Treatment of experimental meconium aspiration syndrome with surfactant lung lavage and conventional vs. asymmetric high‐frequency jet ventilation

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Abstract
Respiratory failure caused by meconium aspiration requires combined strategies. We hypothesized that surfactant lung lavage with asymmetric high‐frequency jet ventilation (AHFJV) can increase the removal of meconium and improve lung function. During conventional ventilation (CV), a suspension of human meconium (25 mg/ml, 4 ml/kg) was instilled into the tracheal tube of anesthetized rabbits to cause respiratory failure. Animals were then divided into four groups: saline lavage + CV (Sal‐CV), surfactant lavage + CV (Surf‐CV), saline lavage + HFJV (Sal‐HFJV), and surfactant lavage + HFJV (Surf‐HFJV). Lung lavage (10 ml/kg in 3 portions) was performed with diluted surfactant (Curosurf, 100 mg of phospholipids/kg) or saline during CV (frequency (f), 30/min; inspiration time (Ti), 50%) or AHFJV (f, 300/min; Ti, 70%). Animals were ventilated for an additional hour with either CV or HFJV (Ti, 50%). Surfactant lavage with both CV and AHFJV removed more meconium than saline lavage. However, the highest removal was found in the Surf‐HFJV group vs. all other groups (P < 0.05). The oxygenation index decreased after surfactant lavage in both groups compared to controls (P < 0.001), and more prominently in the Surf‐CV group. Elimination of CO2 was significantly higher in the Surf‐HFJV group vs. all other groups (P < 0.05). The ventilation efficiency index increased after lavage in both surfactant groups vs. saline controls (P < 0.05). Dynamic lung‐thorax compliance gradually increased, and right‐to‐left pulmonary shunts decreased in both surfactant groups vs. saline controls after lavage (P < 0.05). Combination of surfactant lavage with both CV and AHFJV was beneficial in rabbits with meconium aspiration syndrome. While AHFJV was more effective in the removal of meconium, CV had a more favorable effect on lung function in the postlavage period. Pediatr Pulmonol. 2004; 38:285–291.