Dialysis Flashcards
What is dialysis?
removal of waste products
By what mechanism does dialysis work?
Diffusion
What does “CKD5D” mean?
Someone whose GFR is <15 ml/min that is on dialysis
What does “CKD5ND” mean?
Someone whose GFR is <15 ml/min who is not on dialysis.
What is ESRD
End stage renal disease
Requirement for dialysis
ESRD w/ >3 months needed to sustain life.
Methods/Mechanisms of drug removal during dialysis
Diffusion
Convection - ultrafiltration
Dialysis Modalities/ Types of Dialysis
-Hemodialysis
-Peritoneal dialysis
-Continuous kidney replacement therapy (CKRT)
Direction of fresh dialysate
top - bottom
Direction of clean blood
bottom to top
Hemodialysis access points
Arteriovenous fistula
Arteriovenous graft
Central venous catheter
HD Access w/ highest risk of infection and thrombosis
Central venous catheter
HD Access w/ lowest risk of infection and thrombosis
Arteriovenous fistula
How long does arteriovenous fistula take to mature
3 months
Preferred HD Access
Arteriovenous fistula
Types of peritoneal dialysis
CAPD: continuous ambulatory peritoneal dialysis
APD: Automated peritoneal dialysis (nighttime)
Peritoneal Access
Catheter
What is Continuous kidney replacement therapy?
A “slow hemodialysis” for critically ill pts w/ unstable hemodynamics
CKRT Modalities
- CVVH
- CVVHD
- CVVHDF
Which clearance mechanism is better for large solutes?
Convection
Drug factors influencing dialysis drug removal
- Molecular weight
- Protein binding
- Volume of distribution/Lipophilicity
Patient factors influencing dialysis drug removal
- Albumin
- Fluid status
- Blood pressure
Drug removal is increased by
Small molecular weight
Low protein binding
Small Vd/lipophilicity
High flux hemodialysis
Semi-synthetic/synthetic dialysis membranes
What to do prior hemodialysis? (Dosing)
- Hold AntiHTN drugs
- Therapeutic dose monitoring
What to do during hemodialysis? (Dosing)
Give intra-dialytic meds:
- ESA’s
- Active Vitamin D
What to do after hemodialysis? (Dosing)
- Supplemental doses of drugs removed
- Administer meds significantly removed eg ABx
What drugs need a supplemental dosing
Drugs removed >30 - 40%
How much supplemental dose needed? (Equation)
Normal dose x fraction removed by HD
CrCl IN CKRT
Assume 20 - 25 ml/min
**difficult to predict drug removal
**use drug literature
Complications of drug dosing
Hypotension
Cramping
Fatigue
Infection***
Thrombosis
Bleeding
***#2 cause of mortality in HD
Causes of hypotension w/ Hemodialysis
- Hypovolemia
- excessive fluid removal
- antiHTN admin prior to HD
- autonomic dysfunction
How to prevent hypotension w/ HD
- Select the appropriate dry weight
- Hold the antiHTN meds
How to manage hypotension w/ HD
- Small fluid bolus 100 - 250 ml 0.9% NaCl
- Decrease fluid removal (ultrafiltration)
- Midodrine
Midodrine MOA
alpha 1 agonist pro drug for peripheral vasoconstriction
Midodrine dosing
2.5 - 10 mg PO 30 mins before HD
Midodrine Adverse Effects
bradycardia, hypertension (???), peripheral ischemia, urinary retention
Midodrine DDIs
- MAOi’s
- sympathetic activating drugs
Causes of cramping w/ Hemodialysis
- hypovolemia
- decreased muscle perfusion
How to prevent cramping w/ Hemodialysis
Selection of appropriate dry weight
How to manage cramping w/ Hemodialysis
- small fluid bolus 0.9% NaCl
- decrease fluid removal
- Vitamin E 400 IU PO QHS
***NEVER GIVE QUININE (FDA WARNING)
Site of infection in Hemodialysis
Bloodstream leading to pneumonia
2 leading cause of death in Hemodialysis?
Infection
How to treat MRSA?
Vancomycin
What type of ABx to use in dialysis infections?
Broad spectrum gram +ve or -ve ABx’s
Causes of Thrombosis w/ Hemodialyis
Virchow’s Triad
- use of ESA’S
How to prevent thrombosis w/ Hemdialysis
Heparin w/ dialysis
***Risk of HIT
How to manage thrombosis w/ Hemodialysis
Alteplase (Cathflo) 2mg/2ml for 30 -120 mins
Complications of Peritoneal Dialysis
- Peritonitis
- Fluid Overload
- Hyperglycemia
Vancomycin in ESRD