Results
95 preterm infants with confirmed MAS were screened during the ten years period (Jan, 2010 to Jan, 2020), 2 case were excluded owing to missing data, 1 case were excluded owing to extremely severe abdominal distension that his parents chose to give up, 92 preterm neonates were finally included, consisting of 31 non-survivors and 61 survivors. The total mortality in this study was 33.7%, while female account for 40% of all involved preterm infants. Their median gestational age was 33.4 weeks, while their mean birth weight was 1925.2 g. Among all the infants, 17 (18.5%) premature infants were small for gestational age.
Table 1 outlines the baseline features compared between the non-survival group and survival group. Risk was substantially higher among those were female. Compared with the survivors, infants in the non-survival group were more likely to be in need of resuscitation. In comparison with infants of non-chorioamnionitis mothers, infants of mothers affected by chorioamnionitis were more likely to die. Infants of mothers undergoing premature rupture of membranes(>18h) were more frequently seen in the non-survival group. Surfactant or inhaled nitric oxide were more likely to administrated in non-survival group. Conversely, compared with the survival group, the non-survival group were in lower birth weight and smaller proportion of small for gestational age. Mothers of infants in the non-survival group were less likely to experience cesarean section and suffer from gestational diabetes mellitus or pregnancy-induced hypertension. Potential of hydrogen (pH) value and partial pressure of arterial oxygen (PaO2) were lower in the survival group compared with the non-survival group. The median durations of ventilation were 108 hours (survival group) and 48 hours (non-survival group), at the same time the median hospitalization stay of those who survived was 23 day, longer than that of those who dead (their median hospitalization stay was 2 days).
Complications were compared between the two groups showed in table 2. It is suggested that persistent pulmonary hypertension and pulmonary hemorrhage were statistically in correlation with mortality of MAS in preterm infants. Meanwhile, majority of complications listed such as sepsis, necrotizing enterocolitis, pneumothorax, intracranial hemorrhage, shock, patent ductus arteriosus, anemia, myocardial injury, and metabolic acidosis were more frequently seen in the non-survival group.
Table 3 shows the independent risk factors for mortality by multivariate regression analysis. The parameters included in the regression model were all variables significant in the univariate analysis, three risk factors were significantly associated with mortality of MAS in preterm infants: female (P=0.011), persistent pulmonary hypertension (P=0.033), and pulmonary hemorrhage ( P=0.006).