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This presentation explores the controversies and clinical evidence surrounding the use of continuous renal replacement therapy (CRRT) in acute liver failure (ALF). Topics include hyperammonemia, intracranial hypertension, sepsis, and anticoagulation in liver patients.
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CRRT in Acute Liver FailureAkash DeepDirector - PICU King’s College HospitalLondonChairRenal/CRRT SectionEuropean Society of Pediatric and Neonatal Intensive Care (ESPNIC) 0
DISCLOSURE • Research grant from Mallinckrodt Pharmaceuticals– Terlipressin in paediatric HRS • Taskforce member for ESPNIC/SCCM joint septic shock guidelines – Adjunctive therapies in septic shock
Overview • Hyperammonaemia – raised ICP in ALF • Controversies in CRRT in ALF – why, when, how ? • Role of MARS, SPAD and TPE in Liver failure • Anticoagulation in liver Patients
Why patients with FHF die ? • Sepsis – MOSF • Cerebral edema /intracranial hypertension • SIRS at presentation associated with mortality - immune modulation
Clinical Evidence of Intracranial Hypertension. All ALF, n=1549. Incidence of Intracranial Hypertension in 3300 patients at King’s over 35 years Error bars are 95% CI. p<0.00001 Bernal et al. J Hepatol. 2011
Ammonia is central in the pathogenesis of Hepatic Encephalopathy 400 300 200 mol/L 100 0 AoCLF ALF Healthy Cirrhosis TIPSS ICP>25mmHg Olde Damink et al. Neurochem. Int. 2001
Arterio-Venous Ammonia in various beds P Arterial ammonia 92 (71-144) Venous ammonia 45 (29-95) a % extraction 46 % (32-59) Bernal Liver International 2008 Arterial ammonia 92 (71-144) Venous ammonia 77 (59-119) a Arterial and venous levels should not be used interchangeably in the assessment of risk of Cerebral Oedema
NH3 Inflammatory Mediators (e.g. NO) Hepatocellular necrosis and apoptosis Cerebral Blood Flow ICP Astrocyte swelling
GLUTAMINE GLUTAMATE H20 NH3 H20 H20 GLUTAMINE H20 H20 Astrocyte swelling & increased brain water Ammonia-glutamine-brain swelling hypothesis ASTROCYTE Ammonia
Ammonia levels and its brain delivery predicts brain swelling and advanced HE Clemmesen et al. Bernal et al. Hepatology, 2007 Jalan et al. J Hepatology; 2004 Oct;41(4):613-20 Bhatia et al. Gut. 2006 Jan;55(1):98-104.
Hyponatraemia potentiate ammonia effect on HE Gines et al Hepathology 2008
Controversies in RRT in Liver Failure • Why do patients with Liver failure develop AKI and why do they need to go on CRRT? • What is the best time to initiate RRT in patients with ALF? - Elective versus standard CRRT • What dose of RRT is the best dose? • Anticoagulation in CRRT for ALF • Ideal Extracorporeal Liver Assist Device (ELAD) – excretory and synthetic function
Survival in patients treated by RRT according to diagnoses: ppCRRT Registry Symons, Clin J Am Soc Nephrol, 2: 732, 2007 pCCRT Rome 2010
ELAD ? ? Bridging means identifying which patient is sufficiently lucky to survive
Acute Liver Failure Liver in some IMD (normal architecture) Cirrhotic Liver
Role of Liver Assist Devices • Survival Benefit ? • Improved Cardiovascular Stability • Improved HE, decreased ammonia • Control fluid balance (before/after ELT) • Increase delay to ELT, bridge to ELT • Standard use in ICU setting • Conducive Environment for Either Liver Regeneration /Liver Transplant Hepatology 1998:27:1050-5
Guidelines for CRRT in ALF at KCH No one indication is an absolute one for initiation of CRRT
WITH 35 MLS/KG/HR - At 1 hour AC – 39 AND AT 24 HOURS – 44MLS/MIN WITH 90 MLS/KG/HR – AT 1 HOUR – 85 AND AT 24 HOURS 105 MLS/MIN . Ammonia clearance is closely correlated with ultrafiltration rate. HF was associated with a fall in arterial ammonia concentration
