Hemodialysis monitoring

Figure 12 shows a possible set-up for hemodialysis monitoring. Patients blood is pumped through a dialysis cell, and low molecular weight substances including urea are removed by a semipermeable membrane (cut off 10 kD) and dialysis buffer. The urea enriched dialysate passes through an injection valve and enters a waste container. Due to switching the valve, a defined sample volume is pumped to the ET. Here, enzymatic conversion takes place via immobilized urease and provides information about the current urea concentration. Thus, the hemodialysis effect is automatically monitored via urea analysis and makes an individual treatment possible. 

An amperometric urea sensor based on the pH dependence of the anodic oxidation of hydrazine (Kirstein, 1987) has been utilized in the Glukometer GKM 02 for hemodialysis monitoring. For urea concentration in dialyzate the following correlation was obtained with the Ber-thelot method ... 

Scanferla, E., Landini, S., Fracasso, A., Morachiello, P, Righetto, F.,Toffoletto, P.P. and Bazzato, G. (1990) On-Line Bioelectric Impedance During Hemodialysis Monitoring of Body Fluids and Cell Membrane Status. Nephrol. Dial. Transplant Suppl. 1,167-170. 

The nurse monitors the patient for signs and symptoms of acute salicylate toxicity or salicylism (see Display 17-1). Initial treatment includes induction of emesis or gastric lavage to remove any unabsorbed drug from the stomach. Activated charcoal diminishes salicylate absorption if given within 2 hours of ingestion. Further therapy is supportive (reduce hyperthermia and treat severe convulsions with diazepam). Hemodialysis is effective in removing Hie salicylate but is used only in patients with severe salicylism. 

Treatment of barbiturate toxicity is mainly supportive (ie, maintaining a patent airway, oxygen administration, monitoring vital signs and fluid balance). The patient may require treatment for shock, respiratory assistance, administration of activated charcoal, and in severe cases of toxicity, hemodialysis. 

All patients with major patterns are monitored for rhabdomyolysis and renal failure. An early sign of rhabdomyolysis is an elevated serum uric acid, associated with an increase in serum CK. Within 8 to 12 hours, the serum tests are repeated. If the uric acid falls and the CK rises, rhabdomyolysis is likely. Renal function tests may also be increased at this time. When the diagnosis of rhabdomyolysis is made, the patient is treated with 40 mg furose-mide IV once, and IV fluids. Urine myoglobin concentrations are obtained. If the patient develops renal failure, hemodialysis or peritoneal dialysis may be necessary. In all cases, multiple drug intoxication, trauma, and rhabdomyolysis are ruled out or treated. All patients are kept under observation until they are asymptomatic. 

In-center hemodialysis enables closer monitoring of the patient. 

D/C all antiretrovirals symptomatic support with fluids some patients require IV bicarbonate, hemodialysis, parenteral nutrition, or mechanical ventilation once syndrome resolves, consider using NRTIs with 4- mitochondrial toxicity (ABC, TDF, 3TC, or FTC) monitor lactate after restarting NRTIs some clinicians use NRTI-sparing regimens. 

Exercise extreme caution in the use of sotalol in patients with renal failure undergoing hemodialysis. The half-life of sotalol is prolonged (up to 69 hours) in anuric patients. However, sotalol can be partly removed by dialysis with subsequent partial rebound in concentrations when dialysis is completed. Safety (heart rate, QT interval) and efficacy (arrhythmia control) must be closely monitored. 

Renal Impairment-Adjust dosage according to degree of renal impairment and carefully monitor patients. Because only a minimal amount of clonidine is removed during hemodialysis, there is no need to give supplemental clonidine following dialysis. 

Renal function impairment- In patients with end-stage renal disease requiring hemodialysis, dose reduction to 135 meg peginterferon alfa-2a is recommended. Closely monitor for signs and symptoms of interferon toxicity. Do not use ribavirin in patients with creatinine clearance less than 50 mL/min. 

Figure 18.2 (a) Schematic of extracorporeal circuit in hemodialysis and hemodiafiltration. Substitution fluid is added only in the case of large UFflowrate, that is, in HDF. (b) Fresenius monitor 5008 used for HD or HDF. 

