缺血缺氧是医学临床上常见的一种严重病理过程,但其发生机制,至今未彻底阐明。近年发现组织损伤不但发生在缺血缺氧的当时,更重要的是发生在组织恢复血流之时。此时所引起的综合表现称为再灌流综合征(Reperfusion syndrome)。消化道大出血,一般是指在数小时内失血量超出1000ml或循环血量的20％。从而引起组织缺血缺氧,随后输血、补液等治疗可导致缺血再灌注损伤(Reperfusion Ischemia and hypoxia is a serious clinical pathological process common in medicine, but its mechanism has not been fully elucidated so far. In recent years, tissue damage not only occurred in the hypoxic-ischemic time, more importantly, occurs when the tissue to restore blood flow. At this time caused by the overall performance known as the reperfusion syndrome (Reperfusion syndrome). Gastrointestinal bleeding, generally refers to the amount of blood loss within 1000 hours or circulating blood volume of 20%. Resulting in tissue ischemia and hypoxia, followed by blood transfusion, fluid replacement therapy can cause ischemia-reperfusion injury (Reperfusion