Hemodialysis Hemofiltration

Hemodialysis, hemofiltration, and hemodiafiltration Apparatus and principles Factors governing drug removal Hemodialysis in poisoning Hemofiltration and hemodiafiltration in poisoning Hemoperfusion ... 

Weiss LG, Danielson BG, Fellstrom B, et al. Aluminum removal with hemodialysis, hemofiltration and charcoal hemoperfusion in uremic patients after desferrioxamine infusion. A comparison of efficiency. Nephron. 1989 51 325-329... 

Padovese P, Gallleni M, Brancaccio D, Pietra R, Fortaner S, Sabbioni E, Minoia C, Markakis K, Berlin A. Trace elements in dialysis fluids and assessment ofthe exposure of patientson regular hemodialysis, hemofiltration and continous ambulatory peritoneal dialysis. Nephron 1992 61 442-448. 

In contrast to hemodialysis, hemofiltration relies on convective transport and thus is more analogous to nephron function. Hydrostatic pressure is used to form about 80 to 100... 

Hemodialysis/hemofiltration alone had sales of over US 2200 million in 1998. Reverse osmosis (RO), ultrafiltration (UF) and microfiltration (MF) together accounted for 1.8 billion dollars in sales in 1998. At that time about US 400 million worth of membranes and modules were sold each year worldwide for use in reverse osmosis. About 50% of the RO market was controlled by Dow/FihnTec and Hydranautics/Nitto. They were followed by DuPont and Osmonics. Membranes are apphed during sea-water desahnation, municipal/ brackish water treatment and in the industrial sectors. The market for RO and nanofiltration is growing at a rate higher than 10%/year. The market for desali-... 

Chronic renal insufficiency is treated by different forms of hemodialysis, hemofiltration, or continuous ambulatory peritoneal dialysis (CAPD). All patients have low HDL levels but show a relative increase in A-I. This condition may be called hyperapoalphalipoproteinemia. 

Membranes have been used in clinics for therapeutic purposes since 1943, when Kolff successfully treated a uremic patient with his rotating dmm membrane dialyzer (Kolff and Berk, 1943). Nowadays, hemodialysis, hemofiltration, hemodiafiltration, therapeutic apheresis, and gas exchange during cardiopulmonary bypass surgery have become clinically established treatments. In the following, feamres and therapeutic objectives of these treatments are briefly presented. 

Fig. 14. Mass transfer across hemodialysis and hemofiltration hoUow-fiber membranes.

CWH, continuous venovenous hemofiltration CWHD, continuous venovenous hemodialysis CVVHDF, continuous venovenous hemodiafil-tration. 

It is critically important to recognize that the treatments of hyperkalemia discussed thus far are transient, temporizing measures. They are intended to provide time to institute definitive therapy aimed at removing excess potassium from the body. Agents that increase potassium excretion from the body include sodium polystyrene sulfonate, loop diuretics, and hemodialysis or hemofiltration (used only in patients with renal failure). Sodium polystyrene sulfonate (Kayexalate , various manufacturers) can be given orally, via NG tube, or as a rectal retention enema and is dosed at 15 to 60 grams in four divided doses per day. 

Hemodialysis machine, 26 814 Hemodialysis potting, 16 17 Hemodialysis prescription, 26 817-818 Hemodynamic chromatography, 6 722 Hemofiltration, 16 20 fibers for, 16 22... 

Metabolism/Excretion - In the first 24 hours, approximately 75% of a dose is excreted in urine by glomerular filtration. Elimination half-life is 4 to 6 hours in adults and 2 to 3 hours in children. About 60% of an intraperitoneal dose administered during peritoneal dialysis is absorbed systemically in 6 hours. Accumulation occurs in renal failure. Serum half-life in anephric patients is approximately 7.5 days. Vancomycin is not significantly removed by hemodialysis or continuous ambulatory peritoneal dialysis, although there have been reports of increased clearance with hemoperfusion and hemofiltration. 

Peritoneal dialysis Supplemental doses of valacyclovir should not be required following chronic ambulatory peritoneal dialysis (CARD) or continuous arteriovenous hemofiltration/hemodialysis (CAVHD). 

