[Clinical investigation of formula feeding in extremely low birth weight infants]

To explore the relationship between gastric retention and full enteral feeding during the course of feeding in extremely low birth weight (ELBW, birth weight <1 000 g) infants.

A total of 43 ELBW infants were fed with formula according to the strategy for premature infants feeding of Canadian Society of Neonatology. The information such as gastric retention, the time they finish full enteral feeding and sucking spontaneously and complication were recorded. These infants had transition to full enteral feeding step by step since initiating formula feeding on the second day of life. The volume of gastric retention and the duration of gastric retention was analyzed with the time of attaining full enteral feeding and sucking spontaneously by linear regression.

Forty-one infants finished the course, the remaining 2 infants got necrotizing enterocolitis (NEC) and were rescued by surgery. The incidence was 4.6%. In 18 infants full enteral feeding could not be initiated successfully on the second day of life, the incidence was 43.9%. The peak duration of gastric retention was the first week of feeding. The average time of attaining enteral feeding was (26.71 ± 12.24) days. The proportion of different residual contents was simlar, the major content was milky content after 3 weeks of feeding. The gastric retention time had a significant effect of on the time of attaining full enteral feeding (β = 1.045, P = 0.001) and sucking well (β = 0.787, P = 0.034) .

The course of formula feeding ELBW infants to attaining full enteral feeding was a long period, in the early stage of formula feeding the occurrence of gastric retention was high; the amount of formula during the first week of feeding should be slowly increased as compared to the second week; the present strategy and aggressive strategy should be done 2 weeks later. The time of attaining full enteral feeding can be predicted by the duration of gastric retention.