(P16-025-23) Exploratory Observation of Arginine Metabolism in Parenteral Nutrition Fed Neonates

Objectives: 1) To correlate arginine intake and plasma arginine with arterial ammonia and plasma glucose

2) To evaluate the relationship between arterial and capillary ammonia

3) To evaluate the relationship between various amino acids involved in arginine metabolism with arterial ammonia in parenteral nutrition fed neonates at SickKids NICU

Methods: 17 PN fed appropriate for gestational age neonates: gestational age 34 ± 4 (mean ± SD) had one to two blood samples taken 24-48 hours apart for measurement of plasma AA, glucose, arterialized, and capillary ammonia. Demographic information and nutrient intake were collected. Statistics: Regression analysis was conducted to assess relationships between arginine intake, arterial ammonia, plasma arginine, and plasma glucose. Paired t-test assessed the difference between capillary and arterial ammonia.

Results: Neonates received 73 ± 27 kcal/kg (mean ± SD) and protein intake of 3.0 ± 0.9 g/kg (mean ± SD). No relationship was found between arginine intake, plasma ammonia, plasma arginine, and plasma glucose (p >0.05). Capillary ammonia was 51 ± 23 umol/L (mean ± SD), ranging from 19 to 91 umol/L. Arterial ammonia was 21 ± 11.8 umol/L (mean ± SD), ranging from 9 to 62 umol/L. Capillary ammonia was significantly higher than arterialized ammonia (p < 0.05). One neonate developed hyperammonemia based on arterialized ammonia samples. 78% had hyperammonemia based on capillary ammonia (reference range < 50 umol/L).

Conclusions: The current findings demonstrate that the arginine content of current neonatal PN AA solutions is adequate to prevent hyperammonemia and that capillary samples may not be valuable in assessing ammonia status.

Funding Sources: The study is funded by the Canadian Institutes of Health Research.