Dialysis Chapter 47
Dialysis • Movement of fluid/molecules across a semipermeable membrane from one compartment to another • Used to correct fluid/electrolyte imbalances and to remove waste products in renal failure • Treat drug overdoses
Dialysis • Two methods of dialysis available • Peritoneal dialysis (PD) • Hemodialysis (HD)
Dialysis • Begun when patient’s uremia can no longer be adequately managed conservatively • Initiated when GFR (or creatinine clearance) is less than 15 mL/min
Dialysis • ESKD treated with dialysis because • There is a lack of donated organs • Some patients are physically or mentally unsuitable for transplantation • Some patients do not want transplants
General Principles of Dialysis • Diffusion • Movement of solutes from an area of greater concentration to an area of lesser concentration
General Principles of Dialysis • Osmosis • Movement of fluid from an area of lesser concentration of solutes to area of greater concentration
General Principles of Dialysis • Ultrafiltration • Water and fluid removal • Results when there is an osmotic gradient across the membrane
Case Study Purestock/Thinkstock • K.W., a 35-year-old man, received a diagnosis of chronic glomerulonephritis (see case study in PowerPoint presentation on chronic kidney disease). • He has now reached stage 5 chronic kidney disease.
Case Study Purestock/Thinkstock • K.W.’s laboratory values: • BUN 72 mg/dL • Serum creatinine 6.5 mg/dL • GFR 12 mL/min • What are his treatment options at this time?
Peritoneal Dialysis • Peritoneal access is obtained by inserting a catheter through the anterior abdominal wall • Technique for catheter placement varies • Usually done via surgery
Case Study Purestock/Thinkstock • K.W. decides to use peritoneal dialysis (PD) as his treatment. • He has a Tenckhoff catheter placed for PD. • He asks many questions about when he can begin using the catheter, as well as how he will manage his dialysis schedule.
Peritoneal Dialysis • After catheter inserted, skin is cleaned with antiseptic solution and sterile dressing applied • Connected to sterile tubing system • Secured to abdomen with tape • Catheter irrigated immediately
Peritoneal Dialysis • Waiting period of 7 to 14 days preferable • Two to 4 weeks after implantation, exit site should be clean, dry, and free of redness/tenderness • Once site healed, patient may shower and pat dry
Peritoneal DialysisDialysis Solutions and Cycles • Available in 1- or 2-L plastic bags with glucose concentrations of 1.5%, 2.5%, and 4.25% • Electrolyte composition similar to that of plasma • Solution warmed to body temperature
Peritoneal DialysisDialysis Solutions and Cycles • Three phases of PD cycle • Inflow (fill) • Dwell (equilibration) • Drain • Called an exchange
Peritoneal DialysisDialysis Solutions and Cycles • Inflow • Prescribed amount of solution infused through established catheter over about 10 minutes • After solution infused, inflow clamp closed to prevent air from entering tubing
Peritoneal DialysisDialysis Solutions and Cycles • Dwell • Also known as equilibration • Diffusion and osmosis occur between patient’s blood and peritoneal cavity • Duration of time varies, depending on method
Peritoneal DialysisDialysis Solutions and Cycles • Drain • Lasts 15 to 30 minutes • May be facilitated by gently massaging abdomen or changing position
Peritoneal DialysisSystems • Automated peritoneal dialysis (APD) • Cycler delivers the dialysate • Times and controls fill, dwell, and drain • Continuous ambulatory peritoneal dialysis (CAPD) • Manual exchange
Peritoneal DialysisComplications • Exit site infection • Peritonitis • Hernias
Peritoneal DialysisComplications • Lower back problems • Bleeding • Pulmonary complications • Protein loss
Peritoneal DialysisEffectiveness and Adaptation • Short training program • Independence • Ease of traveling • Fewer dietary restrictions • Greater mobility than with HD
Case Study Purestock/Thinkstock • K.W. has difficulty managing his P.D. because of progressive visual limitations. • He develops a catheter infection, and it is determined that he should be switched to hemodialysis (HD).
HemodialysisVascular Access Sites • Obtaining vascular access is one of most difficult problems • Types of access • Arteriovenous fistulas and grafts • Temporary vascular access
HemodialysisDialyzers • Long plastic cartridges that contain thousands of parallel hollow tubes or fibers • Fibers are semipermeable membranes
HemodialysisProcedure • Two needles placed in fistula or graft • One needle is placed to pull blood from the circulation to the HD machine • The other needle is used to return the dialyzed blood to the patient
HemodialysisProcedure • Dialyzer/blood lines primed with saline solution to eliminate air • Terminated by flushing dialyzer with saline to remove all blood • Needles removed and firm pressure applied
Case Study Purestock/Thinkstock • K.W. has a left arteriovenous fistula placed. • After 1 month, he is ready to begin HD. • What assessment data should be obtained before a dialysis treatment is initiated?
HemodialysisProcedure • Before treatment, nurse should • Complete assessment of fluid status, condition of access, temperature, skin condition • During treatment, nurse should • Be alert to changes in condition • Measure vital signs every 30 to 60 minutes
HemodialysisComplications • Hypotension • Muscle cramps • Loss of blood • Hepatitis
HemodialysisEffectiveness and Adaptation • Cannot fully replace normal functions of kidneys • Can ease many of the symptoms • Can prevent certain complications
Continual Renal Replacement Therapy (CRRT) • Alternative or adjunctive method for treating AKI • Means by which uremic toxins and fluids are removed • Acid-base status/electrolyte balance adjusted slowly and continuously
Continual Renal Replacement Therapy (CRRT) • Can be used in conjunction with HD • Contraindication • Presence of manifestations of uremia that necessitate rapid resolution • Continued for 30 to 40 days
Continual Renal Replacement Therapy (CRRT) • Hemofilter change every 24 to 48 hours • Ultrafiltrate should be clear yellow • Specimens may be obtained for evaluation
Continual Renal Replacement Therapy (CRRT) • Two types of CRRT • Venous access • Arterial access
Continual Renal Replacement Therapy (CRRT) • Most common approaches: venovenous • Continuous venovenous hemofiltration (CVVH) • Continuous venovenous hemodialysis (CVVHD)
Continual Renal Replacement Therapy (CRRT) • Continuous venovenous hemofiltration (CVVH) • Large volumes fluid removed hourly, then replaced • Fluid replacement dependent on stability/individualized needs of patient
Continual Renal Replacement Therapy (CRRT) • Continuous venovenous hemodialysis (CVVHD) • Uses dialysate • Dialysate bags attached to distal end of hemofilter