Page 141 - Critical Care Notes

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Treatment of Renal Disorders
Renal Replacement Therapy
Renal replacement therapy (RRT) is a general term used to describe the various
substitution treatments available for severe, acute, and end-stage chronic renal
failure (ESCRF), including dialysis (hemodialysis and peritoneal dialysis),
hemofiltration, and renal transplant. Peritoneal dialysis is generally not recom-
mended in critically ill patients. Research has shown that CRRT and hemodialy-
sis improve patient outcomes better than peritoneal dialysis in this population.
Hemodialysis
Hemodialysis is one of several RRTs used in the treatment of renal failure to
remove excess fluids and waste products → restores chemical and electrolyte
imbalances.
Pathophysiology
Hemodialysis involves passing the patient’s blood through an artificial semiper-
meable membrane to perform filtering and excretion functions that the kidney
can no longer do effectively.
Procedure
Dialysis works by using passive transfer of toxins by diffusion (movement of
molecules from an area of higher concentration to an area of lower concentra-
tion). Blood and dialysate (dialyzing solution) containing electrolytes and H 2 O
(closely resembling plasma) flow in opposite directions through the semiper-
meable membrane. The patient’s blood contains excess H 2 O and excess elec-
trolyte and metabolic waste. During dialysis, the waste products and excess
H 2 O move from blood → dialysate because of the differences in concentrations.
Electrolytes can move in or out of blood or dialysate. This circulating pattern
takes place over a preset length of time, generally 3–4 hr.
Components
The components of the hemodialysis system include:
■ Dialyzer
■ Dialysate
■ Vascular access: subclavian vein, arteriovenous fistula or graft, femoral vein
■ Hemodialysis machine
Heparin is used to prevent blood clots from forming in the dialyzer or in the
blood tubing. The heparin dose is adjusted to the patient’s needs.
Hemodialysis Nursing Care
■ Obtain baseline VS and Spo 2 via pulse oximetry.
■ Obtain baseline weight. Assess for edema and JVD.

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