ACUTE PULMONARY INJURY IN A MODEL OF RUPTURED ABDOMINAL AORTIC-ANEURYSM

The purpose of this study was to determine whether the combined insult s of hemorrhagic shock and aortic clamping simulating ruptured abdomin al aortic aneurysm repair had a synergistic effect on the production o f pulmonary injury, indicating remote Organ injury. Methods: Animals w ere randomized to one of three groups, infrarenal clamp plus 1 hour of shock, infrarenal clamp plus 2 hours of shock, and supramesenteric cl amp plus 1 hour of shock. Each of these groups had four subgroups; sha m, shock (mean arterial pressure of 50 mm Hg), clamp, or combined [sho ck plus clamp]). Ah animals had a laparotomy with aortic clamping in o nly the clamp and combined groups. Five hours after clamp removal lung permeability index and neutrophil sequestration were quantified. Resu lts: Lung permeability index (6.60 +/- 0.63, p < 0.05 vs all other gro ups) and neutrophil sequestration (3.72 +/- 0.45 vs sham and clamp, p < 0.05) were significantly increased when shock and supramesenteric cl amp were combined. After 1 or 2 hours of shock and infrarenal clamping , no increase in lung permeability index was noted, although neutrophi l sequestration was increased in the 2-hour shock group. Conclusions: These results demonstrate the additive effect of shock and supramesent eric clamping, which initiated a cascade of injurious events that resu lted in a rapid pulmonary injury. The high mortality rate related to r emote organ failure in ruptured abdominal aortic aneurysm may be relat ed to the synergy of these two injurious processes.