Changes of upper gastrointestinal blood flow after hemorrhage in rabbits

The effect of hemorrhage and blood transfusion on the regional blood flow of the upper gastrointestinal tract was measured with radioactive microspheres in a rabbit shock model. Fifteen minutes after hemorrhage, mucosal blood flow in the esophagus, corpus, and antrum and total blood flow in the duodenum decreased drastically. The persistent reduction of mucosal blood flow continued until 60 minutes after hemorrhage. In spite of these distribution patterns of mucosal blood flow during hemorrhage, no macroscopic change was seen in any part of the gastrointestinal mucosa. One hour after blood reinfusion, the mucosal blood flow in the corpus was increased markedly, and innumerable hemorrhagic erosions appeared in this region. It may be that the striking increase of mucosal blood flow due to blood transfusion caused bleeding from the disrupted mucosa of the corpus. At this time the impaired flow in the esophagus, antrum, and duodenum tended to be improved already. Six hours after blood reinfusion, the bleeding from the mucosal foci in the corpus ceased and the mucosal blood flow returned to almost normal. Thus the higher susceptibility of the corpus to hemorrhagic shock may be due to the greater degree of rapid increase of mucosal blood flow occurring in this portion alone after blood transfusion as well as to its higher vulnerability to ischemia in the hemorrhagic period. The flow patterns in the muscular layer almost paralleled those in the mucosal layer during hemorrhage and blood transfusion.