To investigate clinical characteristics of severe meconium aspiration syndrome (MAS) complicated with acute lung injury (ALI) and measures for the prevention and treatment of MAS complicated with ALI in order to reduce mortality.

A total of 56 neonates with a diagnosis of severe MAS complicated with ALI were admitted to our Neonatal Department from September 2009 to March 2011 and divided into two groups based on PaO₂/FiO₂ level: PaO₂/FiO₂≤100 group (n=13) and PaO₂/FiO₂>100 group (n=43). The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Maternal and Child Health Hospital of Xiamen City. Informed consent was obtained from the parents of each participating neonate. No significant differences were found between two groups in the methods of delivery, gender distribution and birth weight of neonate (χ²=1.5, 2.7, 1.9; P>0.05).

Hypoxemia, hypercapnia and decreased lung compliance occurred more serious in neonates of severe MAS complicated with ALI(PaO₂/FiO₂≤100 group vs. PaO₂/FiO₂≥100 group)(P<0.001). Chest radiographs commonly indicated pulmonary parenchymal opacities and air bronchograms(χ²=5.28, r=1; P<0.05). These cases required long-term ventilator therapy [(62.15±27.61) h vs. (42.12±19.62) h, P<0.05] and often complicated with persistent pulmonary hypertension of the newborn(PPHN)(P=0.01). The 13 neonates of severe MAS complicated with ALI(PaO₂/FiO₂≤100 group) were treated with high frequency oscillatory ventilation (HFOV) after admission.Among them, 10 cases(76.9%, 10/13) were treated with PS by endotracheal intubation and 3 (23.1%, 3/13)were treated with inhalation nitrogen monoxide(iNO). After 8-12 hours' treatment with ventilation, arterial blood analysis showed significantly improved oxygenation and alveolar ventilation(P<0.001).

The newborns of severe MAS complicated with ALI showed severe hypoventilation and dysfunction of oxygenation. Combined application of HFOV, PS and iNO strategy can effectively improve oxygenation. But whether it could be the most promising treatment for severe MAS complicated with ALI, it still need multi-center, large-sample random control trials to confirm.