Acute lethality after enteral administration of contrast media in anaesthetized rats with intestinal ischaemia

The acute lethality was evaluated during enteric follow-through in anaesthetized rats with a ligature applied to the anterior mesenteric artery and vein. In 121 animals 3 ml of either sodium diatrizoate, iohexol or barium sulphate was administered via orogastric tube. Alternatively, they had the oro-gastric tube inserted but no test substance instilled (controls). A total of 103 rats was observed until spontaneous death while 18 were sacrificed after 8 hours of observation. The survival time in the sodium diatrizoate group was significantly shorter than for the other three groups (p less than 0.006). The 50% survival time was 5 h 42 min (range 2 h 48 min to 12 h 45 min) for sodium diatrizoate as compared with 8 h 4 min to 8 h 26 min for the other three groups; iohexol 8 h 4 min (range 2 h 4 min to 14 h 43 min), barium 8 h 13 min (range 4 h 55 min to 16 h 26 min) and no instilled substance 8 h 26 min (range 3 h 38 min to 16 h 10 min) with no significant differences between these 3 groups. The use of hyperosmolar contrast media in enteric follow-through significantly shortens the survival of rats with acute intestinal ischaemia. A more rapid spread of intestinal bacteria through the distended bowel wall and the ensuing septicaemia, accompanied by enhanced dehydration, are probably the mechanisms responsible for the earlier deaths.