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Continuous Renal Replacement Therapy
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- 2. HAEMODIALYSIS • A medicalprocedure to remove fluid and waste products from the blood and to correct electrolyte imbalances. This is accomplished using a machine and a dialyzer, also referred to as an "artificial kidney." • Hemodialysis is used to treat both acute (temporary) and chronic (permanent) failure.
- 3. Continuous Renal ReplacementTherapy (CRRT) It is an extracorporeal blood purification therapy intended to substitute for impaired renal function over an extended period of time and applied for or aimed at being applied for 24 hours a day.
- 4. DIFFERENCE BETWEEN CRRTAND CONVENTIONAL DIALYSIS • Two major dialysis techniques:conventional intermittent haemodialysis (IHD) and continuous renal replacement therapy (CRRT) • One difference between these two options is fairly evident the time during which they are applied • CRRT is, in theory, applied continuously, whereas IHD, just like chronic haemodialysis, is applied for only a few hours during the day.
- 5. Contd… • Because ofthe short treatment time, IHD needs to deliver highly efficient therapy for toxin and fluid removal • In contrast, CRRT modalities are mostly rather low-efficiency techniques, and therapy needs to be continuous in order to be adequate
- 6. HISTORY OF CRRT •Continuous Renal Replacement Therapies are also a type of haemodialysis that were born out of frustration on the part of intensive care medical practitioners due to the restrictions of peritoneal dialysis and the delays to the commencement of IHD.
- 7. • Peritoneal Dialysishas been shown to have restricted clearance of wastes and fluids, the risk of the introduction of infections, limiting respiratory and cardiac function as well as making blood glucose levels difficult to manage. • Therefore peritoneal dialysis is not recommended for treating adults in the intensive care unit
- 8. • Normal IHDtreatment consisted of 4 hours of treatment every second day and due to haemodialysis machines requiring specialised staff, that meant patients would need transporting to a dialysis unit for treatment. • This increased risks to the critically ill patient as well as delaying necessary treatment. IHD was also shown to affect the condition of the critically ill patient adversely in a couple of main areas
- 9. • In 1977Peter Kramer developed the first of many Continuous Renal Replacement Therapies • By inserting a catheter into the patient’s femoral artery, blood was directed using an extracorporeal circuit through a semi-permeable membrane and then returned to the catheterised femoral vein. This technique was able to remove plasma water and dissolved solutes at a rate of 200-600 ml an hour via passive drainage using the principles that are now known as ultra-filtration and convection.
- 10. • It wasclear at this early stage that CRRT might have some important advantages over IHD including the haemodynamic stability, control of circulating volume, nutritional support and the ability to manage it fully within the intensive care unit, However there were also some shortcomings including the need to catheterise an artery and the limited solute clearance.
- 11. REQUIREMENTS FOR CRRT •A central double-lumen veno-venous hemodialysis catheter • An extracorporeal circuit and a hemofilter • A blood pump and a effluent pump. • With specific CRRT therapies dialysate and/or replacement pumps are required.
- 12. PRINCIPALS OF CRRT •Vascular access. • Semi-permeable membrane. • Transport mechanism. • Dialysate and replacement fluid.
- 13. I- VASCULAR ACCESS •Internal jugular. • Subclavian. • Femoral.
- 14. II- SEMI-PERMEABLE MEMBRANE •The basis of all blood purification therapies. • Water and some solutes pass through the membrane, while cellular components and other solutes remain behind. • 2 types: cellulose and synthetic. • Synthetic membranes allow clearance of larger molecules and are the primary type used in CRRT. • Filters are changed when they become contaminated, clogged or clotted.
- 15. III- TRANSPORT MECHANISMS A)ULTRAFILTRATION • The passage of water through a membrane under a pressure gradient. • Driving pressure can be +ve (push fluid through the filter), or –ve (pull fluid to other side of filter). • Pressure gradient is created by effluent pump.
- 16. B) CONVECTION • Movementof solutes through a membrane by the force of water “solvent drag”. • The water pulls the molecules along with it as it flows through the membrane. • can remove middle and large molecules, as well as large fluid volumes. • maximized by using replacement fluids.
