In this study, we compared the therapeutic efficacy of lung recruitment plus INSURE and INSURE alone for the preterm neonates with respiratory distress syndrome. The results showed that compared to the control group, the lung recruitment group had a significantly lower proportion of preterm neonates' need for MV within the72 h after extubation(23% vs. 38%, P = 0.025) and pulmonary surfactant administration, as well as shorter the MV duration. Nevertheless, there were no significant differences in other secondary outcomes, 4 parameters of blood gas, and the incidence of complications between the two groups. Multivariate logistic regression analysis demonstrated that the control group had a 2.17-time higher risk for need for MV than the lung recruitment group (OR: 2.17, 95% CI: 1.13–4.18; P = 0.021).In the mothers with hypertension, the infants presented a 2.41-time higher risk for requiring MV as compared with those of mothers with normotension (OR: 2.41, 95% CI: 1.15–5.05; P = 0.020). Taken together, these data suggested that lung recruitment plus INSURE can reduce the need for MV within 72 hours after extubation without increasing the incidence of complications and mortality.
Listaet al. conducted a clinical trial of preterm infants with respiratory distress treated with sustained lung inflation (25 cm H2O, sustained for 15 s )at birth and concluded that the application of sustained lung inflation at birth in preterm infants with respiratory distress may decrease the need for MV without inducing evident adverse effects as compared with a historical control group. Consistent with this observation, our results suggested that lung recruitment can effectively reduce the need for MV without increase the adverse effects. In addition, the MV duration and pulmonary surfactant frequency were both reduced in the lung recruitment group as compared with the control group, which were in line with previous findings [11, 12, 18–20]. The lung recruitment technique might positively affect the clearance of lung fluid and allows a more even distribution of air throughout the lungs, thus facilitating the formation of FRC. Therefore, the beneficial effects may be attributed to lung recruitment and FRC achievement provided by lung recruitment and the alveolar expansion by inflation.
BPD is a major complication of preterm birth  and has a complicated pathogenic mechanism. Immature lung development, acute lung injury, and abnormal repairment after injury are key points leading to BPD. One of the most important factors in the pathogenesis of BPD is Ventilator-induced lung injury.In this study, the incidence of BPD was lower in the lung recruitment group than the control group(33% VS 40%), but the difference did not reach statistical significance. The incidences of different severe BPDs also showed no statistical difference between the two groups. This result suggested that lung recruitment did not increase the accidence of BPD. In this study, lung recruitment did not increase the incidences of adverse effects, including IVH, NEC, PDA, ROP, which is in agreement with previous studies[13, 14, 18, 25].
In this study, two cases had pneumothorax in the lung recruitment group and three cases had pneumothorax in the control group, suggesting that lung recruitment did not increase the risk of pneumothorax. This result is consistent with previous reports[10, 14, 15, 25]. By contrast, Lista et al. have reported that patients with lung inflation treatment have a 4.57 times-high risk of pneumothorax than the control patients . The discrepancy might be attributed to different study subjects, and the effect of lung recruitment on pneumothorax should be further investigated.
In this study, no difference in mortality was found between the two groups. Two cases of death in the lung recruitment group were due to the abandonment of parents but not pneumothorax or other severe complications. This result suggested lung recruitment did not increase mortality. The comparison in the blood gas parameters between the two groups showed no significant difference, suggesting that lung recruitment did not impact the circulation and the rate of acidosis. This may be due to the comprehensive influence of ventilation improvement.
There are still some limitations to this study. First, the study was not double-blinded. The staffs performing the study also cared for the infants later on, which might affect the outcome. We tried to minimize this bias by strictly follow the trial protocol during the whole trial. In addition, this was a single-center trial and the sample size was still relatively small. In the future, a large multicenter trial should be conducted to validate the findings of this study.