Dialysis

Continual Renal Replacement Therapy (CRRT)

-Method for treating AKI -Means by which uremic toxins and fluids are removed -Acid-base status/electrolyte are adjusted slowly and continuously -Can be used in conjunction with HD -Contraindication: Patient has life-threatening manifestations of uremia that require rapid treatment

Drain

-Lasts 15 to 30 minutes -May be facilitated by gently massaging abdomen or changing position -Ultrafiltration during PD depends on osmotic forces

Hemodialysis: Settings and Schedules

-Majority treated in a community-based center -Dialyzed for 3 to 4 hours 3 days per week -Other schedule options Short daily HD Long nocturnal HD Home HD

Continuous ambulatory peritoneal dialysis (CAPD)

-Manual exchange during the day -manually with 2 to 3 L of peritoneal dialysate four times daily, with dwell times averaging 4 hours

Dialysis

-Movement of fluid/molecules across a semipermeable membrane from one compartment to another -Used to correct fluid and electrolyte imbalances and to remove waste products in kidney failure -Can be used to treat drug overdoses

Osmosis

-movement of fluid from an area of lesser concentration of solutes to area of greater concentration -Glucose is added to the dialysate and creates an osmotic gradient across the membrane, pulling excess fluid from the blood.

Dialysis begins when:

-patient's uremia can no longer be adequately treated conservatively -when GFR < 15 mL/min/1.73 m2

Dwell

-Also known as equilibration -Diffusion and osmosis occur between patient's blood and peritoneal cavity -Duration of dwell time varies, depending on method of PD

A patient undergoes peritoneal dialysis exchanges several times each day. What should the nurse plan to increase in the patient's diet? A. Fat B. Protein C. Calories D. Carbohydrates

-Answer: B -Rationale: Dietary protein guidelines for peritoneal dialysis (PD) differ from those for hemodialysis because of protein loss in the dialysate. During PD, protein intake must be high enough to compensate for the losses, so that the nitrogen balance is maintained. Recommended protein intake is at least 1.2 g/kg of ideal body weight per day, and it increases according to the individual needs of the patient.

Hemodialysis: Before beginning treatment assessment

-Assess fluid status (weight, BP, peripheral edema, lung and heart sounds), condition of vascular access, and temperature -Difference between last postdialysis weight and present predialysis weight determines ultrafiltration (amt of weight from fluid to be removed)

Peritoneal Dialysis: Dialysis Solutions

-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

Hemodialysis Effectiveness

-Cannot fully replace normal functions of kidneys -Can ease many of symptoms -Can prevent certain complications

CRRT versus HD

-Continuous rather than intermittent -Fluid volume can be removed over days versus hours -Solute removal by convection (no dialysate required) in addition to osmosis and diffusion -Less hemodynamic instability -Does not require constant monitoring by HD nurse -Does not require complicated HD equipment

Automated peritoneal dialysis (APD)

-Cycler delivers the dialysate -Times and controls fill, dwell, and drain phases -Allows patients to accomplish dialysis while they sleep -Cycles four or more exchanges per night with 1 to 2 hours per exchange -difficult to achieve the required solute and fluid clearance solely with nighttime APD. One or two daytime manual exchanges also be prescribed to ensure adequate dialysis.

Peritoneal Dialysis Complications

-Exit site infection: by Staphylococcus aureus or Staphylococcus epidermidis (from skin flora). -Peritonitis: improper technique when connections for exchanges are contaminated -Hernias: increased intraabdominal pressure secondary to the dialysate volume Increased risk in multiparous women and older men -Lower back problems: Increased intraabdominal pressure -Bleeding: check the BP and hematocrit -Pulmonary complications: Atelectasis, pneumonia, and bronchitis from repeated upward displacement of the diaphragm=decreased lung expansion -Protein loss: unresolved peritonitis=malnutrition=terminate PD temp/perm

Hemodialysis: Complications

-Hypotension: from rapid removal of vascular volume (hypovolemia), decreased cardiac output, and decreased systemic intravascular resistance -Muscle cramps: hypotension, hypovolemia, high ultrafiltration rate (large interdialytic weight gain), and low-sodium dialysis solution -Loss of blood: blood not being completely rinsed from the dialyzer, accidental separation of blood tubing, dialysis membrane rupture, or bleeding after the removal of needles at the end of HD -Hepatitis: Hep C most prevelent

Continual Renal Replacement Therapy

-Infusion of replacement fluid determined by degree of fluid and electrolyte imbalance -Anticoagulants are needed to prevent blood clotting -Ultrafiltrate should be clear yellow

Diffusion

-Movement of solutes from an area of greater concentration to an area of lesser concentration -In kidney failure, urea, creatinine, uric acid, and electrolytes (potassium, phosphate) move from the blood to the dialysate with the net effect of lowering their concentration in the blood.