HVHF - > 80mls/kg ultrafiltrate, Median flow of ultrafiltrate was 119 mL/kg/hr(80– 384). After 48 hours of treatment, mean arterial pressure (p = 0.0005), grade of hepatic encephalopathy (p = 0.04), and serum creatinine Overall mortality was 45.4% (n = 10). Emergency liver transplantation was performed in eight children. Five patients spontaneously recovered liver function
Primary outcome : Survival to hospital discharge with or without liver transplantation • Secondary outcome: arterial ammonia, lactate, percentage fluid overload, creatinine and mean arterial pressure
Need for more bridging modalities
Kaplan Meier Curve for CRRT patients who did not undergo transplant Since transplantation interferes with the natural progression of PALF; analysed patients didn’t undergo transplant
Conclusions Early implementation of high intensity CRRT which reduces ammonia within 48 hours may provide an increased window for either spontaneous regeneration of liver to take place or for the emergency liver transplant to become available probably by : improving haemodynamics, decreasing ammonia and brain swelling
CRRT modalities and Liver Assist Devices • CRRT – CVVH, CVVHD, CVVHDF – no evidence which is better • TPE – Therapeutic Plasma Exchange • TPE plus CVVH/HD • MARS • SPAD – Single Pass Albumin Dialysis
Performs the excretory as well as synthetic functions of the failing liver Courtesy – Fin Larsen
Primary endpoint - Liver transplantation-free survival during hospital stay. Secondary- endpoints- survival after liver transplantation with or without HVP with intention-to-treat analysis. Part B - A proof-of- principle study evaluating the effect of HVP on the immune cell function was also undertaken.
Nor-epinephrine need Effect on INR
Overall hospital survival - 58.7% HVP group vs. 47.8% for controls • The incidence of severe adverse events was similar in the two groups. • Systemic inflammatory response syndrome (SIRS) and sequential organ failure assessment (SOFA) scores fell in the treated group compared to control group
Conclusions on plasma exchange in ALF a) Increases blood pressure and reduces need for vasopressorsb) Reduces WC and SIRS1. Works by reducing the pro-inflammatory response - probably by immune modulation – the pro-inflammatory response2. Improves transplant-free survival and Liver functiona) by attentuating innate immune activation and amelioration of MOSFb) Reduces INR, Bilirubin, ALT and circulating ammonia3. Attenuates multiorgan failure - Reduce SIRS, SOFA and CLIF-SOFA scores
Continous vv hemofiltration and plasma exchange in infantile ALF - NCCH, Tokyo, Japan Simultaneous CVVHDF and PEX PEX circuit was attached as a side flow to the CVVHDF circuit and was removed after each PEX treatment course 17 infants, 88% survival Ide and coll. PCCM Accepted
Excellent safety profile Bridged 75% patients to LT
Role of Tandem therapies • CRRT plus TPE /Plasmapheresis • Combination of therapies – CRRT, TPE, MARS Safety and Efficacy of Tandem Hemodialysis and Plasma Exchange in Children Schaefer, Akos Ujszaszi, Susanne Schaefer, Karl Heinz Heckert, Franz Schaefer, and Claus Peter Schmitt Paglialonga F, Ardissino G, Biasuzzi A, Testa S, Edefonti A. Tandem plasma-exchange and haemodialysis in a paediatric dialysis unit. Pediatric Nephrology March 2012, Volume 27, Issue 3, pp 493–495
SUMMARY No Evidence for RRT in Liver patients Should we undertake CRRT in ALF Yes - and review : population data vs individual care Why ? –Neuro-protection, metabolic disarray, bridge for recovery or transplant When Earlier - need new markers Mode CRRT – unstable, TPE coming in fashion !! Access sites Internal Jugular Dose No evidence in Paediatrics High – gaining popularity Anticoagulation - YES PGI2 and /or low dose heparin