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Surfactant kinetics in preterm infants on mechanical ventilation who did and did not develop bronchopulmonary
Paola E Cogo1, Luc J I Zimmermann, Roberta Pesavento
1Department of Pediatrics, University of Padova, Italy.
Insights
Premature infants on mechanical ventilation who developed bronchopulmonary dysplasia had altered surfactant kinetics, including reduced surfactant concentration and shorter half-life. These changes correlated with the severity of ventilatory support.
Area of Science:
- Neonatal Physiology
- Pulmonary Medicine
- Biochemistry
Background:
- Bronchopulmonary dysplasia (BPD) is a significant complication in premature infants requiring mechanical ventilation.
- Surfactant plays a crucial role in lung function and its kinetics may be altered in infants with BPD.
- Understanding surfactant kinetics can provide insights into BPD pathogenesis and inform treatment strategies.
Purpose of the Study:
- To characterize in vivo surfactant kinetics in premature infants with varying levels of mechanical ventilation.
- To compare surfactant kinetics between infants who developed BPD and those who did not.
- To investigate the correlation between surfactant kinetics and the severity of mechanical ventilation.
Main Methods:
- A controlled observational study was conducted in a neonatal intensive care unit.
- Two groups of preterm infants were studied: those on high mechanical ventilation who developed BPD (MechVentBPD) and those with minimal lung disease who did not develop BPD (MechVentNoBPD).
- 13C-labeled dipalmitoyl-phosphatidylcholine was administered, and surfactant-disaturated phosphatidylcholine (DSPC) enrichment in tracheal aspirates was measured using gas chromatography-mass spectrometry to determine pharmacokinetic variables like half-life and pool size.
Main Results:
- Infants in the MechVentBPD group had significantly reduced epithelial lining fluid DSPC concentration (2.9 vs. 9.4 mg/mL ELF) and a shorter half-life (19.4 vs. 42.5 hrs) compared to the MechVentNoBPD group.
- The apparent DSPC pool size was larger in MechVentBPD infants (136 vs. 65.8 mg/kg).
- In MechVentBPD infants, DSPC pool size correlated positively with mean airway pressure x Fio(2) and inversely with ELF-DSPC, while ELF-DSPC inversely correlated with mean airway pressure x Fio(2).
Conclusions:
- Premature infants who develop BPD exhibit profound alterations in surfactant kinetics compared to those with minimal lung disease.
- These alterations in surfactant kinetics are significantly correlated with the severity of mechanical ventilatory support.
- The findings suggest that abnormal surfactant dynamics contribute to the development or progression of BPD in mechanically ventilated preterm infants.
Objective:
To characterize surfactant kinetics in vivo in two groups of premature infants on different levels of mechanical ventilation and at different risk of developing bronchopulmonary dysplasia.
Design:
Controlled observational study in two independent groups of infants.
Setting:
Neonatal intensive care unit.
Patients:
Thirteen preterm infants (26 +/- 0.5 wks, birth weight 801 +/- 64 g) on high ventilatory setting and who finally all developed bronchopulmonary dysplasia (MechVentBPD), and eight (26 +/- 0.5 wks, birth weight 887 +/- 103 g) who had minimal or no lung disease and of whom none developed bronchopulmonary dysplasia (MechVentNoBPD).
Measurements And Main Results:
Endotracheal 13C-labeled dipalmitoyl-phosphatidylcholine was administered and subsequent measurements of the 13C enrichment of surfactant-disaturated phosphatidylcholine (DSPC) from serial tracheal aspirates were made by gas chromatography-mass spectrometry. We calculated disaturated phosphatidylcholine pharmacokinetic variables in terms of half-life and apparent pool size from the enrichment decay curves over time. DSPC concentration from tracheal aspirates was expressed as milligrams/milliliter epithelial lining fluid (ELF-DSPC). Data are presented as mean +/- se. In MechVentBPD infants vs. MechVentNoBPD, ELF-DSPC was much reduced, 2.9 +/- 0.6 vs. 9.4 +/- 3.0 mg/mL ELF (p =.03), half-life was shorter, 19.4 +/- 2.8 vs. 42.5 +/- 6.3 hrs (p =.002), and apparent pool size larger, 136 +/- 21 vs. 65.8 +/- 16.0 mg/kg (p =.057). In MechVentBPD, apparent DSPC pool size positively correlated with mean airway pressure x Fio(2) and inversely correlated with ELF-DSPC. ELF-DSPC was inversely correlated with mean airway pressure x Fio(2). No significant correlations were found in the MechVentNoBPD group.
Conclusions:
MechVentBPD infants showed profound alteration of surfactant kinetics compared with preterm infants with minimal lung disease, and these alterations were correlated with severity of ventilatory support.