Dialysis types and principles @nurses outlook

INTRODUCTION -:


When kidney failure can no longer be managed conservatively ,dialysis is required to sustain life .Dialysis is  the movement of fluid and molecules across a semi permeable   membrane from one compartment to another .dialysis is  the passage of molecules through a semi-permeable membrane into a special solution called dialysate solution .dialysis operates like the kidney .small molecules like urea , creatinine , and electrolytes pass out of  blood ,across a membrane ,and into a solution

DEFINITION-:

Dialysis is a process used to remove fluid and uraemic waste products from the body when the kidneys are unable to do so.

It may also be used in treating patients with intractable (not responsive to treatment), oedema hepatic coma,hyperkalemia,hypercalcemia,hypertension,uraemia.

METHODS OF DIALYSIS-:

There are mainly 2 methods of dialysis

  • Peritoneal dialysis(PD)

  • Hemodialysis(HD)



TYPES OF DIALYSIS-:

  1. Acute dialysis

  2. Chronic dialysis

Acute dialysisit is indicated when there is high and rising level of serum potassium, fluid overload, or impending pulmonary oedema, increasing acidosis, pericarditis, and severe confusion. It may also be used to remove certain medications or medication overdose From the blood.

Chronic  or  maintainence dialysis

It is indicated in chronic renal failure ,known as end stage renal disease (ESRD),in the following instance; the occurrence  of uraemic sign & symptoms affecting all body system (nausea ,vomiting ,severe anorexia, increasing lethargy mental confusion),hyperkalemia ,fluid overload not responsive to diuretics and fluid restriction and a general lack of well being.



GOAL OF DIALYSIS-:

  •  Remove the end products of protein metabolism from the blood.

  • Maintain safe concentrations of serum electrolytes.

  • Correct acidosis & replenish the body’s bicarbonate buffer system.

  • Remove excess fluid from blood

Dialysis enables many patients to maintain or regain self-esteem and to be productive members of society .however initial positive feelings about dialysis sometimes turn to depression as the reality of “being tied to a machine “is recognized.



GENERAL PRINCIPLES OF DIALYSIS-:

Solutes and water moves across the semi permeable membrane from the blood to the dialysate or from the dialysate to the blood in accordance with concentration gradients.



Three principles involve in the dialysis-:

  1. Diffusion

  2. Osmosis

  3. Ultra filtration



Diffusion - The toxins and wastes in the blood are removed by diffusion.

Diffusion is the movement of solutes from an area of greater concentration to an area of lesser concentration in the dialysate.



Dialysate

It is a solution composed of all the important electrolytes in their ideal extracellular concentrations.the electrolyte level in the blood can be brought under control by properly adjusting the dialysate bath.

Osmosis –

excessive water is removed from the blood by osmosis in which water moves from an area of higher solutes concentration (blood)to lower solute concentration (the dialysate bath).

Ultrafiltration –

      It is defined as water moving under high pressure to an area of lower pressure .this process is much more efficient at water removal than is osmosis.

Ultra filtration is accomplished by applying negative pressure or a suctioning force to the dialysis membrane .because patients with renal disease usually cannot excrete water, this force is necessary to remove fluid to achieve fluid balance.

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