Efficacy of enoxaparin in preventing coagulation during high-flux haemodialysis, expanded haemodialysis and haemodiafiltration

Background Low-molecular-weight heparins (LMWHs) are easily dialysable with high-flow membranes; however, it is not clear whether the LMWH dose should be adjusted according to the membrane type and dialysis technique. This study aimed to evaluate the influence of the dialyser on anticoagulation of the extracorporeal dialysis circuit. Methods Thirteen patients received the same dose of LMWH through the arterial port via three dialysis techniques: high-flux haemodialysis (HF-HD), online haemodiafiltration (HDF) and expanded haemodialysis (HDx). All dialysis was performed under similar conditions: duration, 4 h; blood flow, 400 mL/min; and dialysate flow, 500 mL/min. Antifactor Xa (aXa) activity and activated partial thromboplastin time (APTT) were measured before and after the dialysis. Clotting time of the vascular access site after haemodialysis, visual clotting score of the dialyser and any complications with the extracorporeal circuit or bleeding were registered. Results Post-dialysis aXa activity in HF-HD (0.26 ± 0.02 U/mL) was significantly different from that in HDF (0.21 ± 0.02 U/mL, P = 0.024), and there was a trend in HDx (0.22 ± 0.01 U/mL, P = 0.05). APTT post-dialysis in HF-HD (30.5 ± 0.7 s) was significantly different from that in HDx (28.2 ± 0.64 s, P = 0.009) and HDF (28.8 ± 0.73 s, P = 0.009). Conclusions AXa activity in HDF was significantly lower than that in HF-HD, possibly because of more losses of LMWH through the dialyser. Given the higher anticoagulant loss in HDF and probably in HDx than in HF-HD, the enoxaparin dose administered may be adjusted according to the dialysis technique.

P1369ACUTE EXTRACORPOREAL DIALYSIS USING TWO-WAY PICC POWER INJECTABLE IN YOUNG CHILDREN

Background and Aims Acute extracorporeal dialysis is a short treatment, performed by a central venous catheter of large size, ensuring high flow. These devices have limitations: high caliber, excessive length, impossibility of tunneling and exit-site location in the supraclavicular region, with a subsequent high risk of dislocation and contamination. The authors report a new approach to dialytic central venous catheters selection in children. Method From January 2013 to December 2017, 16 children weighing less than 15 kg needed acute extracorporeal dialysis. Patients received an ultrasound guided percutaneous implantation of a two-way PICC power injectable catheter, in the right internal jugular vein or in the anonymous right vein. The device size always respected the ratio of 1/3; the catheters were cut to be adapted to child height, and subclavear tunnelizations and stabilizations were ensured. The hemodialysis was performed with the Prismaflex Gambro system. The effectiveness of treatment was evaluated by recirculation test and by measuring the KT/Vat the third hour, expressing the dialysis adequacy. Results Two-way power injectable central venous catheter,sized from 5 to 7 Fr and long from 8 to 15 cm were used. The recorded blood flow ranged from 4.7ml/min/kg to 7ml/min/kg; a KT/V variable from 0.5 to 1 was detected; the recycling rate was between 32% and 40%. No catheter related complications were observed. Conclusion In children weighing less than 15 kg, PICC power injectable have lower blood flow and higher recirculation rate compared to traditional dialysis catheters. However, the dialytic adequacy was suitable for an acute hemodialysis treatment. In addition, these catheters are available in a wide range of calibers and result more adaptable to the venous system of younger children.

The production of on-line dialysis water for extracorporeal dialysis: proposals for an increased safety upgrade: a viewpoint