- 17. D) DIFFUSION • Diffusionis the movement of a solute across a membrane via a concentration gradient. • For diffusion to occur, another fluid must flow on the opposite side of the membrane. • In blood purification this fluid is called dialysate. • When solutes diffuse across a membrane they always shift from an area of higher concentration to an area of lower concentration until the solute concentration on both sides of the membrane is equal.
- 18. IV- DIALYSATE ANDREPLACEMENT FLUID • Dialysate is any fluid used on the opposite side of the filter from the blood during blood purification. • As with traditional hemodialysis therapy, the dialysate is run on the opposite side of the filter,countercurrent to the flow of the patient’s blood. The countercurrent flow allows a greater diffusion gradient across the entire membrane,increasing the effectiveness of solute removal. • Typical dialysate flow rates are between 600– 1800 mL/hour.
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- 21. DIFFERENT MODES OFCRRT SCUF – SLOW CONTINUOUS ULTRA FILTRATION CVVH – CONTINUOUS VENO VENOUS HAEMOFILTRATION. CVVHD – CONTINUOUS VENO VENOUS HAEMODIALYSIS CVVHDF – CONTINUOUS VENO VENOUS HAEMODIAFILTRATION TPE – THERAPEUTIC PLASMA EXCHANGE HAEMOPERFUSION
- 22. • This modeof CRRF uses the principle of ultra filtration purely to remove excess fluid from the body and therefore is used to safely treat fluid overload. • For this reason fluids removed are generally not replaced. It works by pumping the patient’s blood through a filter which separates the fluid and molecules according to the size of the filter pores. • No dialysate or replacement fluid is used. SCUF – SLOW CONTINUOUS ULTRA FILTRATION
- 23. SCUF • Blood flow:80 – 200 ml/min • Duration • Ultrafiltration: 20-100 ml/hr (or total volume) • Anticoagulation • NO dialysate, NO replacement fluid
- 24. CVVH – CONTINUOUSVENO VENOUS HAEMOFILTRATION • An extremely effective method of solute removal and is indicated for uremia or severe pH or electrolyte imbalance with or without fluid overload. • Particularly good at removal of large molecules, because CVVH removes solutes via convection • Solutes can be removed in large quantities while easily maintaining a net zero or even a positive fluid balance in the patient. • The amount of fluid in the effluent bag is equal to the amount of fluid removed from the patient plus the volume of replacement fluids administered. • No dialysate is used.
- 25. CVVH • Blood flow:80– 200 ml/min • Duration • Ultrafiltration: 20-100 ml/hr • RF: 1000 – 2000 ml/hr , pre or post filter (up to 3 lit/hr). • Anticoagulation • NO dialysate
- 26. CVVHD – CONTINUOUSVENO VENOUS HAEMODIALYSIS • This mode is driven by diffusion of molecules across a semi-permeable membrane along a concentration gradient. • A dialysate with similar chemistry to normal blood is pumped counter-current to the blood through the filter. • Any molecules that are in greater concentration in the blood are drawn across into the dialysate and removed from the body. • Molecules which are low in the blood are also replaced by the normal levels in the dialysate
- 27. CVVHD • Blood flow:80– 200 ml/min • Duration • Ultrafiltration: 20 -100 ml/hr • Anticoagulation • Dialysate: 600 – 1800 ml/hr (up to 3 lit/hr). • NO replacement fluid
- 28. CVVHDF – CONTINUOUSVENO VENOUS HAEMODIAFILTRATION • This mode of CRRT is able to combine ultra filtration, convection and diffusion to enable the ultimate removal and replacement of solutes and fluids within the blood. • Combined to the fluids and molecules removed via convection and ultrafiltration the filter has a dialysate running counter current to blood flow to increase diffusive clearance. • Ultra-filtration and convection also help with fluid and solute removal with fluids being either partially or fully replaced.
- 29. CVVHDF • Blood flow:80 – 200 ml/min • Duration • Ultrafiltration: 20-100 ml/hr • Anticoagulation • Dialysate: 600 – 1800 ml/hr (up to 3 lit/hr). • Replacement fluid: 1000-2000 ml/hr, pre or post filter (up to 3 lit/hr).
