Perfluorocarbon (PFC) Instillation Improves Oxygenation during Proportional Assist Ventilation (PAV) in Severely Surfactant-Depleted Spontaneously Breathing Rabbits

Abstract 89

Background: PAV, also known as resistive and elastic unloading, compensates for high airway resistance and low compliance, and thereby facilitates spontaneous breathing. We hypothesized that instillation of PFC would improve oxygenation in non-paralyzed surfactant deficient rabbits breathing spontaneously while assisted by PAV. Subjects: Sixteen anesthetized rabbits (median weight 2415g, range 2240-2930g)Interventions: After pulmonary lavage (target PaO₂ < 100 mmHg at a PEEP of 6 mbar and an FiO₂ of 1.0), the rabbits were randomized to PAV (PEEP of 8 mbar) with or without PFC. PFC rabbits received 25 ml/kg Rimar-101 by intra-tracheal infusion (1 ml/kg/min). PaO₂ and PaCO₂ were measured and evaporated PFC was refilled q 30 minutes. Mean airway pressure (MAP), expiratory minute ventilation (VE), respiratory rate (RR), heart rate (HR) and mean blood pressure (MBP) were recorded continuously for 5 hours. Results: PaO₂ was significantly higher in the PLV rabbits compared to controls (p<0.05, RM ANOVA). All other parameters were similar in both groups(table, medians and 25th - 75th percentile). Conclusion: PFC instillation improves oxygenation in spontaneously breathing severely surfactant depleted rabbits supported by PAV.

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