Renal Dialysis (Clinical Demonstration)

Question 1

What is meant by pre-acute renal failure?

Answer 1

Where there is reduced renal blood flow and therefore reduced filtration

Question 2

What is meant by intrinsic renal failure?

Answer 2

This is here there is acute injury to the glomerulus, tubules, interstitium or vessels, and is referred to as AKI (Acute kidney injury)

Question 3

What is meant by post-acute renal failure?

Answer 3

Where there is obstructed urinary flow which causes an increased back-flow and pressure on the renal tubules

Question 4

What is meant by chronic renal failure?

Answer 4

Long-standing, irreversible decline of renal function where injured nephrons are fibroses and remaining nephrons gradually fail due to their over-compensatory hyperfiltration

Question 5

What is a characteristic difference between chronic and acute renal failure?

Answer 5

In chronic renal failure there is tubular scarring rather than glomerular damage; therefore urinary output is often normal despite urine quality being reduced

Question 6

What are the common causes of chronic renal failure?

Answer 6

Hypertension, diabetes, polycystic kidneys and indolent GN

Question 7

How may you assess renal function?

Answer 7

Urea and creatinine levels to test for clearance or build-up, and measure GFR (can be estimated via the MDRD equation which requires creatinine, age, sex and race)

Question 8

What are the complications of renal failure (SWEAT)?

Answer 8

Salt
Water - less water excreted –> volume overload –> hypertension
Electrolytes - hyperkalaemia can result from reduced urinary output which can cause arrhythmias and cardiac stoppage
Acidosis - decreased ability of the kidney to excrete excess H+ lead to acidosis which can cause myocardial depression and instability
Toxins - reduced urea clearance which can lead to pericarditis, effusions and encephalopathy as a result.

Question 9

What is the main aim of dialysis?

Answer 9

To remove the excess SWEAT molecules to support the failing kidneys and this relies diffusion and convection to re-establish the physiologic balance

Question 10

What are the four options an individual has when they experience renal failure?

Answer 10

• Conservative and expectant treatment
• Haemodialysis
• CAPD (peritoneal dialysis)
• Transplantation

Question 11

What is the difference between diffusion and convection in the context of renal dialysis?

Answer 11

Diffusion involves the movement of molecules along their concentration gradient.

Convection involves the movement of solutes in a fluid to areas of lower pressure.

Question 12

Describe the process of haemodialysis

Answer 12

This involves the use of an artificial membrane 3 times a week for about 4 hours; an access permacath line is inserted into the IJV or an arteriovenous fistula is created

Question 13

What are the potential complications of haemodialysis?

Answer 13

Complications mainly stem from issues with access which can lead to infections, thrombosis or simply lack of access, or hypotension.

Question 14

Describe the process of peritoneal dialysis

Answer 14

The peritoneal cavity is filled with fluid approximately 4 times a day and takes about half an hour.

Question 15

What are the potential complications of peritoneal dialysis?

Answer 15

Peritonitis and peritoneal membrane dysfunction

Question 16

What are the advantages of peritoneal dialysis?

Answer 16

It is a continuous treatment that is less demanding on the CVS, it is independent but can be assisted also.

Question 17

What are the disadvantages of peritoneal dialysis?

Answer 17

Patients require competence in order to be able to self-regulate their ‘SWEAT’ molecules, and if there is membrane failure and any abnormal glycosylation this can lead to further complications, and residual renal function is still required.