HIGH-FREQUENCY OSCILLATORY VENTILATION WITH PARTIAL LIQUID VENTILATION IN A MODEL OF ACUTE RESPIRATORY-FAILURE

Objective: To determine whether there is an improvement in oxygenation when partial liquid ventilation and high-frequency oscillatory Ventil ation are combined in the treatment of acute lung injury, compared wit h high-frequency oscillatory ventilation alone. Design: Controlled ani mal trial. Setting: Research laboratory in a university setting. Subje cts: Ten 3-kg piglets. Interventions: Anesthetized piglets underwent h igh-frequency oscillatory ventilation, with mean airway pressure of 20 cm H2O, before induction of acute lung injury with repeated saline la vage. When Pao(2) values were <100 torr (<13.3 kPa), five animals were randomized to receive escalating doses (3, 15, and 30 mL/kg) of perfl ubron at 60-min intervals. The other five animals remained on high-fre quency oscillatory ventilation only. sham dosing was performed at 60-m in intervals in these animals. Arterial blood gases were obtained in b oth groups at baseline, after injury, and after perflubron and sham do ses. Measurements and Main Results: Statistically significant improvem ents in oxygenation were demonstrated in animals that received 3 mL/kg of perflubron with high-frequency oscillatory ventilation compared wi th animals receiving high-frequency oscillatory ventilation alone (253 +/- 161 vs. 90 +/- 30 torr [33.65 +/- 21.46 vs, 12.0 +/- 4.0 kPa], p <.05). Improvements in oxygenation with additional administration of p erflubron were not greater than the improvements seen in the high-freq uency oscillatory ventilation-only group. Paco(2) and pH were similar in both groups at all times. No hemodynamic compromise occurred in eit her group of animals. Conclusions: The combination of low-dose perflub ron with high-frequency oscillatory Ventilation leads to more rapid im provement in arteria[ oxygenation than high frequency oscillatory vent ilation alone, in a piglet model of acute lung injury. Although the gr oup receiving high-frequency oscillatory ventilation alone eventually achieved Pao(2) values that were equivalent to the group receiving hig h-frequency ventilation and perflubron, the combination of perflubron with high-frequency oscillatory ventilation may permit effective oxyge nation and ventilation at lower mean airway pressures by facilitating alveolar expansion and decreasing intrapulmonary shunt.