Hemodialysis procedures

Renal Effects. The patient described by Letz et al. (1984) (see Section 2.2.3.1) who lived for 64 hours after exposure to toxic levels of 1,2-dibromoethane had acute renal failure as evidenced by severe oliguria 24 hours after exposure and abnormal clinical chemistry values (blood urea nitrogen, creatinine, and serum uric acid). Severe metabolic acidosis was present despite two hemodialysis procedures. 

Sodium chloride (normal saline)- 0.9% Sodium chloride (normal saline), which is isotonic, restores both water and sodium chloride losses. Other indications for parenteral 0.9% saline include Diluting or dissolving drugs for IV, IM, or subcutaneous injection flushing of IV catheters extracellular fluid replacement treatment of metabolic alkalosis in the presence of fluid loss and mild sodium depletion as a priming solution in hemodialysis procedures and to initiate and terminate blood transfusions without hemolyzing red blood cells. 

The most common complications that occur during the hemodialysis procedure include hypotension, cramps, nausea and vomiting, headache, chest pain, hack pain, and fever or chiUs. Table 45-3 hsts these comphcations and the etiology with predisposing factors... 

The number of patients with ESKD who receive chronic hemodialysis has steadily increased since the early 1970s and currently over 260,000 patients receive this life-sustaining therapy. Although many new hemodialyzers have been introduced in the past 20 years and the efficiency of the hemodialysis procedure has been increased, the effect of hemodialysis on drug disposition is rarely re-evaluated after it is initially reported. Thus most of the literature probably represents an underestimation of the impact of hemodialysis on drug disposition. 

Carrying such a miniaturized portable artificial kidney could substantially increase the periods between normal hemodialysis procedures, thus making the patient much less dependent on his residency clinic. 

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). 

In uremia there are present in the serum a variety of known and unknown metabolites that can produce aberrant laboratory results. Significant differences in glucose concentration have been observed in such specimens analyzed by ferricyanide (F2a) or Fe (II)-5-pyridylbenzo-diazepin-2-one reduction methods compared to glucose oxidase procedures (K7a). In a patient with elevated creatinine (15 mg/100 ml) and uric acid (10 mg/100 ml), the glucose value determined by the automated alkaline ferricyanide procedure was overestimated by 20 mg/100 ml (C4). In uremic patients undergoing chronic hemodialysis there is a decrease in transaminase activity. In 11 of 19 such patients, there was... 

Administration - Epoetin alfa may be given either as an IV or subcutaneous injection. In patients on hemodialysis, epoetin alfa usually has been administered as an IV bolus 3 times/week. While the administration is independent of the dialysis procedure, epoetin alfa may be administered into the venous line at the end of the dialysis procedure to obviate the need for additional venous access. In adult patients with CRF not on dialysis, epoetin alfa may be given either as an IV or subcutaneous injection. 

After appropriate diagnostic and decontamination procedures and administration of antidotes, it is important to consider whether measures for enhancing elimination, such as hemodialysis or urinary alkalinization, can improve the clinical outcome. Table 58-3 lists intoxications for which dialysis may be beneficial. 

Based on the animal data, the most consistent effect of exposure to DEHP is the increase in the concentration of liver peroxisomes. This effect occurs to varying degrees in all species that have been evaluated. However, evidence for an effect of DEHP exposure on human liver peroxisomes is weak. Limited data regarding biopsies from human livers, under circumstances in which DEHP was present in the hemodialysis equipment, did not lead to meaningful conclusions (Ganning et al. 1984, 1987). Therefore, a liver biopsy with subsequent histopathological examination of the cells would seldom if ever be justified as a test for the long-term effects of DEHP exposure due to the difficulties associated with this procedure. 

