Dialysis; Types and Importance

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Kelly McCormick
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1 Dialysis; Types and Importance Learning Objectives Dialysis; Definition Dialysis is an artificial procedure that is a substitute for many of the normal duties of the kidneys. Done by cleansing the blood/body fluids by passing it through a special machine. Dialysis; Importance Dialysis is necessary when the kidneys are not able to filter the blood. Dialysis allows patients with kidney failure a chance to live productive lives. Occasionally used for some forms of poisoning Dialysis; Limitations Dialysis is an imperfect treatment to replace kidney function because it does not correct the endocrine functions of the kidney. Types of dialysis There are three primary types of dialysis: hemodialysis peritoneal dialysis, hemofiltration Principles of dialysis Dialysis works on the principles of the diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Blood flows by one side of a semi-permeable membrane, and a dialysate, or special dialysis fluid, flows by the opposite side. A semipermeable membrane is a thin layer of material that contains various sized holes, or pores. Smaller solutes and fluid pass through the membrane, but the membrane blocks the passage of larger substances(proteins, RBCs etc.)

2 Hemodialysis In hemodialysis, a patient's blood is pumped into a dialyzer containing two fluid compartments configured as bundles of hollow fiber capillary tubes or as parallel, sandwiched sheets of semipermeable membranes. Blood in the first compartment is pumped along one side of semipermeable membrane while a crystalloid solution (dialysate) is pumped along other side, in a separate compartment, in opposite direction. Hemodialysis Concentration gradients of solute b/w blood& dialysate lead to desired changes in patient's serum solutes, such as a reduction in urea nitrogen and creatinine; an increase in HCO3; and equilibration of Na, Cl, K, and Mg. The dialysate compartment is under negative pressure relative to the blood compartment to prevent filtration of dialysate into the bloodstream and to remove the excess fluid from the patient. The dialyzed blood is then returned to the patient.

Pericarditis Uremic symptoms GFR < 10 ml/min/1.73 m2 BSA (chronic renal failure, no diabetes) GFR < 15 ml/min/1.

3 Types of vascular access ArterioVenous fistula Arteriovenous graft Central venous catheter Indications of hemodialysis. Renal insufficiency or failure (acute or chronic) with any of the following that cannot otherwise be controlled: Fluid overload Hyperkalemia Hypercalcemia Metabolic acidosis Pericarditis Uremic symptoms GFR < 10 ml/min/1.73 m2 BSA (chronic renal failure, no diabetes) GFR < 15 ml/min/1.73 m2 BSA (chronic renal failure, diabetes) Some poisoning Contraindications for hemodialysis Uncooperative or Hemodynamically unstable patient Complications during dialysis Common: Hypotension (20-50%) Muscle cramps (5-20%) Nausea (5-15%) Headache (5%) Itching (5%) Chest pain/back pain (2-5%)

4 Fever and chills (<1%) Less common but serious Dialysis disequilibrium Arrhythmias Cardiac tamponade Intracranial bleeding Hemolysis Air embolism Peritoneal dialysis Complementary to hemodialysis Peritoneal dialysis uses the peritoneum as a natural permeable membrane through which water and solutes can equilibrate. Peritoneal dialysis is less physiologically stressful than hemodialysis, does not require vascular access, can be performed at home, and allows patients much greater flexibility Peritoneal dialysis; indications Peritoneum (capillary endothelium, matrix, mesothelium) = semipermeable dialysis membrane through which fluid and solute move from blood to dialysis solution via diffusion and convection Effective peritoneal surface area = perfused capillaries closed to peritoneum ( in peritonitis) Ultrafiltration (movement of water) enabled by osmotic gradient generated by glucose or glucose polymers(isodextrin) Peritoneal dialysis; Contraindications Implanted via laparoscopy, punction or laparotomy (total anesthesy) PD is started 3 weeks following the impantation of catheter

5 Peritoneal dialysis; indications Same indications as for hemodialysis (except for poisonings) in patients who: Have inadequate vascular access or Prefer self-therapy Peritoneal dialysis; Contraindications Absolute: Loss of peritoneal function or adhesions that limit dialysate flow, recent abdominal wounds, abdominal fistulas, abdominal wall defects that prevent effective dialysis or increase infection risk (eg, irreparable inguinal or diaphragmatic hernia, bladder extrophy), patient's condition not amenable to dialysis Relative: Abdominal wall infection, frequent episodes of diverticulitis, inability to tolerate large volumes of peritoneal dialysate, inflammatory bowel disease, ischemic colitis, morbid obesity, peritoneal leaks, severe undernutrition Complications of Peritoneal dialysis Infectious: exit-site inflammation (flare, suppurative secretion, granulation) peritonitis (turbid dialysate, abdominal pain, fever) Non-infectious: hernias Hydrothorax Leakage of dialysate along the peritoneal catheter Drainage failure of dialysate (dislocation or catheter obstruction by fibrin) Morphologic changes of peritoneum following long-lasting PD (peritoneal fibrisis, mesotelial damage, vasculopathy and neo-angiogenesis) leading to loss of UF capacity

6 advantages maximum solute clearance best tx for severe hyper-k+ ready availability limited anti-coagulation time bedside vascular access disadvantages hemodynamic instability hypoxemia rapid fluid + solute shifts complex equipment specialized personnel Summary; advantages Summary; Peritoneal Dialysis simple to set up and perform easy to use hemodynamic stability no anti-coagulation bedside peritoneal access disadvantages unreliable ultrafiltration slow fluid + solute removal drainage failure, leakage catheter obstruction respiratory compromise hyperglycemia peritonitis THANK YOU

DIALYSIS COMPACT. The function, diseases and treatments for the human kidney.

DIALYSIS COMPACT. The function, diseases and treatments for the human kidney. DIALYSIS COMPACT The function, diseases and treatments for the human kidney. Content 3 Editorial 4 What do healthy kidneys accomplish? 5 What causes kidney disease? 6 What effects does kidney disease have?