Dialysis Indications and Hemodialysis

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Questions and Answers

What primarily drives solute removal in hemodialysis?

Osmotic pressure

Ultrafiltration

Diffusive clearance (correct)

Convective clearance

What is one of the main benefits of early initiation of dialysis?

Increased blood pressure

Reduced exposure to uremic toxins (correct)

Immediate kidney recovery

Enhanced renal function

Which type of dialysate is preferred for elderly and cardiovascular unstable patients?

Sodium containing dialysate

Gluconate containing dialysate

Bicarbonate containing dialysate (correct)

Acetate containing dialysate

What condition is commonly associated with acetate containing dialysate?

Hypotension Signup and view all the answers

What is the purpose of heparin in the dialysis process?

To prevent blood clotting Signup and view all the answers

How does the hemodialysis machine maintain electrolyte concentration?

By controlling the dialysate composition Signup and view all the answers

What type of solution is used in the dialyzer to allow solute exchange?

A dialisate solution separated by a membrane Signup and view all the answers

What is a common sign that dialysis may be required for a patient?

Weight gain from fluid overload Signup and view all the answers

What is the primary method of vascular access for hemodialysis?

Creation of a fistula between an artery and a vein Signup and view all the answers

What is a key disadvantage associated with Continuous Ambulatory Peritoneal Dialysis (CAPD)?

Requires surgical implantation of a catheter Signup and view all the answers

What dietary adjustment is recommended for patients undergoing hemodialysis?

Increase protein intake to 1.2 gm/Kgm/day Signup and view all the answers

What complication is specifically related to the dialysis machine and dialyzer?

Bio-incompatibility of dialyzer membrane Signup and view all the answers

Which of the following is NOT a common complication associated with hemodialysis?

Hypertension Signup and view all the answers

What is the target hemoglobin level for patients receiving recombinant erythropoietin?

11-12 g/dl Signup and view all the answers

How does ultrafiltration occur in peritoneal dialysis?

By creating a hydrostatic pressure gradient Signup and view all the answers

What is a common complication of inadequate dialysis?

Uremia symptoms Signup and view all the answers

What is typically used to create hypertonic dialysate in peritoneal dialysis?

Glucose Signup and view all the answers

What is a major advantage of Continuous Ambulatory Peritoneal Dialysis (CAPD)?

Easy and technically simple for patients Signup and view all the answers

Study Notes

Indications for Dialysis

Dialysis decisions depend on patient symptoms/signs, not just blood urea nitrogen or serum creatinine levels.
Patients starting dialysis with higher residual kidney function have lower morbidity and mortality.
Early dialysis avoids malnutrition, fluid overload, and the harmful effects of prolonged uremic toxin buildup (phosphorus, beta-2-microglobulin, etc.).

Hemodialysis

Hemodialysis replaces two kidney functions: solute removal and fluid removal.
Solute removal in hemodialysis is mainly through diffusion (solutes move from blood to dialysate).
Blood circulates through a semi-permeable membrane (dialyzer) in the machine.
Heparin is used to prevent clotting in the extracorporeal circuit.
Dialysate flows counter-currently to blood through the dialyzer.
The machine controls dialysate temperature, electrolytes, and hydrostatic pressure.
Solute diffusion across the dialyzer membrane happens based on concentration differences.
Dialysate potassium levels are kept low (0-1.5 mEq/L) to prevent potassium buildup.
Dialysate sodium and calcium are kept within normal ranges.
Two types of dialysate are used:
- Acetate dialysate: easier to prepare but can cause hypotension/headache and is less common now.
- Bicarbonate dialysate: preferred for elderly and unstable patients.
Fluid removed during dialysis is accumulated between sessions.
This is achieved by ultrafiltration (using pressure differences across membrane).
Vascular access is a critical requirement for hemodialysis.
- Arteriovenous fistulas (e.g., radial artery/cephalic vein or ulnar artery/basilic vein) are common.
Hemodialysis sessions usually last 4-6 hours, 3 times per week.
Hypertension control is achieved through gradual salt/water removal.
Dietary protein is increased to about 1.2 g/kg/day to avoid malnutrition.
Anemia is treated with iron and erythropoietin, targeting a hemoglobin level of 11-12 g/dL.

Peritoneal Dialysis (CAPD)

Continous Ambulatory Peritoneal Dialysis (CAPD) is a favored choice for some chronic renal failure patients.
A soft silicon catheter (Tenckhoff) is surgically implanted into the abdomen.
Usually, 2 liters of dialysate are run into the peritoneum.
3-5 exchanges are usually needed daily.
Peritoneal dialysis solute/electrolyte removal principles are similar to hemodialysis, but potassium-free dialysate is used.
Ultrafiltration is based on osmosis (hypertonic glucose dialysate).
Dietary protein is increased to about 1.3 g/kg/day in CAPD to compensate for protein loss.
Anemia correction is easier compared to hemodialysis.
Recombinant erythropoietin is the primary treatment.
Target hemoglobin level is 11-12 g/dL.

Advantages of CAPD

Easy to perform and widely available
Removal of large fluid volumes is possible, useful in hemodynamically unstable patients.
Gradual correction of acid-base and electrolyte imbalances is possible.
Easy access placement (especially for children).
No arterial/venous punctures/anticoagulation needed.
Biocompatible

Disadvantages of CAPD

Peritonitis, weight gain, and occasional hernias are possible.

Complications of Hemodialysis

Circulation Access Problems:
- Infection (local or systemic)
- Thrombosis/thrombophlebitis
- Poor peripheral circulation (especially in elderly/diabetics)
Kidney Machine/Dialyzer Problems:
- Membrane bio-incompatibility
- Fluid contamination & complement activation
- Hypersensitivity to sterilization agents (Type I first-use syndrome).
Dialysis Complications (Acute):
- Hypotension/cramps
- Bleeding/blood clot issues
- Air embolisms
- Chest/back pain (possible hypersensitivity)
- Hemorrhage
- Disequilibrium syndrome (rapid urea reduction causing brain edema)
Dialysis Complications (Chronic):
- Hepatitis
- Psychogenic disorders
- Accelerated atherosclerosis
- Carpal tunnel syndrome (beta-2 microglobulin amyloidosis)
Inadequate Dialysis Complications:
- Uremia symptoms, neuropathy, pericarditis
Dialysate-related Complications:
- Hemolysis
- Acidosis
- Aluminum toxicity (avoided by purified water for dialysate preparation)

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Description

This quiz covers key concepts regarding the indications for dialysis and the principles of hemodialysis. Understand the impact of residual kidney function on patient outcomes and the mechanics of solute and fluid removal during treatment. Test your knowledge of important terms and procedures involved in dialysis therapy.