Dialysate solution

Sodium hydrogen zirconium phosphate [34370-53-17 is an ion-exchange material used in portable kidney dialysis systems which regenerate and reckculate the dialysate solution. The solution picks up urea during the dialysis. The urea reacts with urease to form ammonia, which is absorbed by the sodium hydrogen zirconium phosphate. 

Dialysis involves the removal of metabolic waste products by diffusion and ultrafiltration from the bloodstream across a semipermeable membrane into an external dialysate solution. 

As will be seen later (Section V.l), meaningful molecular weights in multicomponent systems can be determined, if the specific refractive index increment appertains to conditions of constant chemical potential of low molecular weight solvents (instead of at constant composition). Practically, this can be realised by dialysing the solution against the mixed solvent and then measuring the specific refractive index increment of the dialysed solution. The theory and practice have been reviewed4-14-1S> 72>. 

A dialysate solution of a composition appropriate to the patient is prepared by diluting with water one of concentrated dialysates of standard compositions that are available commercially. Typical compositions of diluted dialysates are as follows Na 130-140mEql , K 2-2.5 mEql , Ca" 2.5-3.5 mEql , Mg + 1.0-1.5mEql", Cl 100-110 mEql HCOj" 30-35 mEql b glucose 0 or 1-2 gl , osmolarity 270-300 mOsm 1 T Electrolytes are added to the dialysate mainly to prevent electrolytes in the body fluid from moving into the dialysate, and sometimes to control the concentration of some ions such as Na in the body fluid at an appropriate level. 

The dialysate solution is recirculated through the hemodyalyzer system. In hospitals where multiple patients are treated, central dialysate supply systems are normally used. The flow rates of blood and dialysate through a hollow-fiber-type... 

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. 

As an artificial dialyzer is not used in peritoneal dialysis, use of the term artificial kidney might not be appropriate in this case. In peritoneal dialysis,the dialysate solution is infused into the peritoneal cavity of the patient and later discharged. Uremic toxins in the blood are removed as the blood flows through the capillaries in the peritoneum to the dialysate by diffusion. Water is removed by adding glucose to the dialysate, thereby making the osmolarity of dialysate higher than that of the blood. 

In continuous ambulatory peritoneal dialysis (CAP )), approximately 21 of dialysate solution is infused into the patient s peritoneal cavity, and is exchanged with new dialysate about four times each day. The patient need not stay in bed, as with ordinary hemodialysis, but it is difficult to continue CAPD for many years due to the formation of peritoneal adhesions. 

The Association for the Advancement of Medical Instrumentation has issued a standard recommending that water used in the preparation of dialysate solution contain less than 10 g aluminum per liter. The purpose is to limit the unintentional administration of aluminum to dialysis patients whose renal dysfunction and the inefficiency of dialysis equipment to remove aluminum could cause an aluminum buildup to biologically hazardous levels (AAMI 1998). 

Dialysis waste products dialyse out into the washing dialysing solution... 

Haemodialysis usually takes about 4-7 h and the dialysing solutions are changed periodically. Ask in your hospital about the exact procedures used for dialysis, usually organized by the renal unit. You also might ask what stringent safety and health risk precautions the workers must undertake when working in the unit. 

Experimentally, the first step in amino acid analysis, whose origins go back to the work of Stein and Moore in 1948, is hydrolysis of the protein. The protein sample should not contain too much salt, detergent or other additives, and dialysis against a dilute buffer or even water is recommended as a first step. The dialysed solution is then dried in vacuo the quantity needed depends on the sensitivity of the amino acid analyser (typically 1-10 nmol, with older forms of apparatus needing 10- tolOO-fold larger size samples). The dried sample is then subjected to hydrolysis 6 M HQ at 150 °C for 6 h, or 125 °C for 24 h, or 110 °C for 48 h. To exclude oxygen, 0.02 % (v/v) 2-mercaptoethanol and 0.25 % (w/v) phenol are added to the hydrolysis. With the most sensitive amino add analysers currently available, it is possible to analyse protein samples recovered from polyacrylamide gels and blotted onto PVDF-membranes. 

The composition of the hydrosol has not been determined, but it is thought to consist of tun tic acid in combination with water, or possibly with sodium tungstate, since Sabaneeff obtained an amorphous powder, of composition NagO.IiWOg, from the dialysed solution. 

D Fiaese PC, Lamberts LV, Liang L, Boone LP,Van Waeleghem, De Broe ME. Contribution of parenteral and dialysate solutions to the aluminum accumulation in dialysis patients. BloodPurif 990 8 359-362. 

The membrane separates the blood from a dialyzing solution, or dialysate, that is similar to blood plasma in its concentration of needed substances (e.g., electrolytes and amino acids) but contains none of the waste products. Because the concentrations of undesirable substances are thus higher in the blood than in the dialysate, they flow preferentially out of the blood and are washed away. The concentrations of needed substances are the same on both sides of the membrane, so these substances are maintained at the proper concentrations in the blood. The small pore size of the membrane prevents passage of blood cells. However, Na and Cl ions and some small molecules do pass through the membrane. A patient with total kidney failure may require up to four hemodialysis sessions per week, at 3 to 4 hours per session. To help hold down the cost of such treatment, the dialysate solution is later purified by a combination of filtration, distillation, and reverse osmosis and is then reused. 

Hemodialysis consists of the perfusion of blood and a physiologic salt solution on opposite sides of a semipermeable membrane. Multiple substances, such as water, urea, creatinine, uremic toxins, and drugs move from the blood into the dialysate, thus facilitating removal from the blood. Solutes are transported across the membrane by either passive diffusion or ultraflltration. Diffusion is the movement of substances along a concentration gradient, the rate of diffusion depends on the difference between the concentrations of solute in blood and dialysate, solute characteristics, the dialyzer composition, and flow rates (blood and dialysate). Ultraflltration is the movement of water across the membrane due to hydrostatic or osmotic pressure, and is the primary means for removal of excess body water. Convection (expressed as mL of plasma water removed per hour per mm of mercury of pressure within the dialyzer) occurs... 

A dialysate solution of a composition appropriate to the patient is first prepared by diluting with water one of concentrated dialysates of standard compositions that... 

The dialysate solution is recirculated through the hemodialyzer system. In hospitals where multiple patients are treated, central dialysate supply systems are normally used. The flow rates of blood and dialysate through a hollow-fiber-type dialyzer are approximately 200-300 ml min-1 and 500 ml min-1, respectively. The more recently developed hemodialyzers have all been disposable that is, they are presterilized and used only once. Normally, a patient will undergo dialysis for 4—5 h per day, for three days each week. 

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