________8_

Renal Dialysis Overview

  • Purpose of Dialysis: Developed to remove excess water and metabolic waste products (toxins) from the body due to inadequate renal function.

  • Common Use: Primarily for patients with End-Stage Renal Disease (ESRD).

Replacement Therapy in Acute Kidney Injury (AKI)

  • Urgent Indications:

    • Remove uraemic toxins when severe symptoms present (e.g., impaired consciousness, seizure, pericarditis).

    • Remove fluid resistant to diuretics (e.g., pulmonary edema).

    • Correct electrolyte and acid-base imbalances (e.g., hyperkalemia, acidosis).

  • Forms of Renal Replacement Therapy:

    • Hemodialysis

    • Hemofiltration

    • Hemodiafiltration

    • Peritoneal dialysis

Dialysate Composition

  • Definition: Dialysate is a mixture of electrolytes in water resembling extracellular fluid that allows solutes to diffuse.

  • Types of Dialysis:

    • Hemodialysis: Preferred for patients with a reduced peritoneal membrane, where anticoagulated blood and dialysate flow in opposite directions through a dialyzer.

Vascular Access for Hemodialysis

  • Importance: Permanent vascular access is crucial for high blood flow necessary for effective hemodialysis.

  • Types of Access:

    • Arteriovenous (AV) fistula

    • AV graft

Hemodialysis Procedure and Complications

  • Procedure Essentials:

    • Patients usually anticoagulated with IV heparin during dialysis.

    • Procedure takes 3-8 hours, typically 3 treatments per week.

  • Common Complications:

    • Intradialytic hypotension (caused by excessive fluid removal).

      • Treatment includes midodrine, sertraline, L-carnitine.

    • Muscle cramps (may require saline infusion and exercise).

    • Hypersensitivity reactions (commonly to dialyzer membranes).

    • Dialysis disequilibrium (prevented by gradual dialysis initiation).

    • Access infections, aluminum toxicity, amyloidosis, malnutrition.

Hemofiltration and Its Uses

  • Overview: An alternative to dialysis emphasizing fluid balance control, utilizing hydrostatic pressure for solute removal.

  • Mechanism: High permeability dialyzer allows substances of molecular weight up to 30,000 to pass, achieving solute clearance primarily through convection.

Haemodiafiltration

  • Technique: Combines features of hemodialysis and hemofiltration for enhanced fluid and solute clearance.

  • Controversy: While offering potential clinical benefits, its efficacy compared to traditional methods is debated.

Peritoneal Dialysis Advantages and Complications

  • Advantages:

    • Cost-effective and simple compared to hemodialysis.

    • Minimal serious complications with patient independence.

  • Complications:

    • Hyperglycemia, constipation, inflammation/infection at catheter site.

    • Discomfort and high incidence of peritonitis, protein loss.

Common Medicines in Dialysis

  • Phosphate Binders:

    • Taken within 30 minutes of meals to bind phosphorus.

  • Antihypertensives:

    • Most agents can be used safely, with specific medications adjusted post-dialysis.

  • Anticoagulants:

    • Low-MW heparin should be avoided in ESRD patients due to accumulation risks.

  • Vitamins and Epoetin:

    • Dialysis removes B vitamins; algo must manage epoetin injections due to decreased levels in ESRD.

  • L-carnitine:

    • Important for energy management; deficiencies common in dialysis patients; improves various complications.

  • Analgesics:

    • Paracetamol preferred for pain; NSAIDs avoided due to risks.

Antimicrobials and Diabetes Medications in Dialysis

  • Adjustments Made:

    • Antibiotics often require dose reductions in dialysis patients.

    • Dipeptidyl peptidase-4 inhibitors vary in suitability; metformin is contraindicated to prevent lactic acidosis.

    • Sodium-glucose co-transporter inhibitors advised against due to dependence on renal function.

Conclusion

  • Dialysis plays a critical role in the management of patients with renal failure, providing essential treatment options to manage fluid, electrolyte, and waste products effectively. Proper understanding of the therapies available and their complications is essential for effective patient management.