Acute massive pulmonary embolism was induced in 94 random-bred dogs. There were 3 groups of the time control (0, 1 and 6 hrs) and 4 experimental groups (1- and 6-hrs compensated, 1- and 6-hrs decompensated). Favorable signs of the vascular adaptation: moderate arterial plasmorrhagia; lack of blood stasis, heterogeneity of metabolic profiles of arteries; prevalence of anaerobic glycolysis; some prevalence of catabolic reactions over anabolic reactions. Non-favorable signs: considerable plasmorrhagia; perivascular edema; multiple stases and hemorrhages; venous thrombosis; a dramatic decrease of the enzymatic activity in the arterial wall.