Continual Renal Replacement Therapy Interventions

-Obtain weights -Monitor and document laboratory values daily -Assess hourly Intake and output Vital signs Hemodynamic status -Care for site to prevent infection

Hemodialysis Dialyzers

-Plastic cartridge that contain thousands of parallel hollow tubes or fibers -Fibers are semipermeable membranes -Dialysis fluid (dialysate) is pumped into the bottom of the cartridge and bathes the outside of the fibers -When the dialyzed blood reaches the end of the thousands of semipermeable fibers, it converges into a single tube that returns it to the patient

Wearable Artificial Kidney (WAK)

-Recently developed and approved for use -Miniaturized dialysis machine -Carrier resembles a tool belt -Connects to patient via catheter -Designed to filter blood in ESRD -Can run continuously

Effectiveness of Chronic PD

-Short training program -Advantages Simplicity Home-based program Increasing patient participation No need for special water systems Equipment set-up is relatively simple

Hemodialysis: During treatment assessment

-Take vital signs every 30 to 60 minutes

Three phases of PD cycle

-The 3 phases are called an exchange Inflow (fill) Dwell (equilibration) Drain

ESRD 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

Hemodialysis Procedure

-Two needles placed in fistula or graft One needle is placed to pull blood from circulation to HD machine Other needle is used to return dialyzed blood to the patient -Dialyzer/blood lines primed with saline solution to eliminate air -Terminated by flushing with saline to return all blood to patient -Needles removed and firm pressure applied -Heparin is added to prevent clotting

CVVHD and CVVHDF

-Uses dialysate -Dialysis fluid is attached to distal end of hemofilter -ideal treatment for a patient who needs both fluid and solute control but cannot tolerate the rapid fluid shifts associated with HD.

Ultrafiltration

-Water and fluid removal -Results when there is an osmotic gradient or pressure gradient across membrane -Excess fluid moves into dialysate

Clinical manifestation of peritonitis

-abdominal pain, rebound tenderness, and cloudy peritoneal effluent with a WBC count greater than 100 cells/µL (more than 50% neutrophils) or demonstration of bacteria in the peritoneal effluent by Gram stain or culture -diarrhea, vomiting, abdominal distention, and hyperactive bowel sounds, Fever

Continuous Venovenous Therapies

-blood pump propels blood through the circuit. -highly permeable, hollow-fiber hemofilter removes plasma water and nonprotein solutes, which are collectively termed ultrafiltrate. -ultrafiltration rate (UFR): 0 to 500 mL/hr. -Under the influence of hydrostatic pressure and osmotic pressure, water and nonprotein solutes pass out of the filter into the extracapillary space and drain through the ultrafiltrate port into a collection device (drainage bag). -The remaining fluid continues through the filter and returns to the patient via the return port of the double-lumen catheter. -As ultrafiltrate drains out of the hemofilter, fluid and electrolyte replacements can be infused through a port located before or after the filter as the blood returns to the patient. -Replacement fluid is designed to replace volume and solutes such as sodium, chloride, bicarbonate, and glucose.

Tenckhoff Catheter

-catheter is about 24 inches (60 cm) long and has one or two Dacron cuffs. -cuffs act as anchors and prevent the migration of microorganisms into the peritoneum. -tip of the catheter rests in the peritoneal cavity and has many perforations spaced along the distal end of the tubing, allowing fluid movement through the catheter.

Arteriovenous fistula

-created by anastomosing an artery and vein -allows arterial blood to flow through the vein -vein becomes "arterialized" increasing in size and developing thicker walls -provide the rapid blood flow required for HD -a thrill (buzzing sensation) can be felt by palpating the fistula, and a bruit (rushing sound) can be heard with a stethoscope -created by arterial blood moving at a high velocity through the vein

Preparation of the patient for Tenckhoff catheter insertion includes:

-emptying the bladder and bowel, weighing the patient, and obtaining a signed consent form. -After placement, PD may be initiated immediately with low volume exchanges, or delayed for 2 weeks pending healing and sealing of the exit site.

In HD, the osmotic gradient is created by:

-increasing pressure in the blood compartment (positive pressure) or decreasing pressure in the dialysate compartment (negative pressure).

In PD, excess fluid is removed by:

-increasing the osmolality of the dialysate (osmotic gradient) with the addition of glucose

Peritoneal access is obtained by:

-inserting a catheter through anterior abdominal wall -Technique for catheter placement varies -Usually done via surgery

HeRO Graft(Hemodialysis Reliable Outflow)

-two pieces: a reinforced tube to bypass blockages in veins and a dialysis graft anastomosed to an artery to be accessed for HD -placed under the skin, like both a fistula and standard graft -bypasses the venous system to provide blood flow directly from a target artery to the heart -Used when other access options are exhausted

Subcutaneous arteriovenous fistula (AVF)

-usually created in the forearm or upper arm with an anastomosis between an artery and a vein (usually cephalic or basilic)

Hemodialysis (HD)

an artificial membrane (usually made of cellulose-based or synthetic materials) is used as the semipermeable membrane and is in contact with the patient's blood.

Inflow

Prescribed amount of solution infused through established catheter over about 10 minutes After solution infused, inflow clamp closed

Peritoneal dialysis (PD)

the peritoneal membrane acts as the semipermeable membrane