Renal replacement in children
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Renal replacement in children
- 1. Renal replacement therapy in children Dr. Lokesh R pediatrics
- 2. RENAL REPLACEMENT • DEFINITION • MODALITIES • INDICATIONS- AKI / ESRD • PERITONEAL DIALYSIS • HEMODIALYSIS
- 3. DEFINITION Renal replacement therapy is a procedure which help to clear accumulated solutes, water or toxins from the blood by diffusion or convection or both across a semipermeable membrane. Renal failure important and independent factor determines outcome in critically ill children-morbidity and mortality
- 4. MODALITIES OF RRT • Peritoneal dialysis • Intermittent Hemodialysis (IHD) • Continuous renal replacement (CRRT) • Renal transplantation – best for ESRD – Decision of modality determined by size of pt, duration , abdominal pathology,catabolic rate, hemodynamic stability, vascular access and whether primary goal is fluid or solute removal, resources availability
- 5. Indications for Dialysis 1. In Acute renal failure: Inadequate response to conservative management • A : Acidosis metabolic (pH < 7.2) • E : Electrolytes -- Hyperkalemia (K >6.5 meq/L) or rapidly rising K, 5.5-6.5 with EEC changes), • I : Ingestion - toxins and drugs • O : Overload of fluid – symptomatic >15-20% • U : Uremia - pericarditis, encephalopathy, bleeding
- 6. Indications for Dialysis 2. In chronic renal failure: GFR= <15 ml/min/1.73 m2 body surface area Severe hypertension. Intractable intravascular volume overload Profound electrolyte abnormalities: hyperkalemia or hyperphosphatemia.
- 7. Dialysis- principles 1. Diffusion 2. Convection Dialysis = diffusion = passive movement of solutes across a semi-permeable membrane down concentration gradient – small molecules
- 8. Dialysis- principles Hemfiltration = convection = solute + fluid removal across semi-permeable membrane down a pressure gradient (solvent drag)-hydrostatic pressure / osmotic pressure fluid ,small and medium-size
- 9. PERITONEAL DIALYSIS PD catheters • Polyurethane trocar catheter: infant, pediatric and adult sizes. • Most commonly used PD catheter: silastic Tenckhoff catheter
- 10. Hard catheter • Hard catheter
- 11. PD solutions Potassium:3- 4 meq/l Heparin 500- 1000U/L DEXTROSE—OSMOTIC GRADIENT, HIGH DEX- HYPERGLYCEMIA, PEROTONITIS. ALT- ICODEXTRIN
- 12. Preparation of dialysate • Solution A: 440 ml 5% dextrose + 60 ml sodium bicarbonate • Solution B: 500 ml normal saline • 500 ml solution B +250 ml solution A, • Sodium : 140 mEq/l, • Bicarbonate: 40 mEq/l • Dextrose : 1.5 g/dl • IV calcium:precipitate if added to a bicarbonate containing fluid.
- 13. Insertion of the Catheter 1. Empty the bladder 2. Surgically drape the abdomen. 3. Anesthetize the skin and subcutaneous tissue in the midline at 1/3rd of the distance from the umbilicus to the public symphysis. In young infants, it may be preferable to insert the catheter in the left flank. 4. Insert a gauge 16 or 18 ‘intracath’ at the above point into the peritoneal cavity and infuse 20 to 40 ml/kg of warmed dialysate over a period of 5 to 10 minutes to distend the abdomen and facilitate catheter insertion.
- 14. 5.Remove the ‘intracath’ and prepare the PD catheter. Insert the stylet into the catheter and note the black markings indicating the direction of the curve of the tip, which should face the pubic symphysis. 6. Puncture the abdominal skin with a No. 15 blade held vertically. 7. Insert the PD catheter with the stylet using a gentle ‘boring’ motion. Entry into the peritoneal cavity is indicated by a sudden decrease in resistance & gush of dialysis fluid into the catheter.
- 15. 8. Attach the right-angled end of the connecting set to the catheter and run in dialysis fluid, which should flow in a continuous stream. 9. About half the dialysate is allowed to rapidly run out by gravity drainage. 10. The inflow is then started. 11. Strict asepsis must be maintained throughout the procedure.
- 16. • Optimal fill volume of dialysate for each exchange : 1100-1200 ml/m2 BSA • 30-50 ml/kg/body weight. • The fill volume should not exceed a maximum of 2 l.
- 17. • Acute PD can be performed either manually or by a machine. • 3 phases, • Fill time = 5-10 minutes • Dwell time =30-45 minutes • Drain time = 5-10 minutes • Total cycle = 60 minutes.
- 18. • Dialysis is continued till • Correction of fluid & electrolyte disturbances • Acidosis is corrected, • Blood urea level is reduced • Renal function starts recovering. Once the last exchange is over, the dialysate is drained out completely and the catheter is removed.
