The Science Journal of the American Association for Respiratory Care

1995 OPEN FORUM Abstracts

Time Course Of Blood Gas And Lung Compliance Changes During Partial Liquid Ventilation In An Animal Model

Dennis R. Bing, RRT, Kendra M. Smith, MD, Raye Ann deRegnier, MD, Pat A. Meyers, RRT, Stephen J. Boros, MD, Mark C. Mammel, MD. Infant Pulmonary Research Center, Children's Health Care - St. Paul.

Partial liquid ventilation (PLV) using perfluorocarbons has been shown to rapidly improve oxygenation in animals and humans with severe lung disease. However, the time course of this change has not been reported. We evaluated the rate of blood gas and lung compliance (CI) changes during the first 30 minutes of PLV with preoxygenated perfluorocarbon (LiquiVent^{TM}, Alliance Pharm. Corp.) in a neonatal lung injury model. We induced lung injury (PaO2< = 60 torr, FiO2 1.0) with multiple saline lavage in 36 newborn piglets, then instilled an intratracheal volume of LiquiVent^{TM} to approximate FRC (30-50 ml/kg) by observing ET tube meniscus. Animals received ventilation using the Dr/ager Babylog ventilator at constant tidal volumes, PEEP, FiO2 and frequency. We measured arterial blood gases after lavage (before PLV), and at 5, 10, 15, and 30 minutes of PLV. We also measured dynamic and static CI after lavage and at 30 min. after PLV. Data were analyzed using one way ANOVA or paired t- tests, as appropriate. Post- hoc testing used Newman- Keuls multiple range analysis.

pHPCO2 PO2CI (dyn) CI (static)Paw

before PLV 7.11±0.1571±2348±10 0.60±0.20.65±0.311.6±1.4

5 min 7.15±0.1364±15154±101*

10 min7.17±0.1263±17171±106

15 min7.20±0.1057±11* 204±106

30 min7.26±0.10* 52±13253±113+ 0.92±0.2* 0.86±0.3* 10.6±2.7*

*p < 0.05 vs before PLV; *p < 0.01 vs before PLV; +p < 0.01 vs 5 min.

All parameters improved over the study period, in spite of a significant fall in Paw (p < 0.05). Arterial PO2 improved most rapidly, then continued to gradually increase. PCO2 improved more slowly, but was significantly lower at 15 minutes and sustained at 30 minutes. Changes in pH were significant at 30 minutes.

Conclusions: PLV rapidly improves lung mechanics and gas exchange, resulting in decreased pressure requirements to maintain tidal volumes.

OF-95-053

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