Dialysis

Blood Filtration and Cleaning

  • Blood filtered and cleaned in the dialyzer machine

  • Dialysis

Dialysis Overview

  • Definition:

    • Movement of fluid/molecules across a semipermeable membrane from one compartment to another.

  • Purpose:

    • Corrects fluid and electrolyte imbalances and removes waste products in kidney failure.

    • Can also treat drug overdoses.

Methods of Dialysis

  • Two methods of dialysis available:

    • Peritoneal Dialysis (PD)

    • Hemodialysis (HD)

  • Indication for Starting Dialysis:

    • When a patient’s uremia cannot be treated conservatively.

    • When Glomerular Filtration Rate (GFR) < 15 mL/min/1.73 m², as determined by a nephrologist.

    • Uremic complications necessitate dialysis.

End-Stage Renal Disease (ESRD) and Dialysis

  • Reasons ESRD is treated with dialysis:

    • Lack of available donated organs.

    • Certain patients may be unsuitable for transplantation (physically or mentally).

    • Some patients refuse to have transplants.

    • Age is not a determining factor for candidacy in transplant eligibility.

Principles of Dialysis: Osmosis and Diffusion

  • Osmosis:

    • The movement of fluid from an area of lesser solute concentration to an area of greater concentration.

    • In dialysis, glucose in the dialysate creates an osmotic gradient pulling fluid from the blood.

  • Ultrafiltration:

    • Refers to water and fluid removal when there is an osmotic or pressure gradient across the dialyzer membrane.

    • Peritoneal Dialysis: Glucose in dialysate establishes an osmotic gradient.

    • Hemodialysis: Utilizes a pressure gradient where excess fluid migrates into the dialysate.

Peritoneal Dialysis

  • Process:

    • Peritoneal access is achieved through catheter insertion into the anterior abdominal wall.

    • The placement technique can vary and typically occurs surgically.

    • PD may be initiated immediately or delayed until the catheter site has healed.

    • Importance of Aseptic Technique:

    • Critical to prevent peritonitis.

  • Complications of Peritoneal Dialysis:

    • Exit Site Infection:

    • Symptoms: Redness, tenderness, and drainage at the catheter site.

    • Treatment: Antibiotics.

    • Peritonitis:

    • Indicators: Abdominal pain, rebound tenderness, cloudy effluent with increased WBCs, fever, and gastrointestinal symptoms (diarrhea, vomiting).

    • Treatment: Antibiotics, as it may lead to adhesions with repeated infections.

    • Hernias:

    • Cause: Increased intrabdominal pressure from dialysate.

    • Treatment: Hernia repair.

    • Lower Back Problems:

    • Caused by increased abdominal pressure due to fluid infusion.

    • Treatment includes binders and exercise.

    • Bleeding:

    • Commonly occurs with initial catheter placement; assess for active intraperitoneal bleeding.

    • Pulmonary Complications:

    • Issues such as atelectasis, pneumonia, or bronchitis might develop due to decreased lung expansion.

    • Management includes elevating the head of the bed and encouraging deep breathing exercises.

    • Protein Loss:

    • Nutritional status needs to be monitored regularly.

Effectiveness of Peritoneal Dialysis

  • Advantages of Chronic PD:

    • Simplicity of setup.

    • Home-based program enhances patient participation.

    • Reduces the need for special water systems for dialysis.

    • Equipment setup is relatively simple and only requires 3 to 7 days of training.

Hemodialysis (HD) 

  • Vascular Access Requirements for HD:

    • Requires swift blood flow and access to a large blood vessel.

    • One of the primary challenges is obtaining vascular access.

  • Types of Vascular Access:

    • Arteriovenous Fistulas (AVF): Preferred for HD; these are created using the forearm/upper arm veins.

    • Arteriovenous Grafts (AVG): Formed using synthetic material as a ‘bridge’ between artery and vein.

    • Temporary Vascular Access: Involves catheter insertion of the internal jugular or femoral vein when immediate access is necessary.

  • Creating Arteriovenous Fistulas:

    • Arteriovenous fistulas promote arterial blood flow into veins, causing them to “arterialize” over time (3-month maturation prior to use).

    • Patients feel a “thrill” or hear a “bruit” due to high blood flow velocity.

  • Risks Associated with AVF and AVG:

    • Conditions such as distal ischemia (steal syndrome), pain or numbness distal to access site, and poor capillary refill.

    • Safety Alerts:

    • Avoid blood pressure readings, venipunctures, and IV lines in the area of access.

    • Infection prevention and management of clotting is critical.

Hemodialysis Procedure

  • Dialyzer Functionality:

    • Blood is pumped into hollow fibers in a dialyzer where diffusion and osmosis occur.

    • The dialysate bathes the outside of the fibers and facilitates ultrafiltration.

    • Once treated, blood is returned to the patient.

  • Before HD Treatment Assessment:

    • Check fluid status (weight, blood pressure, and heart and lung sounds).

    • Weigh patient pre-dialysis to determine fluid removal.

    • Assess vascular access and record vital signs (VS) every 30 to 60 minutes.

  • HD Treatment Process:

    • Use 2 large bore needles: one to withdraw blood for treatment, the other to return dialyzed blood.

    • Heparin is infused to prevent clotting.

    • The entire system is primed with saline to eliminate air before starting.

    • Post-treatment: flush with saline to ensure all blood is returned; apply firm pressure after needle removal.

