Effect of high doses of aspirin on pulmonary hemodynamics and lung water.

The purpose of this study was to determine if aspirin, in doses that elevate plasma salicylate concentrations to values reported in patients with salicylate-induced pulmonary edema, produce pulmonary vasoconstriction in a canine, isolated perfused left lower lung lobe (LLL) preparation. In 10 LLL's, aspirin (avg 97.8 mg/dl plasma) caused LLL arterial pressure to rise from 9.1 +/- 0.3 to 23.0 +/- 1.8 (SE) Torr. In contrast, no vascular pressure changes were observed in placebo-treated control LLL's. Sodium meclofenamate and indomethacin, structurally dissimilar cyclooxygenase inhibitors, elicited similar responses to aspirin, suggesting that a mechanism involving products of prostaglandin cyclooxygenase was involved in producing the vasoconstriction. The double-occlusion technique was used to localize the sites of the vasoconstriction. The results suggested that all three drugs caused both lobar arterial and venous tone to increase. Although high doses of aspirin produced pulmonary vasoconstriction in the isolated, perfused LLL, the aspirin-treated LLL's gained less weight and extravascular water than the control lobes.