- 30. TPE – THERAPEUTICPLASMA EXCHANGE • This mode is designed to separate the plasma from the other formed parts of the blood through a special filter membrane. The plasma is then replaced by a mixture of fresh frozen plasma and albumin. • Plasma exchange has shown good results in removing harmful cytokines in conditions like myastenia gravis, Guillian-Barre Syndrome, Good pasture syndrome and thrombotic thrombocytopenic purpura (TTP).
- 31. HAEMOPERFUSION • Is anextracorporeal treatment that passes the patient’s blood through a filter impregnated with an absorptive substance, for example, charcoal. • This is able to bind to certain toxins in the blood stream which removes them, returning the cleaned blood to the patient. • It has been shown to be effective against drugs like digoxin, glutethimide, phenobarbital theophiline and allow patients to maintain normal levels
- 32. DIALYSATE FLUIDS Component Bicarbonate-basedsolution (mmol/L) Lactate-based solution (mmol/L) Buffer 25.00 45.00 Potassium 0.00 01.00 Sodium 140.00 140.00 Glucose 0.00 10.00 Calcium 1.63 1.63 Magnesium 0.75 0.75 Chloride 100.75 100.75
- 33. Contd….• Dialysate fluidsare designed to mimic normal blood chemistry as closely as possible so as to encourage the correct amount of diffusion in the system if that technique is being used, but also to ensure that as a replacement fluid it does not cause imbalance in the blood chemistry. • Therefore to create the correct therapeutic action the chemistry of dialysate fluid does not differ all that much apart from the buffer agent used
- 34. • There hasbeen research completed into which replacement fluid produced better outcomes as there was concern that lactate-buffered fluids would reduce heart performance. • It has been found that lactate based solutions are not recommended for patients with cardiac or liver failure, as in a healthy liver the lactate would be converted into bicarbonate.
- 35. • However peoplewith liver dysfunction find that too much lactate remains causing increased acidaemia. • Even though bicarbonate solutions have shown this advantage over lactate based solutions in critical care, the lactate based solutions are cheaper and more stable in solution than bicarbonate ones and are generally used unless the patient has cardiac or liver issues.
- 36. INDICATIONS OF CRRT •Oliguria • Anuria • Hyperkalaemia • Severe Acidosis • Azotaemia • Significant organ edema • Uraemic encephalopathy/neuropathy • Uraemic pericarditis • Severe natraemia • Hemodynamically unstable patient
- 37. CONTRAINDICATIONS OF CRRT •Uncooperative
- 38. THE SET UPFOR CONNECTION The CRRT order form • In intensive care units medical staff will order continuous renal replacement therapies on a specialised form which will outline the necessary parameters and treatment goals. • The order form must include the following: • Patient’s name, medical record number, address, date of birth and sex for identification purposes. • The patient’s pre treatment weight (you may need to take one if not done)
- 39. • The prescribedfluid balance for the patient which will either be negative a certain volume or neutral. • The type of replacement fluid (Dialysate): Lactate or Bicarbonate based fluid • Type of anticoagulation for the circuit: Heparin, Regional heparinisation, citrate or no anticoagulant. (This will be related to the patients current coagulation blood results and so should be checked prior to commencing treatment)
- 40. COMPLICATIONS OF CRRT •Bleeding • Hypothermia • Electrolyte imbalance • Acid-base imbalance • Infection • Dosing of medications
- 41. NURSING MANAGEMENT • checkingthe patients' vital signs and talking with them to assess their condition • Teach patients about their disease and its treatment and answer if any questions • Overseeing the dialysis treatment from start to finish • Making sure patients are given the correct medications ordered by their doctors
- 42. • evaluate patients'reaction to the dialysis treatment and medications • Reviewing the patients' lab work, home medications and activities and letting the doctors know about changes in their patients' conditions • Helping patients follow-up with their transplant center • Supporting the entire care team in delivering quality care in a considerate, respectful manner
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