Physicochemical properties of perfluorochemical liquids influence ventilatory requirements, pulmonary mechanics, and microvascular permeability during partial liquid ventilation following intestinal ischemia/reperfusion injury.

Abstract

To test the hypothesis that the physicochemical properties of perfluorochemical liquid used in partial liquid ventilation can influence ventilatory requirements, pulmonary mechanics, microvascular permeability, and vasoactive mediator release in the abnormal lung. Prospective, controlled animal study. Research laboratory in a university setting. SUBJECTS Male Sprague-Dawley rats: sham and intestinal ischemia/reperfusion injury. Treatment with perfluorochemical partial liquid ventilation (PLV: PP-5 or H-130) or conventional mechanical ventilation (CMV) over 60 mins of superior mesenteric artery occlusion and 60 mins of reperfusion. Gas exchange, ventilatory requirements, and pulmonary mechanics were measured in vivo. Subsequently, pulmonary vascular resistance, microvascular permeability, and thromboxane were measured by using the isolated perfused lung preparation. PLV with PP-5 required significantly (p <.05) higher positive end-expiratory pressure resulting in increased mean airway pressures and pulmonary vascular resistance in both sham and intestinal ischemia/reperfusion injured animals compared with those treated with CMV or PLV H-130. PLV PP-5 also resulted in significantly (p <.05) lower respiratory compliance and greater microvascular permeability compared with sham animals. Following intestinal ischemia/reperfusion injury, PLV H-130 treated animals had significantly higher (p <.05) respiratory compliance than those treated with PLV PP-5 and a significantly lower (p <.05) intestinal ischemia/reperfusion-mediated increase in microvascular permeability than those treated with CMV or PLV PP-5. Thromboxane levels were significantly higher (p <.01) in injured animals treated with CMV or PLV PP-5 compared with comparably treated shams, were significantly lower (p <.01) in both PLV groups than CMV, and were further attenuated (p <.01) by PLV H-130 compared with PLV PP-5 animals. We conclude that PLV with perfluorochemical liquids attenuates pulmonary sequelae resulting from remote organ injury and that the extent of lung protection depends on the physicochemical properties of the perfluorochemical liquids.