[The status of protein intake and energy supply in the early life of very/extremely low birth weight infants].

OBJECTIVE: To study the relationship of protein intake and energy supply with the physical growth in very/extremely low birth weight infant at their early life.

METHOD: Retrospective survey was performed in Neonatal Intensive Care Unit (NICU) in Peking University First Hospital. Inclusion criteria were preterm infant, birth weight < 1500 g, hospitalization for longer than 2 weeks, discharge with body weight greater than 1800 g. The infants were divided into two groups according to gestational age (GA). GA < 32 weeks and ≥ 32 weeks. Physical growth and its relation with the protein intake and energy supply were analyzed. The predictive value of serum blood urea nitrogen (BUN) on protein intake was studied.

RESULT: Ninety-three very/extremely low birth weight infants were involved, 69 in GA < 32 weeks group and 24 in GA ≥ 32 weeks group.Compared with GA ≥ 32 group, GA < 32 weeks preterm infants had more weight loss, (9.2 ± 4.4)% vs. (5.0 ± 3.1)%, P = 0.000; slower birth weight recovery (10.6 ± 3.8) d vs. (7.1 ± 2.6) d, P = 0.000; poorer weight gain at 1, 4, 5 weeks of life, (-4.5 ± 9.3) g/ (kg·d) vs. (3.4 ± 6.9) g/ (kg·d), P = 0.000 , (13.5 ± 7.3) g/ (kg·d) vs. (19.2 ± 4.9) g/ (kg·d), P = 0.001, (14.6 ± 5.6) g/ (kg·d) vs. (18.2 ± 4.5) g/ (kg·d), P = 0.031; less energy supply at 1 to 5 weeks (P value was 0.000,0.000,0.025,0.001,0.008 respectively) and less protein intake at 1, 4, 5 weeks of life (P value was 0.009,0.006,0.032). Extrauterine growth retardation (EUGR) was still predominant in our subjects, 47.8% in GA < 32 weeks group, and 95.8% in GA ≥ 32 weeks group, P = 0.000. The incidence increased greater in GA < 32 weeks infants, 43.5% vs. 20.8%, P = 0.000.The duration of weight loss and mechanical ventilation correlated negatively with weight gain rate, respectively β = -0.591, P = 0.000 and β = -0.281, P = 0.005; the average energy supply and time taken to reach full enteral feeding were factors improving weight gain, respectively β = 0.202, P = 0.021 and β = 0.354, P = 0.000. After birth, serum BUN declined gradually. Positive relation showed between average protein intake at 3(rd) week and BUN level at the end of 3 weeks, r = 0.420, P = 0.000. Serum BUN 1.44, 1.49 mmol/L at the end of 3(rd) and 4(th) week were cut-off predictors for protein intake less than 3 g/(kg·d) at related period, sensitivity and specificity were 65.3%, 83.3% and 60%, 80% respectively.

CONCLUSION: No enough protein intake and energy supply, poor weight gain are critical problems in the management of very/extremely low birth weight infants. Prevention from NEC, appropriate parenteral/enteral nutrition transforming will benefit their physical growth. Low serum BUN after 3 weeks of life is a valuable predictor of low protein intake.