The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

SURFACTANT WITH PARTIAL LIQUID VENTILATION IMPROVES LUNG PATHOLOGY IN AN ANIMAL MODEL OF IRDS.

Patricia A. Meyers RRT, Jeanne D. Mrozek MD. Kendra M. Smith MD, Susan C. Simonton MD, John E. Connett PhD, Dennis R. Bing RRT, Mark C. Mammel MD. Infant Pulmonary Research Center, Children's Health Care-St. Paul, Minnesota and Depts. of Pediatrics and Biostatistics, University of Minnesota

Introduction: Partial liquid ventilation (PLV) with perflubron (LiquiVent(R)) in neonates is currently being studied in many centers. Does the administration of exogenous surfactant (Survanta(R)) with PLV dramatically change the pathology of the lung with IRDS? In this study, histologic and morphometric analysis were performed on a neonatal lung injury animal model following surfactant and PLV administration. Method: 32 newborn piglets (1.51±0.38 kg) were sedated, intubated and ventilated with tidal volume of 15 cc/kg. We induced lung injury with repeated saline lavage, defined as PaO2 < 60 torr at FiO2 1.0, with a reduction of lung compliance by 30%. The piglets were randomized into 4 groups and treated for 2 hours with: 1) surf only (S; n=8); 2) PLV only (PLV; n=8); 3) PLV followed by surf (PLV-S; n=8 and 4) surf followed by PLV (S-PLV; n=8). 7 histologic variables (alveolar and interstitial inflammation and hemorrhage, edema, atelectasis and necrosis) were scored on a 0-4 point scale (no injury = 0, injury in 25% of field = 1, injury in 50% of field = 2, injury in 75% of field = 3, and injury throughout field = 4). Morphometric analysis on trichrome-stained slides analyzed total cellular to air space, expressed as percent tissue area (% tissue area = [cellular area/total area] X 100). Kruskal-Wallis, Wilcoxin, and paired t-tests with Bonferroni correction (p < 0.05) were used to assess differences.

Histology Morphometrics

Total injury score Mean % tissue area

upper lower upper lower

S 4.75±2.30* 5.20±2.10** 46.5±8.3{?} 45.2±8.1{??}

PLV 4.55±2.15 2.50±1.30 39.0±8.7 30.9±7.8

PLV-S 3.90±1.65 2.85±2.00 35.9±6.4 30.0±7.6

S-PLV 2.65±1.10 2.65±1.30 33.9±8.2 30.0±6.

*p < 0.05 S vs S-PLV; **p < 0.05 S vs all; {?}p < 0.03 S vs PLV-S, S-PLV; {??}p < 0.002 S vs all

Conclusion: In this animal model of neonatal RDS, surf followed by PLV improved lung pathology more consistently than PLV or surf alone, or PLV followed by surf. (Liquivent(R) supplied by Alliance Pharmaceutical Corp. and Hoechst Marion Roussel; Survanta(R) supplied by Ross Laboratories, Inc.)

OF-97-094

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