SHUNT AND VENTILATION-PERFUSION DISTRIBUTION DURING PARTIAL LIQUID VENTILATION IN HEALTHY PIGLETS

Replacing gas in the lung with perfluorocarbon fluids (PFC) and period ically ventilating with a gas [partial liquid ventilation (PLV)] has b een shown to improve oxygenation in models of respiratory distress syn drome. We hypothesized that the addition of PFC to healthy lungs would result in shunt, diffusion impairment, and increased ventilation-perf usion (VA/Q) heterogeneity. Previously, Mates et al. showed that O-2 s hunt and arterial-alveolar CO2 difference increased linearly with dose in piglets given graded intratracheal doses of PFC (10, 20, and 30 ml /kg followed by mechanical ventilation with 100% O-2) (E. A. Mates, J. C. Jackson, J. Hildebrandt, W. E. Truog, T. A. Standaert, and M. P. H lastala. In: Oxygen Transport to Tissue XVI, 1994, p. 427-435). Here w e report VA/Q distribution in the same animals, showing a 50% increase in VA/Q heterogeneity during PLV independent of PFC dose. Ventilation heterogeneity was the major factor in this increase, and there was no significant change in dead space ventilation. We also report on five animals given a single 20 ml/kg dose of PFC and followed for 3 h. They showed an increase in shunt during PLV but no change in arterial-alve olar CO2 difference.