Introduction At the start of the 2000s, the progressive diffusion of high-flux extracorporeal dialysis and membranes saw an increased use of high infusion volumes injected into the patient’s blood circuit following the advent of on-line water production plants. Methodology Our 15-year experience with on-line extracorporeal methodologies using very high infusion volumes has led to the detection of errors and weaknesses, thus allowing us to correct and provide for the implementation of appropriate technology in dialysis water production plants with the aim of ensuring a higher chemical-physical, bacteriological and endotoxin quality. The initial procedures had already been outlined in the 2005 Italian Guidelines, although still today Health Technicians and Nephrologists operating in the field are unable to take on board specific integrations for on-line methods due to a lack of upgrading of documentation in both European and non-European Guidelines. Results After more than 17 years’ experience, and in view of the technological implementations developed since 2005, we wish to put forward a series of suggestions in an attempt to improve the safety of on-line water, with uses ranging from drinking water, pre-treatment, osmosis, distribution circuit, hemodialysis monitors up to the most recent update of microbiological cultures. Discussion Additional, more stringent measures are required to prevent the occurrence of acute accidents during dialysis sessions and to reduce chronic inflammation-oxidation deriving from the use of not totally ultra-pure/sterile dialysis fluids. Conclusion Our point of view based on our long-standing experience, the proposals made relate to procedures to be applied in technological maintenance, which the consultant nephrologist and other relevant personnel such as microbiologists, biologists, and technical operators should adhere to rigorously to ensure that the production of dialysis water on-line is viewed on a par with a pharmacological administration.

Differences in Dialysis Efficacy Have Limited Effects on Protein-Bound Uremic Toxins Plasma Levels over Time

The protein-bound uremic toxins para-cresyl sulfate (pCS) and indoxyl sulfate (IS) are associated with cardiovascular disease in chronic renal failure, but the effect of different dialysis procedures on their plasma levels over time is poorly studied. The present prospective, randomized, cross-over trial tested dialysis efficacy and monitored pre-treatment pCS and IS concentrations in 15 patients on low-flux and high-flux hemodialysis and high-convective volume postdilution hemodiafiltration over six weeks each. Although hemodiafiltration achieved by far the highest toxin removal, only the mean total IS level was decreased at week three (16.6 ± 12.1 mg/L) compared to baseline (18.9 ± 13.0 mg/L, p = 0.027) and to low-flux dialysis (20.0 ± 12.7 mg/L, p = 0.021). At week six, the total IS concentration in hemodiafiltration reached the initial values again. Concentrations of free IS and free and total pCS remained unaltered. Highest beta2-microglobulin elimination in hemodiafiltration (p < 0.001) led to a persistent decrease of the plasma levels at week three and six (each p < 0.001). In contrast, absent removal in low-flux dialysis resulted in rising beta2-microglobulin concentrations (p < 0.001). In conclusion, this trial demonstrated that even large differences in instantaneous protein-bound toxin removal by current extracorporeal dialysis techniques may have only limited impact on IS and pCS plasma levels in the longer term.

Safety and Efficacy of Tinzaparin Anticoagulation during Nocturnal Hemodialysis

Background: The safety and efficacy of low-molecular-weight heparin in the prevention of extracorporeal dialysis circuit clotting among in-center extended duration nocturnal hemodialysis (INHD) patients are unknown. The aim of this study was to determine the safety and efficacy of 2 doses of tinzaparin, among INHD patients receiving 6–8 h hemodialysis, 3 times per week. Methods: We conducted a retrospective cohort study to examine antifactor Xa levels at time 0, 2 h, 4 h mid-hemodialysis (mid-HD), 6 h, and at end of each INHD session for 4 weeks and to determine extracorporeal dialysis circuit clotting and bleeding events after switching from unfractionated heparin to tinzaparin, using a standard protocol of tinzaparin delivery at the initiation and midpoint of HD. Results: All 16 patients in The Ottawa Hospital INHD program were converted to tinzaparin and followed for 177 INHD sessions. Mean antifactor Xa level at 2 h of HD was 0.41 ± 0.21 (SD) IU/mL, at 4 h (mid-HD) 0.19 ± 0.17 IU/mL, at 6 h 0.44 ± 0.21 IU/mL, and at dialysis end 0.26 ± 0.14 IU/mL. Antifactor Xa levels were undetectable at the start of INHD, suggesting no tinzaparin accumulation. Five patients required an increase in tinzaparin due to extracorporeal dialysis circuit clotting. There were no bleeding events. One patient required a switch to fondaparinux due to an adverse reaction. Conclusion: Tinzaparin was safe and efficacious for most INHD patients without accumulation or bleeding. The conversion from unfractionated heparin to tinzaparin required an increased tinzaparin dose for 31% of INHD patients.