Total Liquid Ventilation Provides Superior Respiratory Support to Conventional Mechanical Ventilation in a Large Animal Model of Severe Respiratory Failure

Abstract

Total liquid ventilation (TLV) has the potential to provide respiratory support superior to conventional mechanical ventilation (CMV) in the acute respiratory distress syndrome (ARDS). However, laboratory studies are limited to trials in small animals for no longer than 4 hours. The objective of this study was to compare TLV and CMV in a large animal model of ARDS for 24 hours. Ten sheep weighing 53 ± 4 (SD) kg were anesthetized and ventilated with 100% oxygen. Oleic acid was injected into the pulmonary circulation until PaO2:FiO2 ≤ 60 mm Hg, followed by transition to a protective CMV protocol (n = 5) or TLV (n = 5) for 24 hours. Pathophysiology was recorded, and the lungs were harvested for histological analysis. Animals treated with CMV became progressively hypoxic and hypercarbic despite maximum ventilatory support. Sheep treated with TLV maintained normal blood gases with statistically greater PO2 (p < 10(-9)) and lower PCO2 (p < 10(-3)) than the CMV group. Survival at 24 hours in the TLV and CMV groups were 100% and 40%, respectively (p < 0.05). Thus, TLV provided gas exchange superior to CMV in this laboratory model of severe ARDS.