Question

Principles of dialysis diffusion convection osmosis ultrafiltration

Answer 1

Explanation:

Chronic renal failure is the final common pathway of a number

of kidney diseases. The choices for a patient who reaches the

point where renal function is insufficient to sustain life are

1) chronic dialysis treatments (either hemodialysis or peritoneal dialysis),

2) renal transplantation, or 3) death. With renal failure of any cause,

there are many physiologic derangements. Homeostasis of water and

minerals (sodium, potassium, chloride, calcium, phosphorus, magnesium, sulfate), and excretion of the daily metabolic load of fixed

hydrogen ions is no longer possible. Toxic end-products of nitrogen

metabolism (urea, creatinine, uric acid, among others) accumulate in

blood and tissue. Finally, the kidneys are no longer able to function as

endocrine organs in the production of erythropoietin and 1,25-dihydroxycholecalciferol (calcitriol).

Dialysis procedures remove nitrogenous end-products of catabolism and begin the correction of the salt, water, and acid-base derangements associated with renal failure. Dialysis is an imperfect treatment

for the myriad abnormalities that occur in renal failure, as it does not

correct the endocrine functions of the kidney.

Indications for starting dialysis for chronic renal failure are empiric

and vary among physicians. Some begin dialysis when residual glomerular

filtration rate (GFR) falls below 10 mL/min /1.73 m2 body surface

area (15 mL/min/1.73 m2 in diabetics.) Others institute treatment

when the patient loses the stamina to sustain normal daily work and

activity. Most agree that, in the face of symptoms (nausea, vomiting,

anorexia, fatigability, diminished sensorium) and signs (pericardial

friction rub, refractory pulmonary edema, metabolic acidosis, foot or

wrist drop, asterixis) of uremia, dialysis treatments are urgently indicated.