BCC Lam

Meconium aspiration syndrome (MAS) is a major cause of respiratory morbidity and mortalities in neonates. Local study showed that the incidence of MAS was 1.5% of all newborn babies. Severe MAS necessitating mechanical ventilation occurred in 1.8 per thousand deliveries. The present practise of combined obstetric and paediatric suctioning of the airway at birth was not completely effective to prevent MAS. The pathophysiology of this disorder was related to mechanical obstruction of airway and the inactivation of the surfactant system by the meconium leading to pulmonary atelectasis. This will be followed by development of chemical pneumonitis and secondary bacterial infection. The present treatment modalities available for severe MAS includes conventional mechanical ventilation, high frequency oscillatory ventilation, surfactant replacement therapy and extracorporeal membrane oxygenation for refractory cases complicated by persistent fetal circulation. The must logical way to treat MAS should be to remove the residual meconium from the airway and the preservation of the surfactant system. In vitro study has shown that natural surfactant can increase the mucociliary transportability and decrease the stickiness of meconium. We propose to use diluted surfactant solution at a concentration of 5mg phospholipid/ml as a tracheo-bronchial lavage fluid to wash out the meconium and to preserve the surfactant system. We have recruited 6 consecutive term neonates over 1 1/2 years period whom had severe MAS necessitating mechanical ventilation with oxygenation index (OI) >= 15 within 6 hours after birth. They were lavaged with 15ml/kg of natural surfactant solution (Survanta - TA). The survival, OI and arterial alveolar Oxygen tension ratio (a:A PaO₂) at 48 hours, the duration of ventilation and oxygen therapy compared favourably with historic controls with similar initial OI and a:A Pa ratio. The process of administering the surfactant lavage was well tolerated with no air leak complication. The preliminary result of a randomized control study of surfactant lavage using Bovine Lipid Extract Surfactant (BLES) in a rabbit model of meconium aspiration will also be presented.

In summary, our experience demonstrated that surfactant lavage if performed early, appears to be an effective and safe method for treatment of severe MAS.