Secretory phospholipase A(2) pathway during pediatric acute respiratory distress syndrome: A preliminary study

Objective: To verify if secretory phospholipase A(2) (sPLA(2)) is increased in pediatric acute respiratory distress syndrome (ARDS) triggered or not by respiratory syncytial virus infection and to clarify how the enzyme may influence the disease severity and the degree of ventilatory support. Design: Prospective pilot study. Setting: Two academic pediatric intensive care units. Patients: All infants <6 months old hospitalized for severe respiratory syncytial virus bronchiolitis, who developed ARDS (respiratory syncytial virus-ARDS group); all infants <6 months old diagnosed with ARDS secondary to other causes (ARDS group); and infants <6 months old who needed ventilation for reasons other than any lung disease (control group). Interventions: None. Measurements and Main Results: We enrolled six respiratory syncytial virus -ARDS babies, five ARDS babies, and six control infants. The sPLA2 activity and tumor necrosis factor (TNF)-alpha were significantly higher in the bronchoalveolar lavage of ARDS infants. Worst oxygenation, ventilation, and longer pediatric intensive care unit stay and ventilation time were present in ARDS babies. No differences were found in Clara cell secretory protein and in serum cytokines levels. Because there is no correlation between bronchoalveolar lavage protein content (a marker of permeability) and sPLA(2), the enzyme seems mainly produced in the alveoli. TNF-alpha, the main inductor of sPLA(2) expression, significantly correlates with the enzyme level in the bronchoalveolar lavage. Significant positive correlations exist between sPLA(2), TNF-alpha and oxygen need, mean airway pressure, ventilatory index, and the Murray's lung injury score. Negative correlations were also found between sPLA(2), TNF-alpha, and PaO2/FIO2 ratio. Conclusions: The sPLA(2) and TNF-alpha are increased in ARDS and seem correlated with clinical severity, higher oxygen requirement, and more aggressive ventilation. This correlation confirms findings from adult experience and should guide further investigations on pediatric ARDS pathophysiology. (Pediatr Crit Care Med 2011; 12:e20-e24)