Surfactant therapy in infants with MAS

Surfactant can represent a new solution for the therapy of the Meconium Aspiration Syndrome (MAS). This possibility is suggested by a Chinese randomised clinical trial, performed in 19 neonatal intensive care units. No specific therapies are, at present, available for MAS: the treatment is usually based on oxygen supplementation and positive pressure mechanical ventilation. Most severe cases require ExtraCorporeal Mechanical Oxygenation (ECMO) which is a very expensive and not often available procedure. Some groups suggested an alternative therapy based on pulmonary surfactant, but the results could not provide evidence for a superior efficacy of surfactant administration compared to conventional treatments. Therefore, the aim of this study was to evaluate the efficacy and the safety of the administration of surfactant for the treatment of severe MAS.

All infants enrolled in the study (n = 61) received standard care; in addition, surfactant (Curosurf â , 200 mg/kg) was administrated to the treatment group (n = 31). In the case of a deteriorated Oxygenation Index (OI >2 from baseline), repeated doses of 200, 100 and 100 mg/kg were given at 6/12 hours intervals, up to a maximum of four doses. The improvements in oxygenation and ventilation were evaluated 24 hours after surfactant treatment. The reduction of OI less than 10 and a 100% increase of pre-treatment arterial/alveolar ratio (a/A) PO 2 ratio over baseline were defined as target parameters to assess an improvement in oxygenation and ventilation.

Infants in the surfactant group showed an improvement in oxygenation, if compared with the control group. In fact, in the treatment group OI index was lower than in the control group and a significant higher number of infants reached a 100% increase of a/A PO 2 , compared to controls. Moreover, the need of repeated doses was limited. Only 1 infants out of 30 died in the study group (3 out of 30 in the control). The occurrence of complications between the two groups was not significantly different.

Taken together, these findings suggest that the early intervention with surfactant could improve oxygenation and therefore prevent the need for ECMO. The improvement can be likely dependent on three main reasons: first, an increase of the endogenous surfactant pool; second, the reduction of lung injury by ventilation and exposition to high oxygen concentration; third, the modulation of inflammation process. The efficacy and safety suggested by the results of this study must be confirmed by further studies on a larger population, in order to develop more precise recommendations for therapy and dosages. Anyway, the treatment with surfactant is at present one of the most promising way for the therapy of MAS.

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