Page 1839 - Saunders Comprehensive Review For NCLEX-RN

to pass through, such as urea, creatinine, uric acid,
and water molecules.

3. Proteins, bacteria, and some blood cells are too

large to pass through the membrane.
4. The client’s blood flows into the dialyzer; the
movement of substances occurs from the blood to the
dialysate by the principles of osmosis, diffusion, and
ultrafiltration.
5. Osmosis is the movement of fluids across a
semipermeable membrane from an area of lower
concentration of particles to an area of higher
concentration of particles.
6. Diffusion is the movement of particles from an area of
higher concentration to one of lower concentration.
7. Ultrafiltration is the movement of fluid across a
semipermeable membrane as a result of an artificially
created pressure gradient.
D. Dialysate bath
1. A dialysate bath is composed of water and major
electrolytes.

2. The dialysate need not be sterile because

bacteria and viruses are too large to pass through the
pores of the semipermeable membrane; however, the
dialysate must meet specific standards, and water is
treated to ensure a safe water supply.

E. Interventions

1. Monitor vital signs before, during, and after dialysis;
the client’s temperature may elevate because of slight
warming of the blood from the dialysis machine
(notify the PHCP about excessive temperature
elevations because this could indicate sepsis,
requiring blood cultures to be collected).
2. Monitor laboratory values, specifically the BUN,
creatinine, and complete blood cell counts before,
during, and after dialysis.
3. Assess the client for fluid overload before dialysis and
fluid volume deficit following dialysis.
4. Weigh the client before and after dialysis to determine
fluid loss. Note that the client will not urinate or will
urinate small amounts (may be less than 30 mL/hr).
5. Assess the patency of the blood access device before,
during, and after dialysis.
6. Monitor for bleeding; heparin is added to the dialysis
bath to prevent clots from forming in the dialyzer or

1839