IHD vs CRRT vs SLED
OVERVIEW
Continuous renal replacement therapy (CRRT) is the modality most widely used in Australia and New Zealand ICUs. There is no evidence suggesting mortality benefit for one modality over another (Cochrane Systemic Review)
Abbreviations:
- IHD = intermittent haemodialysis
- CRRT = continuous renal replacement therapy
- SLED = sustained low-efficiency dialysis or SLEDD = sustained low-efficiency daily dialysis
- VD = volume of distribution
PROS AND CONS OF DIFFERENT MODALITIES
COMPARE AND CONTRAST DIFFERENT MODALITIES
| 1 | 2 | 3 | 4 |
|---|---|---|---|
IHD | SLEDD | CRRT | |
| Name | Intermittent hemodialysis | Slow (or sustained) low efficiency daily dialysis | Continuous renal replacement therapy |
| Mechanism and molecules removed | Dialysis – mostly low MWt | Small + middle molecules with SLEDD/F | Small + middle molecules with CVVHDF |
| Use |
|
|
|
| Blood flow | 300 - 400 mL/min | 100 - 150 mL/min | 150 - 200 mL/min |
| Dialysate flow |
|
|
|
| Efficiency | High | Moderate | Low (but increased clearance of high VD molecules over time) |
| Urea clearance (mL/min) | 150 | 80 | 30 (CVVHDF) |
| Hemodynamic stability | Poor (hypotension common) | Good | Good |
| Duration | 3-4 h 3x/week | 6-12 h daily | Continuous (24h/filter) |
| Access | Fistula or vascath (must be good!) | Fistula or vascath (must be good!) | Vascath only |
| Anticoagulation | Not needed | Usually not needed (if filter clots can lose ~150 mL blood) | Important (if filter clots can lose ~150 mL blood) |
| Dialysis Dysequilibrium Syndrome (DDS) | Insufficient time for equilibration between compartments can cause cerebral edema | N/A | N/A |
| Drugs and toxicology | Risk of rebound if high VD. Better for low VD (e.g. toxic alcohols) | Unclear effects on drug pharmacokinetics | Slower removal |
| Logistics | Need tap water supply, need hygienic effluent removal, Technically difficult | High start up costs, low familiarity, low running costs, Hypophosphatemia | High workload, clearance limited by interruptions, costly sterile dialysate bags, immobility |
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC