Term
| What criteria would qualifty someone for dialysis? |
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Definition
- "Chronic Renal Replacement"
- GFR <15 ml/min1.73m2
- Symptoms of uremia/uremic syndrome
- Clinical presentation |
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Term
| What are the goals of dialysis? |
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Definition
- Renal replacement therapy for impaired kidney not able to meet body's metabolic needs
- Removal of endogenous waste
- Correcting acid-base and electrolyte disturbances
- Achieving Dry Weight (volume homeostasis) --> Target post-dialysis weight at which the patient is normotensive and free of edema
- Lowering morbidity and mortality |
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Term
| What is Diffusion? What are the factors that affect the rate of diffusion? |
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Definition
Diffusion - Movement of substances along a concentration gradient
Rates of Diffusion:
- Flow rates
- Concentration of solutes
- Dialyzer
- Types of solutes |
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Term
| What is Ultrafiltration? Describe the process |
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Definition
Ultrafiltration = Convection = Movement of water across a membrane due to hydrostatic or osmotic pressure
Process:
- Solutes dragged across membrane (convection)
- Primary means for water removal
- Can be maximized by increasing pressure across membrane, or changing dialyzer |
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Term
| What are some examples of Continuous Renal Replacement Therapy, their mechanism, and their level of fluid replacement? |
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Definition
|
Technique
|
Clearance Mechanism
Convection Diffusion
|
Fluid Replacement
|
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SCUF
|
+
|
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0
|
|
CAVH
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++++
|
|
+++
|
|
CVVH
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++++
|
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+++
|
|
CAVHD
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+
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++++
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+/0
|
|
CVVHD
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+
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++++
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+/0
|
|
CAVHDF
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+++
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+++
|
++
|
|
CVVHDF
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+++
|
+++
|
++
|
|
CAVHFD
|
++
|
++++
|
+/0
|
|
CVVHFD
|
++
|
++++
|
+/0
|
|
|
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Term
| What is important regarding Peritoneal Dialysis, commonly referred to as PD? |
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Definition
- Approximately 15% of dialysis patients
- Dialyzer is the physiological peritoneal membrane
- PD patients generally have greater residual renal function, so don't use serum creatinine as a marker
- In addition to drug properties, peritoneal membrane characteristics affect drug removal (pore size, surface area, blood flow
Two Types: Automated Peritoneal Dialysis, and Continuous Ambulatory Peritoneal Dialysis |
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Term
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Definition
- Intermittent hemodialysis
- Three times a week
- Combination of diffusion and ultrafiltration/convection |
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Term
| What are the advantages of hemodialysis? |
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Definition
- Higher solute clearance
- Better defined parameters of adequacy
- Technique failure is low
- Greater correction of hemostasis
- In-center treatment allows closer monitoring of patient/treatment |
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Term
| What are the disadvantages of hemodialysis? |
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Definition
- Requires multiple visits
- Disequillibrium syndrome
- Increased rate of infection
- Greater decline of residual renal function |
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Term
| The Dialyzer is also called the filter. What characteristics make the dialyzer either high flux or high efficiency? |
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Definition
Flux:
- Large pore size
- B2-microglobulin > 20ml/min (MW 11,800)
- Fresenius FX80 (SA 1.8m2, KUF 59)
Efficiency:
- Large surface area
- B2-microglobulin >/< 20ml/min (MW 11,800)
- Fresenius F8 (SA 1.8m2, KUF 18) |
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Term
What are the different types of vascular access and their corresponding infection rates?
*Infection rates on a three-asterisk scale, three being the highest risk* |
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Definition
Venous Catheters - ***
Arteriovenous Graft - **
Arteriovenous Fistula - * |
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Term
| What is the measurement of dialysis adequacy? How do we calculate this? |
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Definition
- Measuring the efficacy of the dialysis treatment to clear toxins
- Measured by URR, or Urea Reduction Ratio
URR = Predialysis BUN - Postdialysis BUN x 100
Predialysis BUN
- Desired level of ~ 65%
- Kt/V is another parameter.
- Dialyzer clearance of urea, K, in L/h multiipled by the duration of dialysis (t) in hours, divided by the urea distribution volume of this patient (V) in liters
- Unitless parameter
- Desired of at least 1.2
- As Kt/V goes up, so does URR |
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Term
| What are the complications of dialysis and their corresponding prevalences? |
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Definition
¨Hypotension (20-30%)
¨Cramps (5-20%)
¨Nausea/Vomiting (5-15%)
¨Headache (5%)
¨Chest/Back Pain (2-5%)
¨Itching (5%)
¨Fever/Chills
¨Thrombosis
¨Infection
¨Diaylzer Reaction
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Term
What are the causes of hypotension in dialysis?
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Definition
- Hypovolemia/excessive filtration
- Antihypertensive medications prior to dialysis
- Target dry weight too low
- Autonomic dysfunction
- Low calcium and sodium dialysate
- High dialysate temperature
- Meal ingestion prior to dialysis
- Elderly and DM patients more prone to hypotension
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Term
| How can we help prevent hypotension in dialysis patients? |
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Definition
- Setting parameters for dialysis (e.g. hold ultrafiltrate for SBP <110)
- Setting goal of SBP of 150mmHg prior to dialysis
- Accurately set dry weight
- Proper Calcium and Sodium levels in dialysate
- Avoid meals prior to or during dialysis
- Use cool dialysate |
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Term
| What is the best way in which to treat hypotension in dialysis? |
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Definition
- Place in Trendelenburg position
- Decrease ultrafiltration rate
- Fluids: 100-200ml of normal saline, hypertonic saline over 3-5 minutes
- Mannitol (12.5g)
- Midodrine (alpha-1 agonist) 2.5-10mg orally 30 minutes before HD |
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Term
| What is the best way in which to prevent thrombosis in an HD patient? |
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Definition
¨Forced saline flush
¨Mechanical Thrombectomy
¨Catheter stripping
¨Exchange of catheter over guide wire
¨Alteplase: 2mg/2mL per port; aspirate after 30min, Repeat after 120min if function not restored
¨Reteplase: Instill 0.5 units/2mL per port |
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Term
| What is the best way in which to prevent infection in an HD patient? |
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Definition
¨Minimizing use/duration access
¨Proper disinfection
¨Sterile technique
¨Nasal carriage Staph eradication
¨ Unit protocols for universal precautions
¡Universal precautions
¡Limit manipulation of catheter
¡Disinfectants: povidone-iodine
¡Use of face masks by patient and caregiver |
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Term
| What is the best way to TREAT an infection in an HD patient? |
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Definition
Tunneled Cuffed Catheters:
¨Localized to exit site
¡No drainage- topical treatment (mupirocin, polysporin)
¡Drainage-gram (+) treatment (e.g. cefazolin)
¨Bacteremia: +/- signs and symptoms
¡Gram(+) treatment-cefazolin (susceptibilities)
¡Greater than 36 hours symptomatic remove catheter
¡No signs/symptoms replace catheter continue to treat for at least 3 weeks
AV Graft:
¨Local Infection: Empiric gram +/- plus Enteroccous (gentamicin + vancomycin)
¨Extensive Infection: as above +total resection
¨Access < 1 month old: treat and remove
AV Fistula:
¨Treat as subacute bacterial endocarditis for 6 weeks
¨Empiric for gram (+)
úVancomycin IV 20mg/kg LD (therapeutic monitoring)
úCefazolin IV 20mg/kg 3 times/week
¨Add gram (–) for immunosuppressed
úHIV, DM, Prostethic Valves, Chemotherapy
úGentamicin 2mg/kg IV (therapeutic monitoring)
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