Renal replacement therapy

RRT

1. Dr.MANOJ PRABHAKAR Resident , Dept. of Paediatrics RENAL REPLACEMENT THERAPY

2. DEFINITION Renal replacement therapy is a therapy that replaces the normal blood filtering functioning of the kidneys. It is used when the kidneys are not functioning well i.e in conditions like Acute or Chronic Kidney Disease.

3. MODALITIES OF RRT HEMODIALYSIS PERITONEAL DIALYSIS RENAL TRANSPLANTATION

4. DIALYSIS All dialyses modalities can be used to ensure equivalent solute clearence and ultrafiltration . Choice of procedure depends on Age & size of the patient Cardiovascular status Availability of vascular status Integrity of peritoneal membrane and abdominal cavity. Expertise available.

5. Indications of Dialysis in AKI Uremia Hyperkalemia Hyponatremia Fluid overload Metabolic Acidosis Hypercatabolic state

6. Indications in CKD GFR <15ml/min/1.73m2 BSA. Growth Failure Severe HTN Intractable intravascular volume overload Profound electrolyte abnormalities { hyperkalemia , hyperphosphatemia etc.}

7. ACUTE PERITONEAL DIALYSIS ULTRAFILTRATION : Exchange of solutes and movement of fluid across the semipermeable peritoneal membrane. DIFFUSIVE TRANSPORT : Solutes are exchanged across their concentration gradient between the peritoneal capillaries and the dialysis solution that is instilled into the peritoneal cavity.

8. Peritoneal Dialysis Catheters The most widely used is the POLYURETHANE TROCAR CATHETER which is available is many sizes.

9. Chronic dialysis catheter

10. Peritoneal Dialysis Solutions Conventionally PD solutions contain dextrose as the osmotic agent. Non – dextrose containing solutions : reduce risk of hyperglycemia Other solutes comercially available : lactate, sodium & calsium .

11. Complications Bleeding after catheter insertion Perforation of gut. Abdominal pain Leakage around catheter Difficult Drainage Exit site infections. Peritonitis Metabolic problems ( Hypo or hypernatremia , hypokalemia,hyperglycemia , hypopsosphatemia & metabolic alkalosis.

12. Chronic Peritoneal Dialysis Accepted mode of treatment for patients awaiting renal transplantation. Two types : CAPD ( Continuous Ambulatory Peritoneal Dialysis ) Contains of Plastic bag containing dialysis fluid Transfer set Permanent Peritoneal Catheter

13. This procedure is particularly suitable for infants and for small children. Complications: Peritonitis (most important complication of CAPD) Catheter malfunction Abdominal wall hernia Back pain Hydrothorax Respiratory difficulty

14. 2) CCPD ( Continuous Cycling Peritoneal Dialysis) : Most common approach involves frequent continuous ‘cycling’ of dialysate during the night, while the child is asleep & then leaving in a small volume of dialysate during the daytime. The automated device minimizes the need for extensive manual manipulation and hence reduces the risk of peritonitis. The patient can carry out day to day activities and attend school.

15.   Advantages Ability to perform dialysis at home. Technically easy than hemodialysis , especially in infants Ability to live a greater distance from medical center Freedom to attend school Less restrictive diet Less expensive than hemodialysis

16. Disadvantages  Catheter malfunction Catheter related infections Impaired appetite Negative body image

17. - HEMODIALYSIS - Provides an excellent extracorporeal mode for renal replacement. Advances in technical aspects and availability of pediatric size dialyzers have made it possible to offer hemodialysis to children in end stage renal disease.

18. Principles The basic principles of HD are the same as for PD :- A) Ultrafiltration B) Solute Removal ( by connective transport and diffuse transport)

19. What differentiates HD from PD is : The driving force between the two processes Technical aspects of the procedure Duration/Frequency of the treatments.

20. MECHANISM

21. The rate of transfer of substances depend upon : The surface area and the permeability of the dialyzer membrane The solute concentration gadient Rates of blood flow and dialysate flow Composition of dialysate .

22. Vascular Accesss : Tunneled cuffed catheter Arteriovenous (AV) fistula AV graft.

23. 1) Catheters Percutaneous temporary dual lumen catheter Cuffed central venous catheter ( Permacath ) 2) Fistulas include the Radiocephalic and Brachiocephalic fistula. 3)AV Grafts Similar to fistulae except that an artifical graft made of Teflon is used to join artery and vein.

24. Dialyzers and Blood Tubing Most dialyzers currently are hollow fiber dialyzers. Most modern dialyzers are made of modified cellulose or entirely made of synthetic material. (Advantage of being more permeable and efficient solute removal. The choice of dialyzer is based on the size of the dialyzer.

25. Length & Frequency of Dialysis The aim is for 30% reduction in BUN during the 1s dialysis(1.5-2hrs). 50% during the 2 nd treatment. (3hrs) >70% reduction during subsequent treatments (3.5-4hrs).

26. Complicaions during Hemodialysis 1.Dialysis disequilibrium syndrome: Manifested as seizures 2.Muscle Cramps 3.Hypotension. 4. Nausea & Vomiting 5.I tching.

27.   Advantages    Maximum solute clearance Best tx for severe hyper- K+ Ready availability Limited anti-coagulation time Bedside vascular access 

28.   Disadvantages Hemodynamic instability Hypoxemia Rapid fluid + solute shifts Complex equipment Specialized personnel Difficult in small infants

29. CONTINUOUS RENAL REPLACEMENT THERAPY Variant of HD therapies that are continuous and prolonged.(for days to weeks). 2 types : CVVH (Continuous venovenous Hemofiltration ) Only convective transport without adding dialytic compound.

30. b ) CVVHD (Continuous venovenous hemofiltartion dialysis) Dialytic compound added. The choice of CVVH or CVVHD is center dependent and also on the need for solute removal , which is usually greater with CVVHD.

31. Indications for CRRT Modality of choice in patients who are critically ill and hemodynamically unstable patients. Neonates and infants with cardiovascular or abdominal surgery. Trauma Shock & multi-system failure. Children with inborn errors of metabolism such as urea cycle disorders

32. Disadvantages of CRRT Same as seen in Hemodialysis . Continous nature – risk greatly multiplied. Continuous vascular access, very close monitoring – very expensive