Journal
AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY
Volume 287, Issue 5, Pages L992-L998Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajplung.00158.2004
Keywords
fetal organ maturity; lung compliance; oscillometry; respiratory mechanics
Categories
Funding
- NICHD NIH HHS [HD-12714] Funding Source: Medline
Ask authors/readers for more resources
Antenatal exposure to intra-amniotic (IA) endotoxin initiates a complex series of events, including an inflammatory cascade, increased surfactant production, and alterations to lung structure. Using the low frequency forced oscillation technique as a sensitive tool for measurement of respiratory impedance, we aimed to determine which factors contributed most to measured changes in lung mechanics. Respiratory impedance data obtained from sedated preterm lambs exposed to either IA injection with saline or 20 mg of endotoxin 1, 2, 4, and 15 days before delivery at 125 days gestation were studied, and association with indexes of standard lung morphometry, inflammatory response, and alveolar surfactant-saturated phosphatidylcholine (Sat PC) pool size was demonstrated. Reduction in tissue impedance with increasing interval between exposure and delivery was evident as early as 4 days after IA endotoxin injection, coinciding with resolution of inflammatory reaction, increased alveolar surfactant pools, and contribution of alveolar ducts to the parenchymal fraction, and a later decrease in the tissue component of the parenchymal fraction. Decreases in tissue damping (resistance) were more marked than decreases in tissue elastance. Log alveolar Sat PC accounted for most variability in tissue damping (88.9%) and tissue elastance (73.4%), whereas tissue fraction contributed 2 and 6.4%, respectively. The alveolar Sat PC pool size was the sole factor contributing to change in tissue hysteresivity. No changes were observed in airway resistance. Despite the complex cascade of events initiated by antenatal endotoxin exposure, variability in lung tissue mechanics is associated primarily with changes in alveolar Sat PC pool and lung morphology.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available