Dialysis is a process used to remove waste and excess water from the blood, and it’s used mainly to provide an artificial replacement for lost kidney function in patients with renal failure. Dialysis may be used for those with an acute disturbance in kidney function or progressive but chronically worsening kidney function. Dialysis, however, does not correct the compromised endocrine functions of the kidney. Its treatments only replace some of these functions through diffusion (waste removal) and ultrafiltration (fluid removal).
Principle
Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Diffusion is a property of substances in water; substances in water tend to move …show more content…
Haemodialysis
Haemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer which contains a semipermeable membrane.
Before dialysis an artery and a vein is joined internally (fistula) or by a fiber (graft) to develop the required pressure to draw the blood from the patient. Then dialysis is carried out.
The blood flows in one direction and the dialysate flows in the opposite. The counter-current flow of the blood and the dialysate maximizes the concentration gradient of solutes between the blood and dialysate, which helps to remove more urea and creatinine from the blood. Constant replacement of the dialysate ensures that the concentration of undesired solutes is kept low on this side if the membrane. This dialysis solution has levels of minerals like potassium and calcium that are similar to their natural concentration in healthy blood.
For another solute, bicarbonate, dialysis solution level is set at a slightly higher level than in normal blood, to encourage diffusion of bicarbonate into the blood, to act as a pH buffer to neutralize the metabolic acidosis that is often present in these patients. The levels of the components of dialysate are typically prescribed by a nephrologist according to the needs of the individual
Principle
Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Diffusion is a property of substances in water; substances in water tend to move …show more content…
Haemodialysis
Haemodialysis removes wastes and water by circulating blood outside the body through an external filter, called a dialyzer which contains a semipermeable membrane.
Before dialysis an artery and a vein is joined internally (fistula) or by a fiber (graft) to develop the required pressure to draw the blood from the patient. Then dialysis is carried out.
The blood flows in one direction and the dialysate flows in the opposite. The counter-current flow of the blood and the dialysate maximizes the concentration gradient of solutes between the blood and dialysate, which helps to remove more urea and creatinine from the blood. Constant replacement of the dialysate ensures that the concentration of undesired solutes is kept low on this side if the membrane. This dialysis solution has levels of minerals like potassium and calcium that are similar to their natural concentration in healthy blood.
For another solute, bicarbonate, dialysis solution level is set at a slightly higher level than in normal blood, to encourage diffusion of bicarbonate into the blood, to act as a pH buffer to neutralize the metabolic acidosis that is often present in these patients. The levels of the components of dialysate are typically prescribed by a nephrologist according to the needs of the individual