Renal Replacement therapy

Question 1

Renal Replacement Therapy involves

Answer 1

• Mimics functions of kidney
– Excretion of nitrogenous waste
– Maintenance of fluid and electrolytes
• Haemofiltration
• Haemodialysis (HD)
• Peritoneal dialysis (PD)

Question 2

Haemofiltration

Answer 2

• Removal of fluid and electrolytes by convective flow across high-flux permeable membrane
• Volume replaced with solution of desired biochemical composition
• Commonly used continuously in acute setting

Question 3

Haemodialysis

Answer 3

• Fluid and electrolytes removed by diffusion down concentration gradient across semi permeable membrane
• Against dialysate flowing in opposite direction
• Used in CRF
• Usually Intermittent
• Carried out according to prescription
– Individually tailored to each patient
– Based on “Dry weight”
• Frequency & duration
– Adjusted for adequate removal of uraemic metabolites
– To avoid excess fluid overload between sessions
– Usually 4-5 hours 3 times per week

Question 4

HD - complications

Answer 4

• Hypotension
– Excess fluid removal
– Inadequate refilling of blood compartment
– Abnormal venous tone
– Left ventricular hypertrophy
• Cardiovascular disease
• Air embolism
• Sepsis
– Due to access devices

Question 5

Peritoneal Dialysis

Answer 5

• Utilises the peritoneal membrane to act as the semi permeable membrane
– Continuous ambulatory peritoneal dialysis (CAPD)
– Nightly intermittent (NIPD)
– Tidal

Question 6

PD – Complications

Answer 6

• Peritonitis
– Bacterial, fungal
• Constipation
• Fluid leakage
• Failure of membrane
• Sclerosing peritonitis