OBJECTIVESevere respiratory distress syndrome (RDS) caused by pulmonary surfactant (PS) deficiency is described not only in preterm infants but also in term babies delivered via caesarean section, especially before the onset of labour (elective caesarean section). Once RDS of term neonates happened, mechanical ventilation is needed, and the infants were at high risk of developing further complications such as persistent pulmonary hypertension of neonates (PPHN), pulmonary air leak and cardiovascular instability, even fatal outcome cannot be avoided. The present study aimed to analyze the association between the elective caesarean section and respiratory distress syndrome (RDS) in term neonates, and to determine the related factors and outcomes of RDS cases in neonatal intensive care unit (NICU) and neonatology ward.

METHODSA retrospective study was conducted at the NICU and the Neonatology Ward of A center (Children's Hospital of Zhejiang University) and the NICU of center B (Obstetrics and Gynecology Hospital of Zhejiang University) on 90 term infants who were diagnosed as RDS between June 2006 and June 2008. The general clinical data, mode of delivery, severity of the radiological sign, pulmonary surfactant (PS) application, the onset time and duration of mechanical ventilation, the ratio of PaO(2) to FIO(2) before mechanical ventilation, oxygenation index (OI), duration of oxygen supplementation, the length of hospital stay and complications including pulmonary air leaks (pneumothorax, pulmonary interstitial emphysema), PPHN, systemic hypotension and ventilator-associated pneumonia (VAP) were collected. The gestational age distribution was studied in RDS cases delivered by elective caesarean section, and the comparative analysis and non-conditional logistic regression analysis wer performed for clinical characteristics and risk factors between the RDS cases with or without complications. P < 0.05 was considered to be significant.

RESULTSThere were 88 episodes of elective caesarean section in 90 RDS patients. The proportion of elective caesarean section was 97.8% (88/90). The number of RDS cases was reduced gradually with the increase of gestational age and the constituent ratio of RDS at 39 w and at 40 w was significantly lower than that of 37 w and 38 w. By logistic regression analysis, the onset time of mechanical ventilation > 12 h independently predicted complications in RDS of term neonates (odds ratio 12.667, 95% confidence interval, i.e., CI 1.455 to 110.300, P = 0.021). Moreover, there was a significant difference in the admission age (t = 11.833, P = 0.001), severity of the radiological findings (t = 4.85, P = 0.028), PS application (t = 11.911, P = 0.002), the onset time of mechanical ventilation (t =10.051, P = 0.018), the ratio of PaO(2) to FIO(2) before mechanical ventilation (chi(2) = 4.184, P = 0.005), OI > 25 (t = 4.737, P = 0.03), duration of oxygen supplementation (chi(2) = 10.475, P = 0.001), systemic hypotension (t = 11.020, P = 0.01) and the length of hospital stay (t = 9.827, P = 0.002) between the two centers.

CONCLUSIONSevere RDS can occur in term babies after elective caesarean section, gestational age at the time of elective caesarean section may also be important for RDS in term neonates. The onset time of mechanical ventilation > 12 h independently predicted complications in RDS of term neonates. The main complications of RDS in term neonates were PPHN, pulmonary air leaks and systemic hypotension. Early diagnosis, early intervention can significantly reduce the complications, alleviate the severity and shorten their time for oxygen therapy and their length of stay in NICU in term RDS infants.