nurses following prescription by ICU physicians without any nephrological involvement and with adequate double filtration water purification.

Enhanced long-term reduction of plasma leptin concentrations by super-flux polysulfone dialysers

BACKGROUND

Hyperleptinaemia in chronic haemodialysis (CHD) patients has been associated with malnutrition, which is an independent predictor of morbidity and mortality in this patient group.

METHODS

To assess the influence of HD on plasma leptin, 10 CHD patients were crossover randomized to low-flux polysulfone (PS: F 6HPS), high-flux PS (F 60S), super-flux PS (F 500S) or super-flux cellulose-tri-acetate (CTA: Tricea 150G) for 12 weeks each. Blood samples were collected at the start of the study and each 12-week period. In addition, the relationship between patient characteristics, inflammation and leptin was analysed.

RESULTS

At baseline, all groups showed similar leptin concentrations (mean 33.6+/-21.7 ng/ml). After a single HD session, a significant (P<0.01) decrease was observed with all three high permeable devices (Tricea 150G -52.7+/-6.4%; F 60S -63.1+/-5.7%; F 500S -68.7+/-8.2%), whereas leptin remained stable with low-flux PS. After 12 weeks, a marked increase was observed with low-flux PS (week 1, 30.4+/-23.0; week 12, 40.5+/-5.4 ng/ml, P = 0.05), no change with super-flux CTA and high-flux PS (Tricea 150G week 1, 29.4+/-23.7; week 12, 32.0+/-27.9 ng/ml, P = ns; F 60S week 1, 36.0+/-31.8; week 12, 33.0+/-31.2 ng/ml, P = ns), and a significant decrease with super-flux PS (week 1, 38.3+/-33.0; week 12, 29.5+/-31.9 ng/ml, P = 0.02). The change in leptin after 12 weeks was significantly different between super-flux PS, and both low-flux PS (P = 0.009) and super-flux CTA (P = 0.01). Besides interleukin-6 (IL-6) at the start of the study (P = 0.006), no correlations were observed between patient characteristics, parameters of inflammation and plasma leptin levels.

CONCLUSIONS

Apart from low-flux PS, plasma leptin decreased considerably with all three high permeable dialysers after a single HD session. In the long run, leptin levels were lower with high-flux PS than with low-flux PS. Moreover, after switching from high-flux PS to super-flux PS (but not super-flux CTA), an additional decrease in leptin was observed. Apart from IL-6 at the start of the study, neither patient characteristics nor inflammatory parameters correlated with plasma leptin levels in this patient group.