Acute renal replacement therapy (RRT) is indicated for acute kidney injury (AKI) with severe complications such as hyperkalemia, acidosis, or fluid overload. Other indications include toxic ingestions that can be cleared by RRT like toxic alcohols, lithium, and salicylates. RRT may also be used to manage severe electrolyte imbalances other than from AKI, including sodium levels less than 110 or greater than 160 mmol/L, and hyperthermia over 40°C.

1. INDICATIONS FOR ACUTE RENAL
REPLACEMENT THERAPY
Jonathan Tembo 04 Nov 2014

2. Outline
• History
• Definitions
• Modes of RRT
• Indications
• Summary

3. History
• 1861 ,Thomas Graham
coins the word ’dialysis’
• In 1913, Abel, Rowntree,
et al construct first
artificial kidney.
• 1943, WJ Kolff and H Berk
, first practical human
haemodialysis machine ,
the Netherlands.
• The arteriovenous shunt,
as described by Quinton
and Scribner (1960)

4. 3-Definitions
• Hemodialysis
– Hemodialysis filter
substitutes for glomerulous
– Blood flows on one side of
semipermeable memb &
dialysate flows on other side
in counter current direction
– Electrolytes & H2O move
from blood across
Concentration gradient
– Diffusive clearance of small
molecules

5. 2-Definitions
• Hemofiltration
– Plasma forced from blood
space into effluent across
semipermeable membrane
by application of pressure
– Convective clearance of
small & middle size
molecules by solvent drag
– Serum electrolytes not
changed unless replacement
fluid infused into blood

6. 1-Definitions
• Hemodiafiltration
– Simultaneos use of both
hemofiltration & dialysis
– Convective & diffusive
clearance

7. 3 -Modes of RRT
• Intermittent
• Continuous

8. 3

9. 2- Modes-Intermittent
• Peritoneal Dialysis (PD)
• Intermittent Hemodialysis (IHD)
• Pure Ultra filtration (PUF)
• Hybrid therapies
– Sustained Low Efficiency Daily Dialysis (SLEDD)
– Sustained Low Efficiency Diafiltration (SLEDF)
– Extended Daily Dialysis (EDD)
– Slow Continuous Dialysis (SCD)

10. 1-Modes-CRRT
• Slow Continuous Ultra filtration(SCUF)
• Continuous Venovenous Hemofiltration-CVVH
• Continuous Venovenous hemodialysis-CVVHD
• Continuous Venovenous hemodiafiltration
CVVHDF

11. IHD-prescription
• Access
– temp dialysis catheter, tunneled cuffed
catheter(hickman), A-V fistula,A-V graft
• Treatment duration
• Filter size
• Blood flow rate /dialysate rate/dialysate bath
• Ultrafiltration goal
– Amt of fluid to be removed per session

12. Catheters

13. Advantages-IHD
Advantages
• Clearance per unit time
faster
–  better for life threatening
indications Hyperkalaemia,
toxicological
Complications
• Vascular access
– Thrombosis & stenosis=loss
of bruit
– Infections,Staph,Vanc
– Aneurysms,CCF,
• Hypotension

14. CRRT
Advantages
• Slower rates of solute flux &
fluid removal  better
tolerated hemodynamically
• Allows for increased net
daily ultrafiltration
• Increased clearance
Disadvantages
• Long term immobilisation of
pt
• Continuous anticoagulation
• Hypothermia
• Labour intensive 1:1 nursing

15. Indications for RRT
• Renal
• Non Renal

16. AKI
• Uraemia =Urea in blood
• Def: an abrupt (1 to 7 days) and sustained
(more than 24 hours) decrease in kidney
function.
– Accumulation of Urea & Creat
– Increased K,PO4,non volatile acids
– ± Decreased urine output

17. AKI-RIFLE Classification

18. Aetiological classification of AKI
• Pre-renal
– Adaptive response of intact nephrons to volume
depletion & / hypotension
– Azotaemia
– Urea:Creat ratio
• Renal
– Vascular
– Gn
– ATN
• Post renal

19. Indications-AKI
• Hyperkalaemia
– >6.5 mmol/L or rapidly rising
• Severe acid-base disturbance
– Uncompensated Severe metabolic acidosis pH <7.1
• Anuria
– UO <50mL/12h
– Urea >35mmol/L
– Creat >400
• APO resistant to alternative therapy
• Uraemic complications
– Encephalopathy,myopathy,neuropathy

20. Hyperkalaemia
• Excessive intake
• Increased production
• Decreased renal excretion
• Compartment shifts
• Drugs
• Factititious

21. Hyperkalaemia

23. 5-Rhabdomyolysis

24. 4-Indications- Rhabdomyolysis
• Breakdown of skeletal muscle and release of
intracellular contents
• Myalgias,weakness, dark urine(myoglobin)
• CK ≥X5
• Hyper K,
• Hyperuricaemia, Hyper PO4,Hypo Ca
• HAGMA
• AKI-myoglobinuric
• Lactic acidosis
• DIC

25. 2

26. 3-Rhabdomyolysis- Physical causes
• Trauma & compression
• Occlusion/hypoperfusion of muscular vessels
• Excessive muscle strain
– Xs,seizure,tetanus,DT
• Electrical current
• Hyperthermia
– Xs, sepsis, NMS, Malignant hyperthermia

28. Sjambok

29. 2-Rhabdomyolysis-Non Physical
• Drugs & toxins
– Statins,fibrates,ETOH,heroin,venoms
• Infections- local & systemic
• Endocrinopathies 
• Electrolyte abnormalities
• Metabolic myopathies
• Autoimmune

30. 1-Rhabdomyolysis-Treatment
• Fluid resuscitation- 0.9% NaCl
• Urine alkalinisation with HCO3
-
– pH >6.5(serum pH 7.40-7.45)
– UO 3mL/kg/hr =200mL
– Not shown to impact outcomes in humans
• Diuretics
– Mannitol ,?acetazolamide
• RRT

31. Indications Non-Renal
• Toxins
• Hyperthermia T > 40 °C
• Na <110 and >160mmol/L

32. Toxicological indications– Poison
Characteristics
• Small enough and lack charge will cross
dialysis membrane
• Highly water soluble
• Small volume of distribution (<1L/Kg)
concentrated in blood rather than tissues
• Have low protein binding
• Rapid redistribution from tissues
• Slow endogenous elimination

33. Tox -The drugs
• Toxic Alcohols
• Li
• Salicylates
• Theophylline
• K+ salt OD + Hyper K
• Phenobarb coma
• Valproate
• Carbamazepine
• Metformin lactic
acidosis

34. Indication- Acute fluid overlod

35. Complications of RRT
• Central venous access
• Electrolyte abnormalities
• Hypovolaemia
• Hypothermia
• Nutritional
– Amino acids,Vitamins,trace elements
• mm

36. Indications -Summary
• A -Acidosis (Metabolic) refractory to HC03
• E - Electrolyte imbalances- Hyper-K
• I - Ingestions toxic alcohols,Salicylates,Li,
• O - Overload, fluid
• U - Uremia

37. 1

38. References
• Polly E.Parsons,Jeanine Wiener- Kronish,Critical
Care Secrets ,5th Ed, Elsevier
Mosby,2013.pp307,548
• Linsay Murray et al, Toxicology Handbook,2nd
Ed,2011,Elsevier,pp28-29.
• Judith E.Tintinalli,Tintinalli’s Emergency
Medicine,A Comprehensive Study Guide,7th
Ed,2011,McGrawHill,pp624-630
• http://renux.dmed.ed.ac.uk/EdREN/index.html,a
ccessed 04 Dec14