Purposes: Secretory phospholipase A2 hydrolyzes phosphoglycerides and it has been shown to be involved in alveolar inflammation and surfactant degradation. It plays an important role in acute lung injury but it has never been studied in newborn infants. We were aimed to investigate the phospholipase A2 activity in neonatal lung injury and its relationship with ventilatory findings.
Setting: Third level university hospital NICU.
Methods: We measured phospholipase activity in broncho-alveolar lavage fluid of 21 neonates with hyaline membrane disease, 10 with pneumonia or sepsis and 10 controls, ventilated for extrapulmonary reasons. Fluid was obtained before surfactant administration on the first day of life and phospholipase activity was measured using an ultrasensitive enzymatic method. Before lavage, lung mechanics in pressure controlled synchronized intermittent mandatory ventilation was analyzed.
Results: Phospholipase A2 was higher in babies ventilated for sepsis/pneumonia compared to hyaline membrane disease and to control babies. Phospholipase correlated negatively with dynamic compliance, positively with inspired oxygen fraction, mean airway pressure and oxygenation index. These correlations still remained significant after multivariate analysis, adjusting for possible confounding factors. Phospholipase was not correlated with blood and alveolar pH, gestational age, birth weight, blood gases, Apgar score, tidal volume, surfactant need and ventilation time.
Conclusions: These are the first data about phospholipase A2 in neonates. The enzyme plays a role in neonatal lung injury, especially in infection related respiratory failure. It is associated with lung stiffness, higher mean airway pressure and need for oxygen.