Abstract 88: Alterations in Pulmonary Vasoreactivity Following Lung Contusion in Rats

Abstract

Lung contusion, a common complication of blunt chest trauma is an independent risk factor for ALI/ARDS. Using a recently described rat model for isolated bilateral lung contusion from blunt chest trauma (Anesth Analg 2005;101:1482), studies suggested an inconsistent correlation between the extent of inflammation and hypoxia. We set out to investigate the alteration in pulmonary arterial (PA) reactivity in lung contusion. Methods: Lung contusion was induced in anesthetized spontaneously breathing adult male rats by dropping a hollow aluminum cylindrical weight (300 g) onto the chest with a protective shield placed on the precordium. Rats were allowed to recover and sacrificed at 4h and 24h (n=6 –9) and compared to uninjured controls. Third generation PA rings were dissected and placed in a bath with modified Krebs solution, connected to a transducer and bubbled with 21% O2+ 6% CO2. Some rings were pretreated with a non-specific NO synthase (NOS) inhibitor, L-nitro arginine (LNA 10−3 M). Rings were constric...