CATEGORY :
Electrolyte .

MECHANISM OF ACTIONS :
Dialysis is solution of electrolytes formulated in concentrations similar to those of extracellular fluid or plasma . It always contains sodium and chloride and bicarbonate or a bicarbonate precursor . In addition , it often contains calcium and magnesium , and rarely potassium . Glucose may be added as an osmotic agent . These solution allows the removal of water and metabolites and the replacement of electrolytes .
In Haemodialysis , the exchange of ions between the solution and the patient`s blood is made across a semi-permeable membrane , primarily by diffusion . Excess fluid is removed by ultrafiltration achieved by a pressure gradient . Membranes are either derived from cellulose ( e.g.cuprophane ) or are synthetic . Bicarbonate rather than a bicarbonate precursor is increasingly preferred as the bicarbonate source in Haemodialysis since the problems of precipitation of calcium and magnesium have been overcome by changes in dialysis technique .
Acetate is still used in some dialysers , but is thought to have vasodilatory and cardiodepressant actions , and may not be converted to bicarbonate fast enough for high – flux Haemodialysis or in patients with liver disease . Haemodialysis solutions are provided in a sterile concentrated form for dilution with water before use ; this water need not be sterile .

INDICATIONS :
Dialysis procedures is used as part of renal replacement therapy in renal failure and electrolyte disturbance to correct electrolyte imbalance , corrects fluid over load , and removes metabolites . It also has a limited role in the treatment of overdosage and poisoning .

DRUG INTERACTIONS :
The effects of dialysis procedure on drug concentrations in the body can be complex . Because of the differences between the dialysis techniques , more drug may be removed by one technique than another , In general , drugs of low molecular weight , high water solubility , low volume of distribution , low protein binding , and high renal clearance are most extensively removed by dialysis . For example , aminoglycosides are extensively removed by dialysis procedures , and extra doses may be needed to replace losses , usually guided by serum – drug concentrations .
Specific drug dosage adjustments for dialysis procedures may be employed where these are known . For drugs where the effect of dialysis is unknown , it is usual to give maintenance doses after dialysis . The ability of dialysis to remove some drugs has been used in the treatment of over dosage .
Dialysis – induced changes in fluids and electrolytes have the potential to alter the effects of some drugs . For example , hypokalaemia predisposes to digoxin toxicity .

PRECAUTIONS :
Haemodialysis should be used with caution in patients with unstable cardiovascular disease or active bleeding . During Haemodialysis , Heparin or Epoprostenol are required to prevent clotting of the blood in the extracorporeal circuit . Dialysis solutions should be warmed to body temperature with dry heat because wet heat carries a risk of microbial contamination .

ADVERSE EFFECTS :
Adverse effects occurring during Haemodialysis include nausea , vomiting , hypotension , muscle cramps , and air embolus . Effects related to vascular access include infection , thrombosis , and Haemorrhage . Long – term complications in dialysed patients , some of which may related to renal failure itself , include Haemodialysis – related amyloidosis , acquired cystic kidney disease , and accelerated atherosclerosis . Dialysis dementia is a special hazard of aluminium overload .
Haemodialysis-induced cramp : Muscle cramps commonly occur during haemodialysis procedures , and are often associated with hypotensions as a result of inappropriate volume removal .
Hypersensitivity : The use of Ethylene oxide for the disinfection of dialysis equipment has been associated with severe , sometimes fatal , anaphylactic reactions .
Infections : Patients undergoing Haemodialysis are at risk of infections from microbial contamination of dialysis fluid , and from inadequate care of vascular access sites .