12 Acute Hemodialysis therapy in Neonates with Inborn Errors of Metabolism Eisenstein I1, Tarabeih M1, Magen D1, Pollack S1, Halberthal M3, Hershman E3, Attias O3, Hadash A3 , Mandel H2, BarJoseph G3, Zelikovic I1. 1 Division of Pediatric Nephrology, 2Pediatric Metabolic Unit and 3Pediatric Intensive Care Unit, Meyer Children's Hospital, Rambam Health Care Campus; Faculty of Medicine, Technion-Israel Institute of Technology; Haifa, Israel. Introduction: Inborn errors of metabolism (IEOM) such as urea cycle defects (UCD) and organic acidemias (OA) can cause rapid, devastating and irreversible damage to the neonatal brain if not promptly treated. The most efficient therapy for IEOM-induced life-threatening metabolic crisis is hemodialysis (HD). It rapidly removes toxic compounds that accumulate in these disorders from the circulation. Data on the use of HD in IEOM, in particular in the neonatal period, is scarce. Objectives: To summarize our experience with acute HD in neonates with IEOM- induced metabolic/clinical crisis and to describe the outcome of these neonates. Patients and Methods: We analyzed the demographic, clinical, and biochemical data of all neonates with IEOM who were admitted to our Pediatric Intensive Care Unit between January 2004 and December 2011 with a metabolic crisis necessitating HD therapy. Results: Thirteen neonates (M:F 6/7; Arab/Jews 12/1) with IEOM [6- UCD, 2-mitochondrial cytopathies (MC), 3- maple syrup urine disease (MSUD) and 2 - other OA] had uneventful delivery and were admitted because of metabolic/neurological deterioration starting at 48h -14 days of age. Median age and weight of the infants at initiation of HD was 6.3 days and 3004 g, respectively. HD was performed through double-lumen, 6.5- French, Gambro brand acute catheter inserted blindly or under sonographic guidance into the internal jugular vein; Gambro AK200 dialysis machine and tubing, and Fresenius FXpaed dialyzers were used. A total of 28 dialysis sessions (3 hours each; at least 2 sessions per every patient) were performed. The first HD session markedly decreased (91.5%) mean ammonia level in UCD and MC patients from 1071 to 86 μmol/L (nl: 53-90), and markedly decreased (90.7%) mean leucine level in MSUD patients from 2737 to 253 μmol/L (nl: 70-240). The second dialysis session decreased the rebounded mean ammonia and leucine levels from 433 μmol/L and 823 μmol/L to 69 μmol/L and 80 μmol/L, respectively. The HD procedure was free of complications, resulted in marked clinical improvement in 10 patients, and enabled the initiation of the appropriate dietary/pharmacological therapy in all patients. Ten (77%) of the infants survived, and three (23%) succumbed to their metabolic disease in the neonatal period. Conclusions: HD in neonates with IEOM is safe, very efficient, and life-saving when performed by skilled personal and in the appropriate setting.