Block 4: Dialysis Flashcards
What are the treatment options for ESRD?
- HD
- Peritoneal dialysis
- Kidney transplantation
What is ESRD?
eGFR <15 mL/min/1.73 m2 for at least 3 months or need chronic dialysis
What are the types of dialysis?
- Chronic vs Acute
- Intermittent Hemodialysis (IHD)
- Peritoneal Dialysis (PD)
- Continuous Renal
- Replacement Therapy (CRRT)
How does dialysis impact the quality of life?
- TIW sessions for 3-5 hr
- Complications
- Fatigue and fear of unknown related to disease
When do you begin planning for dialysis?
eGFR <30mL/min
When should an individual receive surgery for dialysis?
- eGFR <25 mL/min
- Scr > 4 mg/dL
- 1 year prior to anticipated need
When should you initiate dialysis?
- s/s of kidney failure (eg, serositis, acid-base or electrolyte abnormalities, pruritis)
- Inability to control volume/BP
- progressive deterioration in nutritional status or cognitive impairment
- eGFR ~ 5 to 10 mL/min/1.73 m2
What are the indications of HD?
Acidosis
Electrolytes (refractory hyperK >6.5)
Intoxications
Overload with fluid refractory to diuresis
Uremic pericarditis, uremic encephalopathy
What are the dialyzable drugs?
INH, isopropyl alcohol
Salicyclates
Theophylline
Uremia
Methanol
Barbiturates
Lithium
Ethylene glycol
Dabigatran, divalproex
What is the principle of dialysis?
Substances movefrom the blood—> dialysate by either passivediffusion or ultrafiltration/convection
What does the rate of diffusion depend on?
- concentration gradient
- solute characteristics (ie, size, watersolubility, and charge)
- blood and dialysate flow rates
- dialyzer membranecomposition/thickness/porosity
What is the importance of ultrafiltration?
Hydrostatic pressure to remove excess of fluid
What is the importance of convection?
Dragging dissolved solute across the membrane during ultrafiltration
Describe the mechanism of hemodialysis and how it works?
What are the advantages of HD?
- Higher solute clearance allows intermittent treatment
- Parameters of adequacy of dialysis are better defined and therefore under dialysis can be detected early
- Technique failure rate is low
- Intermittent heparinization is required, hemostasis parameters are better corrected with hemodialysis than peritoneal dialysis
- In center HD enables closer monitoring of the patient
What are the disadvantages of HD?
What are ADRs of HD?
- Hypotension
- Cramps
- NV/HA
- Chest pain
- Back pain
- Fever and chills
What are the complications of HD?
- Hemodynamic variability
- Thrombosis
- Infection (leading cause of mortality)
How do you prevent thrombosis of HD?
Catheter lock solution of UFH, TPA, Sodium citrate
What are are the TPA?
Alteplase, relteplase, tenecteplase
How is sodium citrate used as a thrombin prevention treatment?
Causes less bleeding vs heparin (Preferred CRRT)
How is the treatment of thrombosis caused by HD?
Saline flush and TPA
How can hypotension complicate HD?
↓ ultrafiltration rate and dialysate temp or admin NS
How do you counsel patients on HD with hypotension?
- Take BP med post HD
- Limit sodium, limit interdialytic weight gain → ↓ volume and rate of fluid removal
What is the treatment of autonomic dysfunction with HD patients with hypotension?
- Midodrine 2.5 -10 mg PO 30 min prior to HD (titrating 2.5 or 5 mg ): Alpha-a agonist
- Droxidopa 100 -600 mg PO 1 hr prior to HD (titrating, start with 100 mg): Active metabolite - norepinephrine
How do you prevent cramping from HD?
Avoid hypotension
How do can you use HD with HTN patients?
Dialyzable: metoprolol, atenolol, ACEi
Consider only if HTN: ARB, carvedilol, Amlodipine (Caution on hypotension)
How do you prevent infection from HD?
Topical agents at access site
Use of PPE by HCPs
What are topical agents for infection prevention?
- Iodine
- Mupirocin
- Chlohexidine
- Triple antibiotics
How do you treat infection of HD induced infection?
- Systemic and local antibiotics
- Potential removal or replacement of catheters
What is PD?
How does PD work?
- Contiguous peritoneal membrane surrounds peritoneal cavity
- Instill 2 to 3 L of dialysate TID
- Less effective than HD
Wha is in the peritoneal cavity?
~100 mL of lipid-rich lubricating fluid capable of expanding to several liters
What is the purpose of peritoneal membrane?
semipermeable membrane, across which diffusion and ultrafiltration occur
How long does PD last?
- Each exchange lasts 4 to 6 hours, then a single dialysate exchange overnight lasting 8 to 12 hours.
- Requires aseptic manipulation and adds approximately 30 minutes/exchange
What are the advantages of PD?
What are the disadvantages of PD?
What are the mechanical complications of PD?
- kinking
- excessive catheter motion, 3. pain from the catheter tip
- pain from dialysate inflow
What are the medical complications of PD?
- Increased adipose tissue deposition
- Decreased appetite
- Malnutrition
- Altered insulin requirements/hyperglycemia
- FIbrin fomration
What are the infectious complications of PD?
- Peritonitis
- Catheter-related infections
- Average 1 infection/24-48 months
How do you prevent infection of PD?
Topical antiseptic agents at access site:
1. Iodine
2. Mupirocin
3. Chlorhexidine
Use of PPE by HCPs
How do treat infection of PD?
Intraperitoneal (IP) antibiotics > IV
1. intermittent (one exchange per day)
2. Continuous therapy (all exchanges)
What are modes of solute removal (CRRT)?
CVVH – convection
CVVHD – diffusion
CVVHDF - both
When is CRRT used?
Critically ill ICU patients
1. Less hypotensive
2. More clotting
3. Patient immobility
How characteristics of a drug qualify it to be dialyzable?
- LMW (<20,000 Da)
- Low Vd 9<2L/kg)
- High water solubility
- Low PPB (<90%)
When do we modify when making a dosage adjustment for HD/PD?
- Dose
- Frequency and interval
- Timing relative to HD/PD sessions
Always give the usual loading dose
Describe how HD, PD, and CRRT remove drugs?
HD > PD at drug removal
CRRT continuously removes drug