DEHP exposure of humans might result from intravenous administration of blood that has been stored in plastic containers, or through hemodialysis. Under situations such as these, in which DEHP is introduced directly into the blood, it is possible to evaluate exposure by measuring blood DEHP concentrations. DEHP metabolites, MEHP and phthalic acid, are also measured in the blood to determine exposure from medical products or devices (Barry et al. 1989 Sjoberg and Bondesson 1985). If the total amount of phthalate is to be monitored, the phthalate esters are first de-esterified (Liss et al. 1985). Techniques that measure total phthalic acid are not specific for DEHP exposure since other alkyl phthalic acid esters that are used as plasticizers will also produce phthalic acid after de-esterification. 

In hemodialysis, blood from the patient flows on one side of a membrane and a specially prepared dialysis solution is fed to the other side. Waste material in the blood such as urea, excess acids, and electrolytes diffuse into the dialysate the blood is then returned to the patient, as shown in Fig. 48. A patient typically undergoes dialysis three times per week in sessions lasting several hours each. Modern dialysis systems combine sophisticated monitoring and control functions to ensure safe operation. Regenerated cellulose was the first material used in hemodialysis membranes because of its biocompatibility and low cost it remains the most popular choice. Subsequently, high-permeability dialysis membranes derived from cellulose esters, modified polysulfone, or polyacrylonitrile copolymers have also gained wide acceptance because of the shorter sessions they make possible. 

Phenobarbitone Sodium Phenobarbitone sodium decomposes in aqueous solutions. Barbiturate poisoning may be treated with stomach wash and administration of activated charcoal. Monitoring respiratory, cardiovascular, and renal functions, hemodialysis, charcoal administration, forced diuresis, symptomatic and supportive therapy, and peritoneal dialysis may be performed. 

The treatment for VHP infection is mainly supportive, including intravenous fluids and electrolyte replacement. Hemodialysis, invasive monitoring, and vasopressor therapy may also be needed. Care should be taken... 

The use of ascorbic acid in patients with renal insufficiency should be carefully monitored to avoid accelerated development of secondary oxalosis hyperoxalemia has been reported to be aggravated by ascorbic acid supplementation in regular hemodialysis patients (38). The pharmacological mechanism has been clarified in animal experiments (SEDA-15, 414) (39). 

In patients undergoing chronic hemodialysis, the safety profile did not differ from that reported in other populations, except for some rare cases of hypotension during hemodialysis. Hemodialysis does not affect the kinetics of candesartan. Because of the variability of oral clearance and the pronounced influence of hemodialysis-induced volume contraction on the hemodynamic effects of candesartan, careful monitoring is recommended (2). 

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). 

Hemodialysis (HD) is the method of extracorporeal drug removal most commonly used in the treatment of poisoning [1]. The apparatus consists of a blood circuit, an electronic and mechanical device (with pumps and pressure monitors), a dialyzer cartridge (containing hollow permeable fibers), and a dialysate circuit (of purified water with added electrolytes). In practice, a double-lumen catheter is first placed in a central vein. 

Fluorescence detection at 284/310 nm (extinction/ emission wavelengths) leads to a detection limit of 1.3 mmol/L (0.14 mg/mL for / -cresol). Identification of phenol and /7-cresol may be confirmed by liquid chroma- tography/mass spectrometry. Because HPLC methods require only simple extraction, e.g., by ethyl acetate, and do not require further steps such as derivatization, they j are simple and rapid compared with gas chromatography or gas chromatography/mass spectrometry. Such methods I are useful for monitoring serum phenols in dialyzed patients as an index of hemodialysis adequacy. How- ever, the separation of the three isomers of cresol can only be performed by adding 3-cyclodextrin to the c liquid phase. q... 

Dilution may be accomplished with water or with demulcent fluids such as milk. Gastric lavage is indicated in certain circumstances. Hemodialysis and charcoal hemoperfusion may be employed in the event of renal failure. Fluid balance should be monitored and supportive measures taken as indicated. 

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