Objective: This study aimed to compare nitrogen balance and biochemical tolerance of early aggressive versus late total parenteral nutrition in very-low-birth-weight (VLBW) infants over the first week of life.
Study design: In all, 32 ventilator-dependent preterm infants were prospectively randomized into two groups. The Early Total Parenteral Nutrition (ETPN) group received 3.5 g/kilo-day amino acids (AA), and 3 g/kilo-day of 20% Intralipid (IL), starting within 1 hour after birth. The Late Total Parenteral Nutrition group (LTPN), started on a solution containing glucose during the first 48 hours of life, followed by 2 g/kilo-day of AA and 0.5 g/kilo-day of IL. For the LTPN group AA and IL were each increased by 0.5 g/kilo-day to a maximum of 3.5 and 3 g/kilo-day, respectively.
Results: Nitrogen retention was significantly greater in all infants in the ETPN group throughout the 7-day study period. All infants in the LTPN group were in negative nitrogen balance during the first 48 hours of life, while those in the ETPN group were in positive nitrogen balance throughout. The mean (+/-SD) nitrogen retention in the ETPN was 384.5 mg/kilo-day (+/-20.2), compared to 203.4 mg/kilo-day (+/-20.9) in the LTPN group (p <0.001). In each of the first 5 days of life, energy intake was significantly greater in the ETPN group compared to the LTPN group (p <0.001). Mean fluid intake during the study period was similar between, the ETPN and the LTPN groups (162 and 165 cm3/kilo-day, respectively). The mean weight gain was similar in the ETPN and LTPN groups. Plasma levels of cholesterol, triglycerides, bicarbonate, blood urea nitrogen, creatinine, and pH were similar in both groups during the study period. Mean (+/-SD) serum glucose in the LTPN group was higher, but remained in normal range (101.1+/-5.2 and 80.8+/-5.4 mg/kilo-day, respectively). The mean peak serum bilirubin was significantly higher in the ETPN group, compared to The LTPN group (7.7 and 6.2 mg/dl).
Conclusion: This study shows that aggressive intake of AA and IL can be tolerated immediately after birth by VLBW infants. Also, ETPN significantly increased positive nitrogen balance and caloric intake, without increasing the risk of metabolic acidosis, hypercholesterolemia, or hypertriglyceridemia.