Factors associated with short-term survival in neonates with hyperammonemia

Hyperammonemia due to inherited metabolic disease can lead to neurological sequelae and death in neonates. Metabolite scavenger (MS) administration and dialysis can be helpful. We aim at analyzing the factors affecting short-term survival in neonates with hyperammonemia.

We conducted a retrospective study including all neonates with hyperammonemia admitted to the neonatal intensive care unit (NICU) of the Children's Hospital of Fudan University between April 2013 and June 2020.

Sixty-two neonates were enrolled in the study. Of these, 32 neonates were included in the non-survival group, and 30 neonates in the survival group. Compared to the survival group, the non-survival group had a higher peak ammonia level (882.2 vs. 433.4 µmol/L) (P=0.002), a shorter length of stay (5.7 vs. 22.3 d) (P<0.000), and higher rates of acidosis (19 vs. 10) (P=0.047), electrolyte disturbance (15 vs. 6) (P=0.033), coma (12 vs. 2) (P=0.005), and invasive mechanical ventilation (28 vs. 8) (P=0.000). A longer length of stay was the most significant protective factors in the multivariate logistic regression analysis, followed by MS administration. Factors of invasive mechanical ventilation, Δ<0 (Δ= last ammonia level - first ammonia level), coma and electrolyte disturbance established a risk score model that performed well in survival analysis. Area under ROC curve for survival length of hyperammonemia combined with peak ammonia levels was 0.737 (95% CI: 0.603-0.870).

MS administration is an effective treatment method for hyperammonemia in neonates, and increasing the length of stay in the NICU could help improve short-term survival. Further intervention should be administered when peak ammonia levels >406.5 µmol/L.