Acute hemodialysis for hyperammonemia in small neonates

Neonatal metabolic emergencies require a multidisciplinary team approach for supportive management that has increasingly come to feature renal replacement therapies in addition to nutritional support, the use of pharmaceutical agents, and testing to guide management and provide a definitive diagnosis. An increased appreciation for the mechanisms involved in ammonia neurotoxicity has placed greater emphasis on the need for its rapid yet safe resolution to optimize long-term prognosis. We examined our experience of intermittent hemodialysis (HD) and considered (1) the feasibility of HD in low-weight neonates, (2) the rate of decrease in ammonia, (3) complications during HD in small neonates weighing <4 kg presenting at University Children's Hospital between 1999 and 2002. Additionally, we review the current cellular and molecular mechanism of ammonia-induced brain injury. All patients tolerated intermittent HD and all required pressor agents. We primed all our patients with 20 U/kg of heparin and there was no subsequent need for further heparinization. We also noted that hemodynamic instability persisted during the first 1-2 h of the procedure and improved thereafter, as indicated by a decreased need for pressor agents. All neonates are alive to date. In conclusion, HD remains an effective and practical mode of renal replacement therapy having readily managed complications in preterm neonates weighing <4 kg with metabolic disorders.