The Science Journal of the American Association for Respiratory Care

1997 OPEN FORUM Abstracts

PARTIAL LIQUID VENTILATION WITH SURFACTANT DURING HIGH FREQUENCY AND CONVENTIONAL VENTILATION IN AN ANIMAL MODEL OF IRDS.

Dennis Bing RRT, Jeanne Mrozek MD, Patricia Meyers RRT, John Connett PhD, Mark Mammel MD. Infant Pulmonary Research Center. Children's Health Care-St. Paul, Minnesota and Depts. of Pediatrics and Biostatistics. University of Minnesota

We compared oxygenation effects of high frequency oscillatory ventilation (HFOV: SensorMedics 3100) and conventional ventilation (CV: Drager Babylog) in 19 newborn piglets (1.78 ± 0.12 kg) with saline lavage-induced lung injury (PaO2 < 60 torr at FiO_{2} 1.0 and 30% decrease in C_{1}) treated with surfactant (S: Survanta(R)) and partial liquid ventilation (PLV: LiquiVent(R)). After lung injury, piglets randomly received either HFOV (n=10) or CV (n=9). Ventilator settings after lung injury for the HFOV group: FiO_{2} 1.0, frequency of 10 Hz, [delta]P to maintain injury level PCO_{2}, mean airway pressure (Paw) 2 cm H_{2}O more than previous on CV, and CV group: FiO_{2} 1.0, IMV 40/ min., PEEP 4 cm H_{2}O, V_{T} 15 mL/kg. All animals then received 4 mL/kg of S. 30 minutes later, perflubron was intratracheally instilled to FRC level. At 1 hr, PEEP and Paw were increased until there was no further increase in PaO_{2}. After optimizing Paw, we maintained PaO_{2} 100-150 torr by first decreasing FiO_{2} to as low as 0.4, then lowering Paw or PEEP and kept PaCO_{2} 35-50 torr. We recorded arterial blood gases every 30 minutes for 4 hours Results: Oxygenation improved with CV after S and with HFOV only after S followed by PLV. Data are mean ± SE. ANOVA and paired t-tests assessed differences (p < 0.05).

CV group HFOV group

Paw a/A OI Paw a/A OI

Before 6.5±0.2 0.81±0.03 1.2±0.1 6.8±0.2 0.81±0.03 1.3±.1 injury

After 13.9±0.4* 0.08±0.01* 26.8±0.9* 14.1±0.7* 0.07±0.01* 33.0±3.8* injury

On CV/ 13.9±0.4 0.08±0.01?? 26.8±0.9? 15.8±1.1 0.08±0.01 35.4±5.0 HFOV

After 12.4±0.5 0.42±0.07 8.6±3.1 15.2±1.3 0.09±0.01 27.8±3.4

S [delta] [delta]

S+PLV 12.3±0.4 0.42±0.07 6.9±1.9 15.9±1.0 0.23±0.06? 15.9±2.8

[delta] [delta] [delta]

at 4 12.8±0.9 0.45±0.02 4.8±0.9 17.0±1.2 0.52±0.05 6.1±0.7

hours [delta]

*p < 0.05 before vs after injury [delta]p < 0.05 CV vs HFOV {?}p < 0.005 after S vs S+PLV (HFOV)

{??}p < 0.05 after S vs On CV

Conclusions: Surfactant and PLV during both CV and HFOV dramatically improves oxygenation in this neonatal RDS model; however, HFOV requires a higher Paw for similar effect. Initial surfactant response may be different between the two modes of mechanical ventilation. (LiquiVent(R) supplied by Alliance Pharmaceutical Corp. and Hoechst Marion Roussel. Survanta(R) supplied by Ross Laboratories, Inc.)

OF-97-095

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