To study the clinical characteristics, treatment strategies and outcomes of very low birth weight infants (VLBWI) and extremely low birth weight infants (ELBWI), and to provide references for the treatment of them.

From of 1 January 2009 to 31 December 2015, a total of 1 146 cases of VLBWI/ELBWI who were hospitalized in Department of Neonatology, West China Second University Hospital, Sichuan University were recruited as research subjects. According to the gestational ages, the VLBWI/ELBWI were divided into 4 groups: <28 weeks group (n=84), and ≥28-32 weeks group (n=679), ≥32-37 weeks group (n=378), ≥37 weeks group (n=5). The clinical characteristics of each group were analyzed, and hospitalization time, survival rate, rate of using ventilator, rate of the main complications, and the situation of giving up treatment were statistically compared among groups.

Among 1 146 cases of VLBWI/ELBWI, there were 1 141 premature infants and 5 full-term infants. Because the number of full-term infants was too small, they were not analyzed by statistical methods, <28 weeks, ≥28-32 weeks, ≥32-37 weeks group were compared by related statistical methods. The results showed as follows. ①There were significant differences among 3 groups in hospitalization time and survival rate (Z=34.667, P<0.001; χ²=71.012, P<0.001). And the smaller of gestational age, the longer of hospitalization time, the lower of survival rate among those 3 groups. ②Rates of using invasive ventilation in <28 weeks group were higher than those in ≥28-32 weeks group and ≥32-37 weeks group, and both the differences were statistically significant (χ²=53.001, 162.157; P<0.001). Rate of using noninvasive assisted ventilation in <28 weeks group and ≥28-32 weeks group were higher than those in ≥32-37 weeks group, and both the differences were statistically significant (χ²=21.872, 74.418; P<0.001), but there was no significant difference between <28 weeks group and ≥28-32 weeks group in the rates of using noninvasive assisted ventilation (P>0.05). There were significant differences in durations of noninvasive assisted ventilation treatment among 3 groups by pairwise comparison (Z=-4.077, P<0.001; Z=-4.655, P<0.001; Z=-2.879, P=0.002), and the smaller of gestational age, the longer duration of noninvasive assisted ventilation treatment. ③There were significant differences among common complications, such as neonatal respiratory distress syndrome (NRDS), severe intracranial hemorrhage (Ⅲ-Ⅳ), bronchopulmonary dysplasia (BPD), retinopathy of prematurity (ROP) in 3 groups (χ²=111.662, 74.639, 58.076, 70.049; P<0.001), and the smaller gestational age, the higher incidences of aboved complications among 3 groups. There were significant differences in the incidences of apnea and intrauterine infection in 3 groups (χ²=59.683, P<0.001; χ²=25.937, P<0.001), and the incidences of apnea and intrauterine infection in <28 weeks group and ≥28-32 weeks group were higher than those in ≥32-37 weeks group, and all the differences were statistically significant (χ²=19.586, 57.893, P<0.001; χ²=10.146, 25.019, P<0.001), but there were no significant differences between <28 weeks group and ≥28-32 weeks group in the incidences of apnea or intrauterine infection (P>0.05). ④There were significant difference in 3 groups of rates of abandoned treatment (χ²=18.636, P<0.01). The smaller gestational age, the higher rate of abandoned treatment among 3 groups. Among the dead of VLBWI/ELBWI, the percentage of death after abandoned treatment was 73.8% (141/191).

In the VLBWI/ELBWI, the smaller gestational age, the higher rate of complications, higher use rates and longer use time of ventilations, and the lower survival rate. Reducing the proportion of abandoned treatment can improve the survival rate of VLBWI/ELBWI.