Albumin Mixed with Meconium Attenuates Pulmonary Dysfunction in a Newborn Piglet Model with Meconium Aspiration

Abstract

We hypothesized that lipids and bile acids in meconium may induce pulmonary insufficiency in newborns. Because albumin may bind these components we studied the effect of albumin on meconium-induced lung injury in piglets. We measured concentration of FFA in the meconium (110 mg dry weight/mL) and added albumin to provide a molar FFA to albumin ratio of 1:1. Newborn piglets, 0-2 d of age, artificially ventilated and exposed to hypoxemia by ventilation with 8% O2, were randomized to group A receiving meconium (n = 12) or group B receiving meconium + albumin (n = 12), 3 mL/kg intratracheally. The animals were reoxygenated for 8 h. Reoxygenation was started when mean blood pressure was <20 mm Hg or base excess was <-20 mM. Pulmonary function was assessed in parallel with pulmonary hemodynamics. From the start of reoxygenation and the next 8 h we found a significant difference (by ANOVA) between the two groups in oxygenation index (p = 0.005), with an increase from 1.6 +/- 0.2 to 6.1 +/- 6.8 (p = 0.04) in the meconium group and from 1.8 +/- 0.3 to 3.1 +/- 3.1 (NS) in meconium + albumin group. There were also significant differences (by ANOVA) between the groups in favor of the treatment group concerning need of inspired fraction of O2, mean airway pressure, dynamic compliance of the respiratory system, time constant, ventilation index, and pulmonary vascular resistance. In conclusion, albumin given concurrently with meconium significantly reduced detrimental effects of meconium aspiration in the lungs of newborn piglets.

Meconium Induced IL-8 Production and Intratracheal Albumin Alleviated Lung Injury in Newborn Pigs

“…On the contrary, we found an increase rather than reduction in dynamic lung compliance in the piglets receiving both meconium and albumin compared with those receiving meconium and saline. Our findings are in agreement with previous in vivo studies from our group show- ing that adding albumin to meconium before instilling it as an intratracheal bolus reduces pulmonary insufficiency (29). Albumin may inactivate surfactant inhibitors in meconium by binding them (26,29), and further it is conceivable that an interaction between albumin and other surfactant inhibitors in meconium abolishes the potential inhibition of albumin, as well.…”

“…We have recently shown that albumin attenuates pulmonary dysfunction in experimental MAS when it is mixed with meconium before instillation (29). This may be due to the high binding affinity of albumin for fatty acids and bilirubin (30).…”

Toxic effects of different meconium fractions on lung function: new therapeutic strategies for meconium aspiration syndrome?

“…In this study meconium was also mixed with albumin (30% albumin in stoichiometric relation to FFA estimated to be 1.4 ml kg À1 ) before intratracheal in administration of the mixture. 12,13 In the second study 3 ml kg À1 body weight of either meconium, lipid-or water-soluble meconium fractions was instilled intratracheally in separate groups. 14 In the third study a moderate and severe model was developed.…”

“…The need for oxygen and mean airway pressure on the ventilator was also significantly reduced and compliance increased in animals given the combination of meconium and albumin. 12 The inflammatory cytokine interleukin (IL)-8 in tracheal aspirate, 8 h after reoxygenation was started, was in mean fivefold higher (P<0.05) in animals given meconium alone (93 pg ml À1 ) as compared to those given meconium mixed with albumin (18 pg ml À1 ) before intratracheal instillation. 13 …”

Constrictor Action of Substances in the Pulmonary Artery in Newborn with the Amnional Fluid Aspiration Syndrome (MAS)

“…vitro" with meconium react with hyper-reactivity; whilst at tracheal segments in pre-contracted rat presence of meconium is associated with the relaxation of smooth musculature of these segments [18,19].…”