Chapter 46: Dialysis and Kidney transplant Flashcards
What is dialysis?
What is it used for?
Indications?
Movement of fluid/molecules across semipermeable membrane from oe compartment to another
corrects fluid/electrolyte imbalances and removes waste products in kidney failure –> can also treat drug overdoses
A-acidosis
E - electrolytes (hyperkalemia)
I - ingestion (of drugs)
O - overload of fluid
U - uremia –> encephilitis/pericarditis
Methods of dialysis
When to start dialysis
2 methods: Peritoneal dialysis (PD) and hemodialysis (HD)
Started when patient’s uremia can’t be treated conservatively (GFR , 15 ml/min/1.73 m^2)
Why do people with ESRD get dialysis
lack of donated organs
some ppl are mentally or physically unsuitable for transplantation
some ppl don’t want transplants
3 general principles of dialysis
Diffusion
Osmosis –> glucose in dialysate pulls fluid from blood
Ultrafiltration = water and fluid removal
-results from osmotic or pressure gradient across membrane
-PD = osmotic; HD = pressure
-Excess fluid moves into dialysate
Peritoneal Dialysis: catheter insertion
through anterior abdominal wall
usually done via surgery, but technique varies
Might start right away, or might wait for site to heal
ASEPTIC TECHNIQUE to avoid peritonitis
Three phases of manual PD cycle
- Inflow (fill) –> 2-3 L over 10 mins –> volume depends on size of cavity
- Dwell (equilibration) –> 20 mins to 8 hrs (usually 4-6 hrs)
- drain –> 15-30 mins
Together, its called “exchange”
Dextrose is the osmotic agent
2 types of PD systems
Automated peritoneal dialysis (APD)
-cycler delivers dialysate during sleep times and controls the 3 phases
-alarms and monitors for safety
-usually also need 1 or 2 day time exchanges
Continuous Ambulatory Peritoneal Dialysis (CAPD)
-Manual exchange 4 times during the day
-dwell time usually 4 hrs
PD complications (list them)
Exit site infections - red, tender, drainage –> give antibiotics
Peritonitis - i’ll elaborate
Hernias - from pressure from dialysate –> repair hernia
Lower back probs – pressure again –> treat w/ binders and exercise
Bleeding- initial placement –> if active intraperitoneal bleeding, check BP and hct
Pulmonary probs - less expansion –> atelectasis, pneumonia, or bronchitis - elevate head of bed, reposition, deep breathing
Protein loss - monitor nutrition
PD complication: Peritonitis
Exit site or tunnel infection
-Abdominal pain, rebound tenderness, or cloudy effluent with increased WBCs or bacteria–> may have fever
-GI = diarrhea, vomiting, distention, increased bowel sounds
-treat with antibiotics
-repeated infections may cause adhesions
HD requirements
HD problems
requires rapid blood flow and access to large blood vessel
obtaining vascular access is prob
Types of access = arteriovenous fistulas/grafts or temporary vascular access
Arteriovenous fistulas
created in forearm or upper arm (preferred)
fisula lets arterial blood flow through vein –> becomes “arterialized”
vein gets bigger with thicker walls
placed 3 months before HD so it can mature
Feel “thrill” or hear “bruit” due to high velocity of blood flow
Arteriovenous grafts (AVGs)
how long does it take to heal?
common problems
Synthetic material surgically placed under skin to form bridge bt artery (brachial) and vein (antecubital)
takes 2-4 weeks to heal
more likely to get infected or form clots –> if infected, remove
HeRO graft (hemodialysis reliable outflow)
Special bridge access used when other options are exhausted
2 pieces:
-reinforced tube to bypass blockages
-dialysis graft anastomosed to an artery placed under skin
-bypasses venous system –> flows from target artery to heart
Risks of AV fistulas and grafts
Distal ischemia (steal syndrome)
-pain distal to access site
-numbness and tingling of fingers
-poor capillary refill
Aneurysms
Don’t take BP, do venipunctures, or insert IVs in extremity with one of these
-prevent infection and clotting
Temporary vascular access
risks?
Catheter is inserted in internal jugular or femoral vein when access is needed
Double lumen for blood removal and return
Risks: high infection, dislodgement, and malfunction
Temporary vascular access: long term cuffed catheters
used when waiting for AVF or if other forms failed
-exit on upper chest and tunneled to internal or external jugular vein
-tip in right atrium
-one or two cuffs prevent infection and anchor catheter
