To explore the timing options of high frequency oscillatory ventilation (HFOV) for treating preterm infants with respiratory distress syndrome (RDS), and the successful treatment rates of HFOV and conventional mechanical ventilation (CMV).

From February 2015 to February 2017, a total of 104 preterm infants who were diagnosed as RDS in Suining Central Hospital and required mechanical ventilation were selected as research subjects. They were randomly divided into preferred CMV group (n=51, the preferred mechanical ventilation mode was CMV) and preferred HFOV group (n=53, the preferred mechanical ventilation mode was HFOV). In preferred CMV group, CMV treatment succeeded to 33 preterm infants, while failed to 18 preterm infants, and they changed to HFOV treatment after CMV treatment failed. The general clinical data before ventilation, the differences of oxygen index (OI), fraction of inspired oxygen (FiO₂), arterial and alveolar oxygen ratio (a/APO₂) before and 2, 12, 24, 48 hours after ventilation, the treatment situation, incidences of complication and clinical outcomes between two groups were analyzed by statistical methods. The complications, clinical outcomes and clinical data before CMV treatment between preterm infants by CMV treatment succeeded and preterm infants by CMV treatment failed in preferred CMV group were compared statistically. Meanwhile, the related influencing factors of CMV failure were analyzed. This research was approved by the Ethics Committee of Suining Central Hospital, and the treatment protocols were informed to all patients′ parents and all the parents signed the informed clinical research consents.

①There were no statistically significant differences between two groups in gestational age at birth, birth weight, Apgar score of 1 min after birth, admission age, gender ratio, ratios of very low birth infant and grade Ⅲ-Ⅳlesion of RDS in chest X-ray, rates of using pulmonary surfactant (PS), using the first agent PS within 6 hours after birth, using two agents of PS and antenatal glucocorticoids therapy for fetal maturation (P>0.05). ②There were no statistical differences between two groups in OI, a/APO₂ and FiO₂ before mechanical ventilation (P>0.05). While 2, 12, 24, 48 hours after mechanical ventilation, OI and FiO₂ in preferred CMV were higher and a/APO₂ were lower than those in preferred HFOV group, and all the differences were statistically significant (P<0.05). ③The mechanical ventilation duration, hospital stay and oxygen treatment duration in preferred CMV group all were longer than those in preferred HFOV group, and all the differences were statistically significant (P<0.05). There were no statistical differences between two groups in the incidences of pneumothorax, bronchopulmonary dysplasia, intracranial hemorrhage, pulmonary hemorrhage (P>0.05). The mortality of preferred HFOV group was 9.4% (5/53) which was significantly lower than that of 25.5% (13/51) in preferred CMV group, and the difference was statistically significant (P=0.030). ④In preferred CMV group, the mortality of preterm infants by CMV treatment succeeded was 12.1% (4/33) due to other complications after successful CMV treatment, which was significantly lower than the mortality of preterm infants by CMV treatment failed (50.0%, 9/18), and the difference was statistically significant (P=0.006). Ratios of grade Ⅲ-Ⅳ lesion of RDS in chest X-ray and very low birth infant of preterm infants by CMV treatment failed were significantly higher than those of preterm infants by CMV treatment succeeded, rate of using PS was significantly lower than that of preterm infants by CMV treatment succeeded, and all the differences were statistically significant (P<0.05).

Choosing HFOV as primary ventilation for treating preterm infants with RDS may improve the treatment success rate and prognosis of preterm infants with RDS than CMV. The assessment of RDS grade in chest X-ray, whether it is very low birth infant and the condition of using PS before ventilation may help the best timing choice of HFOV.