We examined the effects of
dexamethasone on lung function in a piglet model of
meconium aspiration syndrome. We induced
lung injury in 10 newborn piglets (age 5 +/- 0.2 d) with 4 mL/kg
body weight of 20% sterile human meconium in
normal saline given via
tracheostomy.
Ventilator management was aimed at maintaining comparable values of end tidal
carbon dioxide, Hb saturation, and arterial blood
gases. Lung function was assessed using a BICORE CP100 neonatal monitor. Five piglets received 0.5 mg/kg of
dexamethasone 2 and 8 h after meconium administration, whereas control piglets received
normal saline at similar times.
Ventilator settings,
oxygen requirements, and lung compliance were similar between groups at the start of the study. Two hours after the instillation of meconium, there was marked lung dysfunction in both groups as evidenced by increased
oxygen requirements [fraction of inspired
oxygen (FiO2) 0.98 +/- 0.01 versus FiO2 0.21 +/- 0, p < 0.0001] and reduced lung compliance (0.35 +/- 0.03 versus 0.8 +/- 0.03 mL x kg(-1) x cm(-1) H2O, p < 0.0001). Administration of
dexamethasone resulted in lower
oxygen requirements (FiO2 0.27 +/- 0.01 versus FiO2 1.0 +/- 0.0, p < 0.00001), lower oxygenation index (2.17 +/- 0.17 versus 22.64 +/- 3.39, p < 0.0001), ventilatory efficiency index (0.30 +/- 0.01 versus 0.07 +/- 0.01, p < 0.0001), and improved lung compliance (0.68 +/- 0.04 versus 0.34 +/- 0.05 mL x kg(-1) x cm(-1) H2O, p < 0.001) compared with the control group. In summary, a two-dose course of 0.5 mg/kg of
dexamethasone improved blood
gases and lung function in a piglet model of
meconium aspiration syndrome.