Peritoneal Dialysis

Question 1

Explain the basic principles o f haem odialysis.

Answer 1

Blood and dialysis fluid flow either side of a semiperm eable membrane, molecules diffuse down their concen tration gradients, plasma biochemistry changes to becom e m ore like the dialysis fluid.

Question 2

Complications of dialysis

Answer 2

B acterial peritonitis, local infection at cath eter site, constipation,
failure, sclerosing peritonitis.

Question 3

Most common cause of peritonitis in dialysis

Answer 3

coagulase-negative staphylococci such as Staphylococcus epidermidis is the most common cause

Question 4

how to treat peritonitis in dialysis

Answer 4

the BNF recommends vancomycin (or teicoplanin) + ceftazidime added to dialysis fluid OR vancomycin added to dialysis fluid + ciprofloxacin by mouth

Question 5

haemodialysis vs peritoneal dialysis

Answer 5

Haemodialysis is the most common form of renal replacement therapy. This involves regular filtration of the blood through a dialysis machine in hospital. Most patients need dialysis 3 times per week, with each session lasting 3-5 hours. At least 8 weeks before the commencement of treatment, the patient must undergo surgery to create an arteriovenous fistula, which provides the site for haemodialysis. Most commonly this is created in the lower arm. Some patients may be trained to perform home haemodialysis so that they do not have to regularly attend hospital.

Peritoneal dialysis is another form of renal replacement therapy where the filtration occurs within the patient’s abdomen. Dialysis solution is injected into the abdominal cavity through a permanent catheter. The high dextrose concentration of the solution draws waste products from the blood into the abdominal cavity across the peritoneum. After several hours of dwell time, the dialysis solution is then drained, removing the waste products from the body, and exchanged for new dialysis solution.