Partial liquid ventilation enhances surfactant phospholipid production.

ABSTRACT

OBJECTIVE: To study the effect of partial liquid ventilation on phospholipid metabolism. DESIGN: Prospective, controlled laboratory study. SETTING: University-affiliated animal research facility. SUBJECTS: Mature New Zealand white rabbits (n = 17). INTERVENTIONS: The rabbits were sedated, anesthetized, and instrumented with tracheostomy and the insertion of an arterial catheter. The rabbits were sequentially assigned to receive conventional mechanical ventilation or partial liquid ventilation with Perflubron (18 mL/kg by bolus fill). Ventilator strategies were identical in both groups and consisted of an FiO2 of 0.5, positive end-expiratory pressure of 4 cm H2O, effective tidal volume of 8 to 13 mL/kg, and rate to maintain Pco2 of 30 to 40 torr (4.0 to 5.3 kPa). Phosphatidylcholine was labeled in vivo by injection of 3H-methylcholine (25 microCi/kg iv). Ventilation was continued for 5.5 hrs. MEASUREMENTS AND MAIN RESULTS: When animals were killed, phosphatidylcholine was extracted from the total lung lavage and from the pulmonary parenchyma. After the separation of phospholipids by thin-layer chromatography, the 3H activity was determined by liquid scintillation counting. Inorganic phosphorus was also determined to assess the enrichment of the phosphatidylcholine. The 3H-phosphatidylcholine activity in the partial liquid ventilation treated- vs. control rabbits demonstrated a 53% increase (p = .051) in the lavage and a 48% increase (p = .013) in the parenchyma for a net 50% (p = .012) total pulmonary increase. The phospholipid content of the partial liquid ventilation treated- vs. the control rabbits demonstrated a 78% increase (p = .046). CONCLUSIONS: We conclude that partial liquid ventilation with Perflubron appears to have no negative impact on phospholipid metabolism but rather enhances surfactant phospholipid synthesis and secretion.