- 19. Monitoring • BP & HR • Intake & output. • Weight at least once daily • Blood levels :Urea, creatinine, electrolytes & sugar should be measured daily or more frequently. • Peritoneal fluid should be examined periodically to detect peritonitis
- 20. Complications • Bleeding after catheter insertion • Perforation of gut • Abdominal pain • Leakage around catheter • Difficult drainage • Pulmonary complications • Exit site infections • Peritonitis • Metabolic problems
- 21. CHRONIC PERITONEAL DIALYSIS • Accepted mode of treatment for patients awaiting renal transplantation. Chronic dialysis: 2 types • CAPD (chronic ambulatory peritoneal dialysis) performed manually • CCPD (continuous cycling peritoneal dialysis) automated device
- 22. CAPD system • Plastic bag containing dialysis fluid • Transfer set. • Permanent peritoneal catheter
- 23. Dialysis Prescription • 4-6 daily exchanges are carried out while the child is awake (every 4-6 hour). • Goal volume of 1100-1200 ml/1.73 m2/cycle.
- 24. Advantages: • Continuous removal of solute & water. • Avoids rapid fluid & solute shifts. • Hypertension & anemia better controlled. • Particularly suitable for infants & small children. Disadvantage: • Peritonitis • Abdominal wall hernia, • Hydrothorax • Respiratory difficulty • Protein & amino acids loss. • Hypogammaglobulinemi a • Diabetes, obesity and hyperlipidemia
- 25. Automated Peritoneal Dialysis (APD) • Cycler is used to help in the delivery and drainage of dialysate. • Cycling of dialysate during the night while the child is asleep. • Small volume of dialysate allowed to dwell during the daytime while the child carries out his/her normal activities.
- 26. Dialysis prescription • Total of about 10 hours of exchanges during the night (6 cycles, each about 1.5 hr in duration)
- 27. Advantages • Reduces the risk of peritonitis • Better metabolic control • Freedom to the child during the daytime.
- 28. INTERMITTENT HEMODIALYSIS • Rapid ultrafiltration and solute removal • Accurate & precise volume removal. • Ultrafiltration & solute removal can be isolated from each other and independently controlled.
- 29. Click to add title Basic principles of HD • Ultrafiltration • Solute removal • Convective transport • Diffusive transport Dialyser - polysulfone Dialyser - polysulfone
- 30. Hemodialysis • Dialysis occurs when blood and dialysate are made to interface across an artificial semi-permeable membrane (the dialyzer) outside the body. • The driving force behind ultrafiltration is the hydrostatic pressure gradient across the dialyzer that the HD machine generates using a pump.
- 31. In HDIn HD
- 33. Vascular Access Short term IHD: • Femoral , subclavian or internal jugular(IJ) veins. Long -term IHD • Central venous catheter • Arteriovenous (AV) fistulae
- 34. Dialyzers and Blood Tubing • Extracorporeal blood not exceed 10-15% of the blood volume. • Surface area of the dialyzer =75-100% BSA of the child.
- 35. Dialysis Prescription • Dialyzer and blood tubing. • Duration of dialysis= 3-4 hours per session, • Frequecy = 3/week (every other day). • Infants & small children may require daily dialysis.
- 36. Difficulties During Dialysis 1.Dialysis disequilibrium syndrome: Manifested as seizures. • Rapid solute removal with a resultant fall in plasma osmolality. • First few cycles. • Associated with very high BUN. Prevention • Continuous mannitol infusion at 0.5 to 1 g/kg. • Dialysis using low blood flow rates.
- 37. 2. Hypotension. Prevention • Rapid infusion of low volumes (50-100 ml) of normal saline or albumin • Temporarily stopping ultrafiltration.
- 38. Disadvantages • Hemodynamic instability due to rapid fluid shifts induced by volume removal and osmotic changes relating from rapid correction of azotemia, • Need for systemic anticoagulation and the risk of bleeding, • Technical challenges in using it in smaller children.
- 39. CONTINUOUS RENAL REPLACEMENT THERAPY • HD therapies done for days to weeks. • Continuous & prolonged without interruption. Advantages • Less rapid osmotic shifts. • Hemodynamic stability much better than IHD. Modality of choice: • Critically ill & hemodynamically unstable. • Patients on vasoactive infusions for sepsis or cardiogenic shock.
- 40. CRRT Modalities 1. CVVH- Continuous Veno-Venous Hemofiltration 1. Convection 2. CVVHD- Continuous Veno-Venous Hemodialysis 1. Diffusion 3. CVVHDF- Continuous Veno-Venous Hemodiafiltration 1. Diffusion and Convection • Blood from the patient is removed from the venous circulation and returned back into the venous system
- 41. Indications for CRRT • Critically ill, hemodynamically unstable patients • Neonates & infants with cardiovascular or abdominal surgery, trauma with shock and multisystem failure. • Removes inflammatory cytokines • Rapid generation of toxic metabolites: • Inborn error of metabolism • Tumor lysis syndrome.
