Background: Severe impairment of lung functions in meconium aspiration syndrome (MAS) often needs the application of combined therapeutic approach. In our recent study, surfactant lung lavage during asymmetric high-frequency jet ventilation (HFJV) removed more meconium than surfactant lavage during conventional ventilation, however, after the lavage excessive CO2 elimination was observed during HFJV.
Objectives: We hypothesized that the combination of asymmetric HFJV during surfactant lung lavage and conventional ventilation in the post-lavage period may be of benefit in a rabbit model of MAS.
Methods: Suspension of human meconium in saline (25 mg/ml, 4 ml/kg) was instilled into the tracheal tube of conventionally ventilated (frequency, f, 30/min, inspiration time, Ti, 50%) anesthetized rabbits to cause a respiratory failure. Animals were then lavaged (10 ml/kg in 3 portions) with diluted surfactant (Curosurf, 100 mg of phospholipids/ml) or saline during asymmetric HFJV (f, 300/min, Ti, 70%). After the lavage, animals were ventilated conventionally (f, 30/min, Ti, 50%) for next 1 hour.
Results: Surfactant lung lavage during asymmetric HFJV removed more meconium pigments and solids than saline with HFJV (p < 0.05 or p < 0.01, respectively). Moreover, application of asymmetric HFJV facilitated the lavage fluid removal in both groups. In the post-lavage period, improved oxygenation, lung compliance, right-to-left pulmonary shunts, and reduced ventilatory requirements were found in the surfactant group (p < 0.05), while pCO2 was kept in the normal range.
Conclusions: Surfactant lung lavage by asymmetric HFJV followed by conventional ventilation is advantageous combination in rabbits with MAS and may be tested in neonatal MAS (Tab. 2, Fig. 2, Ref. 12).