晕厥是由于一时性广泛脑缺血、缺氧所致的短暂性意识及姿势肌张力丧失,在发生意识丧失前常伴有面色苍白、恶心、呕吐、头晕眼花、黑朦、出冷汗、脉弱、血压低等症,自我感觉似头重脚轻。 Syncope is due to a temporary generalized cerebral ischemia, hypoxia caused by transient consciousness and posture loss of muscle tension, loss of consciousness in the event often accompanied by pale, nausea, vomiting, dizziness, darkness, cold sweat, weak pulse , Low blood pressure disease, self-esteem seems top-heavy.