- 42. Dialysis Prescription • Starting net ultrafiltration rate is 0-1 mg/kg body weight per hour. • Hourly basis calculation is done of all the fluids given. • Dialysate flow rates are much slower:2000 ml/1.73 m2 BSA/hour.
- 43. Disadvantages of CRRT • Hypomagnesemic & hypophosphatemic. • Continuous & prolonged anticoagulation • Technically more challenging.
- 44. Advantages and disadvantages of various modalities of renal replacement therapy
- 45. Nutritional Management • 100 to 110% of RDA for calories & protein. • Daily protein intake: S albumin>3g/dl • Infants & children < 3 years =2.5-3 g/kg, • 3 to 12 years = 2.0-2.5 g/kg • Postpubertal children = 1-1.5 g/kg • Vitamins and micronutrients • Other medications: • erythropoietin, • Iron • Vitamin D
- 46. TAKE HOME MESSAGE • In children with renal failure RRT – important and independent determinant of outcome • Newborn and young children – PD clear advantage over hemodialysis • Hard PD catheter left maximum of 72 hours • With the availability of HD one can control ultrafiltrate or solute removal independently, accurately • Renal transplant is the Best RRT for ESRD
- 47. References 1. Pediatric nephrology-Avner. 5th edition. 2. Pediatric nephrology- Arvind Bagga 5th edition 3. Nelson textbook of pediatrics- 19th edition. 4. Uptodate.com 5. Acute renal replacement therapy in pediatrics-International Journal of Nephrology
- 48. Thank you
- 49. Hemodialysis Advantages • Maximum solute clearance • Best tx for severe hyper- K+ • Ready availability • Limited anti-coagulation time • Bedside vascular access Disadvantages • Hemodynamic instability • Hypoxemia • Rapid fluid + solute shifts • Complex equipment • Specialized personnel • Difficult in small infants
- 50. Peritoneal dialysis Advantages • Simple to set up + perform • Easy to use in infants • Hemodynamic stability • No anti-coagulation • Bedside peritoneal access Disadvantages • Unreliable ultrafiltration • Slow fluid + solute removal • Drainage failure, leakage • Catheter obstruction • Respiratory compromise • Hyperglycemia • Peritonitis
- 51. CVVH Advantages • Easy to use in PICU • Rapid electrolyte correction • Excellent solute clearances • Rapid acid/base correction • Controllable fluid balance • Tolerated by unstable patients • Early use of TPN • Bedside vascular access routine Disadvantages • Systemic anticoagulation * • Citrate anticoagulation new • Frequent filter clotting • Hypotension in small infants • Vascular access in infants
Editor's Notes
- RRT is a procedure which help to clear accumulated solutes or toxins from the blood by diffusion or convection across a semipermeable membrane.
- Diffusion- rate of transfer depends on 1. menbrane permeablility( number and size of pores) 2. solute size and charge 3. membrane surface area. 4. magnitude of concentration gradient. Solute transfer directly proportional to membrane surface area and concentra gradient and inversely proportional to particle size. Convective transport- solute movt scross the SPM independent of conc gradient. Main determinant of solute drag is the osmotic gradient achieved by the amt of plasma water pushed across the membrane ( ultrafiltrate)
- Conventionally PD solutions contain dextrose as the osmotic agent. Non-dextrose containing solutions reduce the risks of hyperglycemia and sclerosis of the peritoneal membrane with long-term exposure to glucose. These include icodextrin. Potassium should be added to the dialysate in physiologic concentrations (3-4 mEq/l) if the child has a normal serum potassium. Heparin (500 – 1000 U/l), added to the dialysate in children with acute renal failure, prevents clotting of the catheter with fibrin/blood.
- For acute dialysis the starting fill volume for the first several days should be much lower (typically one-half of the ‘goal’ fill volume). In patients who may be experiencing respiratory compromise or who are at risk for that (such as after cardiac surgery),the fill volume should be even lower (one-fourth of the ‘goal’ fill volume). This also reduces the risk of leaks and of patient discomfort.
- Dwell times any shorter than 30 minutes preclude adequate exchange of solutes and fluid, and are not recommended. Dwell times longer than 45 minutes (upto 2 hour) may be used if critical fluid overload or hyperkalemia are not present.
- 4-6 daily exchanges are carried out at about equal intervals while the child is awake (every 4-6 hour).
