Objectives: 

Meconium aspiration syndrome (MAS) is a serious life-threatening condition with hypoxemic respiratory failure of newborns. Pathophysiology of MAS is complex and includes airway obstruction, dysfunction of pulmonary surfactant and local inflammation followed by formation of lung edema. Development of inflammatory processes may negatively affect benefit of the treatment by exogenous surfactant. Therefore, we tried to combine surfactant therapy with anti-inflammatory agent – glucocorticoid budesonide in an experimental model of MAS.

Materials: 

Oxygen-ventilated New Zealand white rabbits with meconium-induced respiratory failure were divided into 4 groups: without treatment (Mec), with surfactant treatment (Mec+Surf), with budesonide (Mec+Bud), and with combined surfactant and budesonide treatment (Mec+Surf+Bud). Blood gases, ventilatory pressures and other respiratory parameters were recorded before and after meconium instillation and 30 min, 1, 2, 3, 4, 5 hours after the treatment delivery. Oxygenation index (OI) was calculated as: OI=MAPxFiO2/PaO2. Right-to-left pulmonary shunts (RLS) were determined using the Fick equation. After sacrificing the animals, lung edema expressed as wet/dry weight (W/D) ratio was determined. Differences between the groups were compared with one-way ANOVA.

Results: 

Combined therapy (Mec+Surf+Bud) immediately improved PaO2 and OI in comparison with Mec and Mec+Bud groups (p<0.001 each) within 30 min of the therapy, whereas PaO2 and OI at 30 min (p<0.01) and PaO2 at 5 hours (p<0.05) were in Mec+Surf+Bud better than in Mec+Surf group. Surfactant-only therapy decreased both RLS and W/D ratio (both p<0.05 vs. Mec group), however, combined therapy showed more potent effect on these parameters (both p<0.01 vs. Mec group).

Conclusions: 

Combined surfactant and anti-inflammatory treatment can reduce lung edema, RLS and OI and result in effective and long-term lung function improvement in experimental model of MAS.

Supported by grants: CEPVII 26220120036, VEGA 1/0057/11, UK/466/2012