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Surfactant content in children with inflammatory lung disease
A M LeVine1, A Lotze, S Stanley
1Section of Critical Care Medicine, Children's National Medical Center, Washington, DC, USA.
Insights
Children with bacterial pneumonia, viral pneumonitis, and ARDS show abnormal tracheal aspirate surfactant profiles. Surfactant levels in cardiopulmonary bypass patients were similar to controls, indicating specific disease-related changes.
Area of Science:
- Pediatric Critical Care Medicine
- Pulmonary Surfactant Research
- Respiratory Physiology
Background:
- Respiratory failure in children necessitates mechanical ventilation.
- Tracheal secretions contain crucial biomarkers for lung health.
- Surfactant dysfunction is implicated in various pediatric respiratory conditions.
Purpose of the Study:
- To investigate surfactant profiles in tracheal aspirates of mechanically ventilated children.
- To compare surfactant composition across different causes of respiratory failure: bacterial pneumonia, viral pneumonitis, ARDS, and cardiopulmonary bypass.
Main Methods:
- Prospective cohort study involving 120 pediatric patients in a tertiary PICU.
- Tracheal aspirates collected serially from patients with diverse respiratory failure etiologies.
- Analysis of lecithin/sphingomyelin ratios and surfactant proteins A and B using HPLC and ELISA.
Main Results:
- Patients with bacterial pneumonia, viral pneumonitis, and ARDS exhibited altered lecithin/sphingomyelin ratios and reduced surfactant protein A on day 1.
- Significant differences in surfactant profiles were observed among diagnostic groups.
- Lower pulmonary compliance and higher oxygenation index correlated with abnormal surfactant findings in pneumonia, pneumonitis, and ARDS groups.
Conclusions:
- Abnormalities in tracheal aspirate surfactant phospholipids and surfactant protein A are characteristic of pediatric bacterial pneumonia, viral pneumonitis, and ARDS.
- Surfactant profiles in children undergoing cardiopulmonary bypass did not differ from controls.
- These findings highlight the diagnostic and potentially therapeutic relevance of surfactant analysis in pediatric respiratory failure.
Objective:
To determine surfactant profiles of tracheal secretions in mechanically ventilated children with respiratory failure secondary to bacterial pneumonia, viral pneumonitis, adult respiratory distress syndrome (ARDS), and cardiopulmonary bypass.
Design:
Prospective, cohort study.
Setting:
Tertiary, multidisciplinary, pediatric intensive care unit.
Patients:
One hundred twenty pediatric patients with respiratory failure requiring mechanical ventilation.
Interventions:
Routine tracheal aspirates were collected from children with bacterial pneumonia, viral pneumonitis, ARDS, postcardiopulmonary bypass, and a postsurgical control group. Samples were obtained on days 1, 2, 3, after every week of intubation and on the day of extubation.
Measurements And Main Results:
The tracheal aspirates were analyzed by high-performance liquid chromatography for lecithin/sphingomyelin rations and by enzyme-linked immunosorbent assay for surfactant proteins A and B. Lung compliance and the oxygenation index were measured on each day of sample collection. On day 1, patients with bacterial pneumonia, viral pneumonitis, and ARDS had decreased lecithin/sphingomyelin ration (p < .001), and those patients with bacterial pneumonia and viral pneumonitis had decreased surfactant protein A/protein concentration (p < .001). The lecithin/sphingomyelin ratios and surfactant protein A/protein concentration were significantly different among the groups (p < .001), with the bacterial pneumonia and viral pneumonitis groups having higher lecithin/sphingomyelin ratios and increased surfactant protein concentrations before extubation. Pulmonary compliance was lower and the oxygenation index was higher than controls (p < .001) in patients with bacterial pneumonia, viral pneumonitis, and ARDS. Pulmonary compliance was correlated weakly with lecithin/sphingomyelin ratio (r2 = .11, p < .001) and surfactant protein A/protein concentration (r2 = .03, p < .05). Surfactant protein B was similar in the diagnostic groups. Surfactant content in tracheal secretions from cardiopulmonary bypass patients was equivalent to controls.
Conclusion:
Abnormal tracheal aspirate surfactant phospholipids and surfactant protein A were noted in children with bacterial pneumonia, viral pneumonitis, and ARDS, but not in children on cardiopulmonary bypass.