- CAPD produces a more continuous removal of solute and water leading to a steady state biochemical and fluid status, avoiding the rapid fluid and solute shifts that occur during hemodialysis. Connection between the bag & the transfer set is broken 3 to 5 times/day. Protein and amino acids lost in the dialysate outflow (much more during peritonitis) should be adequately replaced. Loss of immunoglobulins may also occur occasionally leading to overt hypogammaglobulinemia. Continued absorption of glucose from the dialysis fluid may lead to diabetes, obesity and hyperlipidemia
- ‘cycling’ of dialysate during the night, while the child is asleep, and then leaving in a small volume of dialysate (usually half the fill volume of each nightly cycle) during the daytime while the child carries out his/her normal activities, to allow ongoing diffusive transport. This is referred to as continuous cycling peritoneal dialysis (CCPD).
- After the last cycle, the abdomen is refilled with ‘fresh’ dialysate and the child is disconnected from the cycler.
- Blood is drawn via a vascular access device at a minimal flow rate of about 3-5 ml/kg/min and up to 10 ml/kg/min (blood flow rates in adult sized patients 200-400 ml/min) and passes through a set of tubes into a blood pump which generates a positive pressure and forces the blood into the dialyzer. In order to prevent clotting of the blood within the dialysis circuit, heparin is infused into the circuit. Alternatives to heparin include citrate, novel agents such as argatroban, or using no anticoagulation and flushing the circuit frequently with saline (in patients who are coagulopathic or profoundly thrombocytopenic). The blood enters into one side of the semipermeable membrane of the dialyzer. On the other side of the membrane, dialysate with varying concentrations of electrolytes (manipulated based on the patient’s electrolytes) mixed in with pretreated water flows in the opposite direction (countercurrent dialysis) at a rate of 500 ml/min (usual range 300-500 ml/minute). During this process, ultrafiltration and solute removal occur and the ‘purified’ blood is then returned to the patient’s circulatio
- A consideration while choosing dialyzers and blood tubing is that at no time should the extracorporeal blood volume (i.e. the blood volume in the dialyzer and blood tubing) exceed 10-15% of the blood volume (approximately 70-80 ml/kg body weight), otherwise hemodynamic instability might ensue. If the smallest available dialyzer and tubing combination still has a priming volume that exceeds 15% of the child’s blood volume, the circuit may need to be ‘primed’ with colloid, preferably blood, rather than the usual normal saline prime, so that as the patient’s blood is being drawn into the dialyzer, the blood priming in the dialyzer circuit is simultaneously going back into the child.
- includes the choice of dialyzer and blood tubing, theblood and dialysate flow rates, and the total volume of fluid to be removed (theultrafiltration volume) all of
- Rapid solute removal with a resultant fall in plasma osmolality may result in the ‘dialysis disequilibrium’ syndrome manifested by seizures during or immediately after dialysis. This is most often seen during the first few treatments in children who are starting IHD with very high blood urea nitrogen concentrations. Disequilibrium can be prevented by the infusion of mannitol at 0.5 to 1 g/kg as a continuous infusion during the first 1-2 hours of dialysis in children with very high urea nitrogen levels;
- with rapid infusion of low volumes (50-100 ml) of normal saline or albumin and by (temporarily) stopping ultrafiltration; if hypotension
- Continuous renal replacement therapy (CRRT) is the term given to HD therapies that are continuous and prolonged () without interruption, in contrast to the above described intermittent and brief HD treatments that are conventionally used for patients with AKI and ESRD.
- If only convective transport is felt to be sufficient, without the need for adding countercurrent dialysis, the procedure is referred to as CVVH (continuous venovenous hemofiltration). If a dialytic component is added, the technique becomes CVVHD (continuous venovenous hemofiltration-dialysis). CVVH- modality requires replacement solution. This replacement solution drives convection. CVVHD- is continuous form of hemodialysis and requires dialysate solution to create a concentration gradient for diffusion. CVVHDF- hemodiafiltration requires the use of dialysate and replacement solution and uses both transport mechanisms of convection and diffusion.
- Due to the continuous nature of CRRT, children often become hypomagnesemic and hypophosphatemic, which is rare with IHD.
- Children should receive 100 to 110% of the recommended daily allowances for calories and protein. The daily protein intake for infants and children below 3 years should be 2.5-3 g/kg, between 3 to 12 years 2.0-2.5 g/kg and for postpubertal children between 1-1.5 g/kg. Supplements of water soluble vitamins and micronutrients should also be provided. The oral intake of infants and toddlers may not be sufficient and nasogastric or gastrostomy feeding are often necessary. Serum albumin level is a good indicator of protein balance and inflammation and a level above 3 g/dl should be maintained to ensure a good quality of life. Other medications almost always needed in children on IHD include erythropoietin, iron (often IV iron), and vitamin D.