Hemodialysis heparins

Even though intermittent heparinization is required, hemostasis parameters are better corrected with hemodialysis than peritoneal dialysis. 

Clinical chemistry, particularly the determination of the biologically relevant electrolytes in physiological fluids, remains the key area of ISEs application [15], as billions of routine measurements with ISEs are performed each year all over the world [16], The concentration ranges for the most important physiological ions detectable in blood fluids with polymeric ISEs are shown in Table 4.1. Sensors for pH and for ionized calcium, potassium and sodium are approved by the International Federation of Clinical Chemistry (IFCC) and implemented into commercially available clinical analyzers [17], Moreover, magnesium, lithium, and chloride ions are also widely detected by corresponding ISEs in blood liquids, urine, hemodialysis solutions, and elsewhere. Sensors for the determination of physiologically relevant polyions (heparin and protamine), dissolved carbon dioxide, phosphates, and other blood analytes, intensively studied over the years, are on their way to replace less reliable and/or awkward analytical procedures for blood analysis (see below). 

It is believed that heparin acts by neutralizing a number of active blood coagulation factors, thus disrupting the transformation of prothrombin into thrombin. Heparin is used to prevent thrombo-formation in myocardial infarctions, thrombosis, and embolism, for maintaining liquid conditions in the blood in artificial blood drcnlation and hemodialysis. Synonyms of this drug are arteven, hepalen, leparan, Uquemin, panheprin, vetren, and many others. 

HCG human chorionic gonadotropin HCL hairy cell leukemia Hct hematocrit HCTZ hydrochlorothiazide HD hemodialysis HDAC histone deacetylase Hep hepatitis hepatotox hepatotoxicity HER2 type of cancer gene HF heart failure HFA designation for type of inhalation device Hgb hemoglobin HIT/HITTS heparin-mduced thrombocytopenia... 

Epoprostenol is the natural occurring prostacyclin which is formed in vascular endothelial cells. It increases cyclic AMP in the thrombocyte and is a strong platelet aggregation inhibitor. It is used to prevent thrombotic complications during hemodialysis when heparin is contraindicated. As its duration of action is no longer than 30 minutes it has to be given as an intravenous infusion. 

Zusman RM, Rubin RH, Cato AE, Cocchetto DM, Crow JW, Tolkoff-Rubin N. Hemodialysis using prostacyclin instead of heparin as the sole antithrombotic agent. N Engl J Med 1981 304(16) 934-9. 

Heparin-induced hypoaldosteronism is well documented, both in patients treated with standard heparin, even at low doses, and in patients treated with low molecular weight heparin (477,478). The most important mechanism of aldosterone inhibition appears to be a reduction in both the number and affinity of angiotensin II receptors in the zona glomerulosa (477). A direct effect of heparin on aldosterone synthesis, with inhibition of conversion of corticosterone to 18-hydroxycorticosterone, has also been suggested. This effect is believed to be responsible for the hyperkalemia that can occur in heparin-treated patients with impaired renal function and particularly in patients on chronic hemodialysis (479), or with diabetes mellitus, or who are taking other potentially hyperkalemic drugs. 

Hottelart C, Achard JM, Moriniere P, Zoghbi F, Dieval J, Fournier A. Heparin-induced hyperkalemia in chronic hemodialysis patients comparison of low molecular weight and unfractionated heparin. Artif Organs... 

I 5 Matsuo T, Matsuo M, Kario K, et al, Characteristics of heparin-induced platelet aggregates in chronic hemodialysis with long-term heparin use. Haemostasis 2000 30 249-257. 

An interaction of heparin with digitoxin has been described and ascribed to altered protein binding, secondary to changes in fatty acid concentrations, but the clinical relevance, for example in patients undergoing hemodialysis, is unclear (207). 

Vascular access thrombosis has been reported in up to 26% of patients treated with epoetin alfa (3,34,38). Most of the failures occurred in poljdetrafluoroethylene grafts. There was no comparison with patients not treated with epoetin. It has been suggested that the increased risk of extracorporeal circuit clotting and the higher heparin requirements during hemodialysis may not be due to a hypercoagulable state, but rather to an increase in erythrocyte mass and consequently in whole blood viscosity (66). 

High doses of epoetin in children undergoing long-term hemodialysis is associated with increased heparin requirements during hemodialysis, suggesting that careful monitoring of thrombotic events, especially in small children who need catheters for hemodialysis access, is warranted (114). 

Pseudo-hypocalcemia can occur in hemodialysis patients, particularly in those who have chylomicronemia before administration of heparin (120). This spurious hjrpocalce-mia is thought to result from lipolytic activity in vitro, sufficient to produce calcium soaps of fatty acid. This can be detected and eliminated by the analysis of blood samples immediately after venepuncture. During hemodialysis, there is a significant fall in plasma ionized calcium after intravenous administration of heparin (an average reduction of 0.03 mmol/1 after 10 000 lU) (121). 

Yamamoto S, Koide M, Matsuo M, Suzuki S, Ohtaka M, Saika S, Matsuo T. Heparin-induced thrombocytopenia in hemodialysis patients. Am J Kidney Dis 1996 28(l) 82-5. 

Godolphin W, Cameron EC, FrohUch J, Price JD. Spurious hypocalcemia in hemodialysis patients after heparinization. In-vitro formation of calcium soaps. Am J Qrn Pathol 1979 71(2) 215-18. 

Heparin is used as an anticoagulant for prophylaxis and treatment of various thromboembolic disease processes. It is used to maintain relatively anticoagulated states in patients on extracorporeal circulation or hemodialysis and to help maintain patency of indwelling vascular catheters. 

Pruritis may be exacerbated during hemodialysis. Sometimes it is ameliorated by using a different dialyzer, changing from porcine to bovine heparin, the oral administration of an antihistaminic agent, or intravenous administration of lido-caine (B22),... 

Akzo). Exhibits antithrombotic activity comparable to standard heparin but with diminished hemorrhagic effects D. G. Meuleman et aL, Thromb. Res. 27, 353 (1982) H. ten Cate et al, ibid. 38, 211 (1985). Preliminary pharmacokinetics and tissue distribution in humans ]. D. Brad brook er al, Brit. J, Clin. Pharmacol 23, 667 (1987). Clinical evaluation during hemodialysis C. P. Henny el al, Lancet 1, 890... 

The excellent sorption capacity of the hypercrosslinked mesoporous poly-DVB with respect to selective removal of P2M from its mixtures with albumin and other semm proteins, combined with superior hemocompat-ibility of the beads surface modified with poly(N-vinyl)pyrrolidone, justified the manufacturing of an experimental batch of the material for initial clinical studies. The polymer was named BetaSorb (RenalTech International, USA) and was used in 300 mL cylindrical polysrdfone devices that were steam-sterilized and filled with normal saline containing 1000 lU heparin. The device was placed in line with the dialysis circuit, upstream of the dialyzer, in order to not affect the pressure drop across the dialyzer membrane. The blood flow was maintained at the customary value of 400 mL/ min, again the optimal flow rate for the dialyzer. The complete setup of the combined hemoperfusion-hemodialysis treatment [361] is displayed in Fig. 15.2. 

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