RESUMO
Surfactant indices and inhibitors were measured in lung lavage fluid from 8 infants with meconium aspiration syndrome (MAS) who were receiving mechanical ventilation and 11 healthy control subjects. Surfactant phospholipid and surfactant protein A content in MAS was not different from that of control subjects, but concentrations of total protein, albumin, and membrane-derived phospholipid were elevated. All infants with MAS had hemorrhagic pulmonary edema. These findings reinforce the notion of MAS as a toxic pneumonitis with epithelial disruption and proteinaceous exudation.
Assuntos
Líquido da Lavagem Broncoalveolar/química , Síndrome de Aspiração de Mecônio/patologia , Surfactantes Pulmonares/antagonistas & inibidores , Surfactantes Pulmonares/análise , Albuminas/análise , Gasometria , Nitrogênio da Ureia Sanguínea , Estudos de Casos e Controles , Idade Gestacional , Hemorragia/etiologia , Humanos , Recém-Nascido , Síndrome de Aspiração de Mecônio/sangue , Síndrome de Aspiração de Mecônio/etiologia , Síndrome de Aspiração de Mecônio/terapia , Fosfolipídeos/análise , Volume Plasmático , Proteínas/análise , Proteolipídeos/análise , Edema Pulmonar/etiologia , Proteínas Associadas a Surfactantes Pulmonares , Respiração Artificial/métodos , Fatores de TempoRESUMO
Airway samples from infants with respiratory distress syndrome were recovered by suction immediately after tracheal intubation for respiratory failure. The minimum surface tension of these airway samples was 27.3 +/- 3.0 dynes/cm. Surfactant with low surface tension (1.4 +/- 1.0 dynes/cm) was recovered from these samples by centrifugation; the supernatant fractions from the samples had high minimum surface tensions. The supernatant fractions contained soluble proteins that inhibited the surface tension-lowering properties of natural sheep surfactant. Similar supernatant fractions collected from infants intubated for reasons other than respiratory distress syndrome were much less inhibitory to sheep surfactant. The minimum surface tension of sequential daily airway samples from infants with respiratory distress syndrome fell progressively to 5.7 +/- 2.4 dynes/cm on the day of extubation. These results document the presence of proteins in the airways of infants with respiratory distress syndrome that inhibit the surface tension-lowering properties of surfactant.