Plasmapheresis typically employs a membrane module of similar configuration as a high-flux hemodialyzer. Alternatively, a rotating membrane separation element is used in which the tendency of the blood cells to deposit on the membrane surface is counteracted with hydrodynamic lift forces created by the rotation. The membrane element and the associated plasmapheresis circuitry are shown in Fig. 49. Worldwide, about 6 million plasmapheresis procedures are performed annually using this system, making this one of the largest biomedical membrane applications after hemodialysis. 

Hemoperfusion differs from hemodialysis in that the blood is passed over a resin or charcoal column. The drug becomes bound to the column and the clean blood returned to the body. Hemoperfusion units have adsorptive surface areas of several thousand square meters while hemodialysis devices have an effective dialysis surface limited to several square meters. Obviously, relatively sophisticated technology is required for these procedures and there is the need to prevent clotting in the circuit, which can produce complications. 

This patient required hemodialysis for ALPE. Delayed CT and a bone scan with MDP in the recovery phase showed patchy lesions (these imaging procedures were performed in conjunction with another patient with myoglobin uric acute renal failure due to a malignant syndrome). On July 19, 1999, the patient fell into the water while fishing in a mountain stream, and was carried about 100 m in a few minutes while struggling all the time. As a precaution, he was admitted to a local clinic overnight. There were no abnormal laboratory data. However, at 0300 hours on July 21, he attended the Emergency Outpatient Unit of our hospital with severe bilateral loin... 

Finally, there are significant hemodynamic changes during hemodialysis that not only may affect the extent of drug removal by this procedure but also may have an important impact on patient response. 

Complications of hemoperfusion include platelet and leukocyte depletion, hypocalcemia, and a mild reduction in body temperature (50). In many cases, these complications are outweighed by the fact that intoxicants are removed more rapidly by hemoperfusion than by hemodialysis. However, an additional consideration is that hemoperfusion clearance tends to decline during therapy as column efficiency declines, presumably reflecting saturation of adsorbent sites (53). In addition, intercompartmen-tal clearance from skeletal muscle and other slowly equilibrating tissues can limit the extent of drug removal by hemoperfusion and result in a rebound of blood levels and possible toxicity at the conclusion of this procedure (54). In some instances, alternative therapies have been developed that are even more efficient than hemoperfusion. For example. 

A 49-year-old with severe lithium toxicity was treated successfully with continuous veno-venous hemodiafU-tration the serum hthium concentration feU from 3.0 to 0.93 mmol/1 after 7 hours and there was no rebound increase after the end of the procedure (60). The maximum lithium clearance was 28 ml/minute which is considerably lower than usually attained with hemodialysis. 

A 25-year-old white woman took an unknown amount of valproic acid, became comatose, and developed hjrpotension and lactic acidosis. Her valproic acid concentrations rose to over 8400 pmol/l. High-flux hemodialysis was performed for 4 hours the calculated half-hfe during the procedure was 2.7 hours, compared with a posthemodialysis value of 23 hours, suggesting that high-flux hemodialysis had increased the clearance rate of valproic acid. Her hemodynamic status and mental function improved in conjunction with the acute reduction in valproic acid concentrations. 

In hemodialysis the dialysis fluids are prepared from the tap water which may contain considerable amounts of trace metals. In the absence of adequate water treatment procedures it must be considered the main source of trace metal dialysate contamination. Some domestic tap water contains aluminum in high concentrations either naturally or as a result of the addition of the element as a flocculant to the water basins, a procedure which is part of the water purification process and has led to an acute, fatal intoxication of a considerable number of patients in a Portuguese dialysis center (see also below) [17,18]. Worth noting is that concentrations of particular elements in tap water may vary seasonally, e.g. silicon, or even on a day-to-day... 

Hemodialysis, especially on a daily basis is an effective freatinenf for sfar fruif intoxication in the majority of cases, if sfarted earher, according to the literature. In severe cases, continuous methods of replacement may provide a superior initial procedure. In those severe cases that do not respond to these methods, hemoperfusion could be an effective and fast method of treafmenf. Peritoneal dialysis is useless as a treatment, especially when consciousness disorders ensue. 

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