  • Dialysis Scheduling:

    • Most patients are treated 3 to 4 hours, three times a week. Other options include:

    • Short daily HD

    • Long nocturnal HD

    • Home HD

Hemodialysis Complications

  • Common Complications:

    • Hypotension: Resulting from hypovolemia; symptoms include lightheadedness, nausea, and chest pain.

    • Treatment involves decreasing the volume of fluid removed and administering IV NSS.

    • Muscle Cramps: May occur due to decreased blood pressure or increased ultrafiltration.

    • Treatments include reducing ultrafiltration and administering IV fluids.

    • Blood Loss: Can happen if blood is not adequately rinsed from the dialyzer or during procedural mishaps.

    • Treatment involves rigorous monitoring of heparin use, rinsing of blood, and applying pressure to access sites.

    • Hepatitis Risks:

    • Infection control precautions must be in place due to hepatitis risks (8% to 10% for hepatitis C).

    • Administering the hepatitis B vaccine can reduce low incidence rates.

Effectiveness of Hemodialysis

  • Limitations:

    • Hemodialysis cannot fully replace kidney functions but can alleviate symptoms and prevent certain complications.

    • Notably, cardiovascular disease exhibits a high mortality rate among dialysis patients, with infectious complications being the second leading cause of death.

  • Patient Adaptation:

    • Responses can vary from positive to ambivalent or depressed.

  • Nursing Goals:

    • Facilitate a healthy self-image and promote the highest level of functional return, including reintegration into work.

Continual Renal Replacement Therapy (CRRT)

  • Purpose:

    • Method for treating Acute Kidney Injury (AKI), enabling the removal of uremic toxins and fluids, and adjusting acid-base and electrolyte balance smoothly.

    • This method is effective in hemodynamically unstable patients and can run over 24 hours; it can also be employed alongside HD.

  • Contraindications:

    • Life-threatening uremic manifestations that necessitate rapid intervention.

  • Types of CRRT:

    • Continuous Venovenous Hemofiltration (CVVH)

    • Slow Continuous Ultrafiltration (SCUF)

    • Continuous Venovenous Hemodialysis (CVVHD)

    • Continuous Venovenous Hemodiafiltration (CVVHDF)

  • Note:

    • CVVHD and CVVHDF utilize dialysate attached at the distal end of a hemofilter.

  • Operation of CRRT:

    • Customized infusion of replacement fluids based on fluid and electrolyte imbalance.

    • Anticoagulants are critical to prevent clotting.

  • CRRT vs. HD:

    • CRRT features a slower blood pump and operates continuously as opposed to intermittently, allowing fluid volume removal over longer periods.

    • It utilizes convection for solute removal without a dialysate in addition to osmosis and diffusion, leading to less hemodynamic instability and less monitoring requirement compared to HD.

    • CRRT can be sustained for extended periods (30 to 40 days) while requiring frequent hemofilter changes (every 24 to 48 hours).

  • Nursing Interventions:

    • Use weights, monitor lab values regularly, and ensure site care to prevent infection.

Kidney Transplantation

  • Overview:

  • More than 100,000 patients await kidney transplants; average wait time for cadaver donations is between 2 to 5 years, with 17,000 transplants occurring annually.

  • Advances in organ procurement, surgical techniques, tissue typing, and immunosuppressant therapy have improved the field materially.

    • Transplant Effectiveness:

  • Considered the best treatment for ESRD, demonstrating high success rates:

    • One-year graft survival:

    • 90% for deceased donor transplants.

    • 95% for live donor transplants.

  • This treatment effectively reverses the underlying pathophysiology of ESRD, eliminating the need for dialysis and dietary/lifestyle restrictions post-transplant, ultimately proving less costly than dialysis after the first year.

    • Recipient Selection for Transplant:

  • Candidacy relies on a variety of medical and psychosocial factors, subject to regional policies.

  • Possible exclusions include obesity and smoking.

  • Preemptive transplants (prior to the need for dialysis) are viable with a living donor.

    • Contraindications for Transplant Candidates:

  • Advanced cancers, refractory heart disease, chronic respiratory failure, extensive vascular disease, unresolved psychosocial disorders.

  • Notably, HIV+ and hepatitis B or C status are not automatically contraindications.

    • Donor Sources:

  • Compatible blood type deceased donors, blood relatives, emotionally related living donors, altruistic living donors, and paired organ donations.

    • Live Donor Advantages:

  • Provides better patient and graft survival rates, immediate organ availability, and offers the chance to optimize recipient health conditions pre-transplant due to elective nature.

  • Extensive evaluations (including ECG, chest x-rays) are performed to ensure donor health, including psychosocial assessments to gauge emotional stability and understanding of surgery risks.

    • Deceased Donor Overview:

  • Typically consist of individuals who have experienced irreversible brain injury with effective cardiovascular functions.

  • Legal permission is sought for organ removal, and preserved organs are favored for transplantation within 24 hours.

    • Kidney Transplant Surgical Procedure:

  • A two-step process: donor nephrectomy occurs one to two hours before the recipient's procedure, performed by specialized transplant surgeons.

    • Postoperative Care Management:

  • Essential to avoid dehydration and recognize symptoms related to electrolyte imbalances or acute tubular necrosis, alongside education regarding signs of rejection, infection, or surgical complications.

    • Complications Post-Transplant:

  • Potential for acute or chronic rejection, infections (e.g., pneumonia, UTIs), cardiovascular diseases (monitoring for hypertension), cancers (due to immunosuppression), and recurrence of original kidney diseases.