Otsuji Yutaka
Second Department of Internal Medicine, University of Occupational and Environmental Health, Japan, Yahatanisi-ku, Kitakyushu 807-8555, Japan.
J UOEH. 2008 Dec 1;30(4):431-42. doi: 10.7888/juoeh.30.431.
Hypotension and shock can be classified as hypotension caused by reduced or maintained left ventricular (LV) ejection. Reduced left ventricular ejection can result from intrinsic left ventricular, aortic valve or mitral valve failure, which includes dilated or ischemic cardiomyopathy, left main trunk disease, acute myocarditis, etc. Acute and subacute severe aortic regurgitation can also cause shock. Echocardiography allows noninvasive diagnosis of infective endocarditis and Takayasu's arteritis to cause severe arotic regurgitation and can also be used to diagnose obstruction of the left ventricular outflow tract. Reduced left ventricular preload can be caused by pericardial effusion and right ventricular ejection failure, and can result from pulmonary embolism, tricuspid regurgitation, right ventricular infarction, tension pneumothorax, hypovolemia and others characterized by a small left ventricle with good ejection fraction. Normal left ventricular ejection may be associated with hypotension. Sepsis, anaphylactic shock and neural disorder are associated with hypotension and normal cardiac output. Pseudohypotension may result from aortic dissection, Takayasu's arteritis, arteriosclerosis obliterans and aortic coarctation. A right parasternal approach enables better visualization of the ascending aorta. Fundamental echochocardiographic scanning allows approximate yet useful diagnosis of hypotension and shock.
低血压和休克可分为因左心室（LV）射血减少或维持所致的低血压。左心室射血减少可由左心室本身、主动脉瓣或二尖瓣功能衰竭引起，包括扩张型或缺血性心肌病、左主干病变、急性心肌炎等。急性和亚急性重度主动脉瓣反流也可导致休克。超声心动图可对感染性心内膜炎和大动脉炎进行无创诊断，这些疾病可导致严重的主动脉瓣反流，还可用于诊断左心室流出道梗阻。左心室前负荷降低可由心包积液和右心室射血衰竭引起，也可由肺栓塞、三尖瓣反流、右心室梗死、张力性气胸、血容量不足等导致，其特征为左心室小但射血分数良好。正常左心室射血可能与低血压相关。脓毒症、过敏性休克和神经功能障碍与低血压及正常心输出量相关。假性低血压可能由主动脉夹层、大动脉炎、闭塞性动脉硬化和主动脉缩窄引起。右胸骨旁入路能更好地观察升主动脉。基本的超声心动图扫描可对低血压和休克做出大致但有用的诊断。