Fehrman-Ekhohn I, Lotsander A, Logan K, Dunge D, Odar-Cederlof I, Kallner A. Concentrations of vitamin C, vitamin B12 and folic acid in patients treated with hemodialysis and on-line hemodiafiltration or hemofiltration. Scand J Urol Nephrol 2008 42(1) 74-80. 

Because the drug and the mobilized metals are excreted via the urine, the drug is relatively contraindicated in anuric patients. In such instances, the use of low doses of EDTA in combination with hemodialysis or hemofiltration has been described. Nephrotoxicity from EDTA has been reported, but in most cases can be prevented by maintenance of adequate urine flow, avoidance of excessive doses, and limitation of a treatment course to 5 or fewer consecutive days. EDTA may result in temporary zinc depletion that is of uncertain clinical significance. Analogs of EDTA, the calcium and zinc disodium... 

In the hemofiltration HF (i.e., ultrafiltration see Section 8.3) of blood, using an appropriate membrane, all of the solutes in plasma below a certain molecular weight will pass into the filtrate at the same rate, irrespective of their molecular sizes, as occurs in the human kidney glomeruli. Since its first proposal in 1967 [14], HF has been studied extensively [15-17]. Although a dialysate solution is not used in HF, the correct amount of substitution fluid must be added to the blood of the patient, either before or after filtration, to replace all the necessary blood constituents that are lost in the filtrate. This substitution fluid must be absolutely sterile, as it is mixed with the patient s blood. For these reasons, HF is more expensive to perform than hemodialysis, and so is not generally used to the same extent. 

Peritoneal Dialyis There is no information specific to administration of VALTREX in patients receiving peritoneal dialysis. The effect of chronic ambulatory peritoneal dialysis (CARD) and continuous arteriovenous hemofiltration/dialysis (CAVHD) on acyclovir pharmacokinetics has been studied. The removal of acyclovir after CARD and CAVHD is less pronounced than with hemodialysis, and the pharmacokinetic parameters closely resemble those observed in patients with ESRD not receiving hemodialysis. Therefore, supplemental doses of VALTREX should not be required following CARD or CAVHD. 

A 45-year-old man with mediastinitis and renal and hepatic dysfunction was treated with mediastinal irrigation with povidone iodine (70). He developed toxic plasma iodine concentrations and clinical deterioration hemodialysis and hemofiltration were effective in reducing plasma iodine concentrations. 

The results of hemodialysis in biguanide-induced lactic acidosis are variable. Metformin and buformin are dialy-sable, but phenformin is poorly eliminated. Successful continuous venovenous hemofiltration has been reported (81). 

Among patients with advanced kidney disease (mean creatinine clearance, 26 mL/min), an increase in SCr levels of at least 25% was significantly less common in patients randomly assigned to prophylactic hemofiltration before and after the administration of CM than in those assigned to receive fluid alone (5% vs. 50%, p < 0.001) (75), In-hospital death was also significantly less frequent in the hemofiltration group, However, the SCr level is directly altered by the intervention, and the relationship between the intervention and the reduced mortality rate is unclear. Thus, the role of hemodialysis in patients at high risk for CIN remains uncertain. 

Hemodialysis (383,552,553), sometimes with additional continuous venovenous hemofiltration dialysis (554,555), continues to be described as a successful intervention for lithium poisoning. Peritoneal dialysis is a far less efficient way to clear lithium from the body. One patient treated in this way had permanent neurological abnormalities and another died a third toxic patient who also had diabetic ketoacidosis died after treatment with hydration and insulin (556). On the other hand, a 51-year-old woman who took 50 slow-release lithium carbonate tablets (450 mg) had a serum lithium concentration of 10.6 mmol/1 13 hours later, but no evidence of neurotoxicity or nephrotoxicity. She was treated conservatively with intravenous fluids and recovered fully (557). Acute lithium overdose is often better tolerated than chronic intoxication. 

Two teenagers with neurological toxicity (serum concentrations 5.4 mmol/1 and 4.81 mmol/1) were treated successfully with hemodialysis followed by continuous venovenous hemofiltration, which prevented a post-dialysis rebound in serum lithium concentrations (554). 

Meyer RJ, Flynn JT, Brophy PD, Smoyer WE, Kershaw DB, Custer JR, Bunchman TE. Hemodialysis followed by continuous hemofiltration for treatment of hthium intoxication in children. Am J Kidney Dis 2001 37(5) 1044-7. 

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