RENAL FAILURE IN ICU. Jo-Ann Vosloo Department Critical Care SBAH

Transcription

1 RENAL FAILURE IN ICU Jo-Ann Vosloo Department Critical Care SBAH

2 DEFINITION: RIFLE criteria

3 Criteria for initiation of RRT

4 Modes of RRT (options) CRRT = continuous renal replacement therapy SCUF : Ultra-filtration CVVH : Convection HV-CVVH(HF) : High volume convection CVVHD : Diffusion & Ultrafiltration CVVHDF SLEDD IHD PD : Convection, Diffusion, Ultra-filtration MPS = membrane plasma separation (plasmaphoresis, plasma exchange) : Convection, exchange HP = hemoperfusion (charcoal filter paracetamol poisoning, snake bite): Adsorption

5 Which mode of RRT is the best? Aspects that should be taken into consideration before the choice is made: - Haemodynamic side-effects - Ability to control fluid status - Biocompatibility - Risk of infection - Uremic control - Avoidance of cerebral oedema - Ability to allow full nutritional support - Ability to control acidosis - Absence of specific side-effects - Cost

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8 CRRT

9 CRRT

10 Indication: Modes CRRT SCUF: Mode (Slow continuous ultra-filtrate) Indications Diuretic unresponsive fluid retention (pulmonary oedema) CVVH/HV-CVVH: Continuous venovenous haemofiltration ± high volume (Use convection flow) AV1000 filter CVVH remove fluid and small, medium + large molecules. CVVH-HV Rather for metabolic acidosis. For cold, trauma patient with acidosis. ARF with shock, MOF, unconciuosness, hemodynamic instability, severe cardiac insufficiency Diuretic resistant fluid retension Removal of toxic metabolic products Life-threatening electrolyte imbalance e.g. hyperkalaemia Correction of acid-base balance e.g. metabolic acidosis Elimination of mediators in MOF, sepsis, ARDS, pancreatitis, trauma

11 Indication: Modes CRRT CVVHDF Mode Continuous venovenous haemodiafiltration (Convection, diffusion, Ultrafiltration) Filter: AV1000 Indications ARF with shock, MOF, unconsciousness, hemodynamic instability, severe cardiac insufficiency Diuretic resistant fluid retention Removal of toxic metabolic products Life-threatening electrolyte imbalance e.g. hyperkalaemia Correction of acid-base balance e.g. metabolic acidosis Elimination of mediators in MOF, sepsis, ARDS, pancreatitis, trauma (less effective than CVVH with identical volume) CVVHD Continuous venovenous haemodialysis (Diffusion and Ultra-filtration) Filter: HF80S/F40-60S/AV dialyser Renal insufficiency in ICU patients Removal of life-threatening electrolytes e.g. hypernatremia Correction of acid-base imbalance

12 Indication: Modes CRRT Mode Membrane Plasma Separation (MPS) Use a plasma filter (PSu2 or 1) Exchange 60% of estimated plasma volume Indication Removal of pathogenic proteins - Malaria - TTP - Hemolytic uremia - Gillian Barre - Removal of antibodies post-transplant Use FFP, Ringers and 20% Albumin combination to do exchange Hemoperfusion (HP) Removal of toxic substances, also proteinbound substances by adsorption Charcoal filter For snake bites, paracetamol and other poisoning

13 CRRT Current dose rate (dialysate or substrate): 30ml/h/kg) = 2,5l/h for 70kg person Blood flow rate: ±150ml/h or acc. to UFR/BPR ratio Advantages: No matter what technique is used, the following outcomes are predictable: 1. Continuous control of fluid status 2. Hemodynamic stability 3. Control of acid-base status 4. Ability to provide adequate protein rich nutrition, while achieving uraemic control 5. Control of electrolyte balance, including PO 4 = and Ca Prevention of swings of intracerebral water 7. Minimal risk of infection 8. Biocompatibility Disadvantages: 1. Needs the presence of specifically trained nurses 2. Higher cost 3. Issues with continuous circuit anti-coagulation and the potential risk of bleeding 4. Cannot disconnect Pt >1 hour to go for e.g. CT scan must change extra-corporeal circuit and reprime the lines

14 CRRT and circuit anti-coagulation

15 CCRT and circuit anticoagulation Full heparinisation: Pulmonary embolism, Myocardial infarction Heparin induced thrombocytopenia: Heparinoids or Prostacycline LMWH: Dose must be adjusted for renal failure patients

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18 Intermittend Hemodialysis (IHD) High dialysate flows: ml/h Treatment period: 3-4 hours every second day Implications: - Fluid has to be removed over very short period hypotension (repeated hypotensive episodes may lead to delayed renal recovery) - Solute removal is episodic (inferior acid-base control) (limited fluid and uremic control limitations on nutritional support) - Rapid solute shifts increases brain water content intracranial pressure - Membrane biocompatibility: Standard low-flux dialysis membranes is made of Cuprophane activates several inflammatory pathways further renal damage delayed recovery and? mortality.

19 SLEDD Limitations of IHD has led to the development of Sustained low efficiency daily dialysis Use IHD machine Over 8-12 hours Qd = 300ml/h Qb = 150ml/h

20 Peritoneal dialysis Now uncommonly used in developed countries for adult ARF in ICU Still used in children greater relative surface area alternatives too expensive or not available. Glucose rich dialysate is used Machines available that can deliver and remove dialysate at a higher flow rate. Shortcomings: - Sometimes inadequate solute clearance - High risk of peritonitis - Unpredictable hyperglycaemia - Fluid leaks - Protein loss - Interference with diaphragm function

21 Drug prescription during dialysis

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23 Textbook of Critical Care (Vincent) Conclusion