Evaluation of intraoperative hypotension by transesophageal echocardiography (TEE)

TEE: transesophageal echocardiogram; LV: left ventricle; RV: right ventricle; SVR: systemic vascular resistance; LVOT: left ventricular outflow tract; RA: right atrium; MR: mitral regurgitation; AR: aortic regurgitation.
* Patients with hyperdynamic, normal, or only mildly impaired LV systolic function are unlikely to have shock due to LV systolic dysfunction so other causes of hypotension should be considered.
¶ Hypovolemia typically manifests as small LV size at end-diastole. Associated with normal (or hyperdynamic) LV systolic function.
Δ Low SVR typically manifests as hyperdynamic LV systolic function, with a normal (or small) LV cavity size at end-diastole and small LV size at end-systole.
◊ Dynamic LVOT obstruction may occur with or without left ventricular hypertrophy. Acute mitral regurgitation may be induced by dynamic LVOT.
§ Multiple views may be required to identify a loculated effusion or hematoma that may cause cardiac tamponade.
¥ In the setting of pulmonary embolus, thrombus may be visualized in the right heart and/or in the pulmonary arteries.
‡ Acute inferior myocardial infarction may be complicated by RV infarction; hemodynamic compromise is generally greater than expected with inferior myocardial infarction alone.
† Causes of acute MR include ruptured chordae tendinae (due to degenerative disease, infective endocarditis, trauma, rheumatic heart disease, or spontaneous rupture), papillary muscle rupture (due to acute myocardial infarction or ischemia, or trauma), papillary muscle displacement due to myocardial infarction or ischemia, or induction of MR in the setting of dynamic LVOT obstruction (refer to footnote ◊).
** Causes of acute AR include endocarditis, aortic dissection, spontaneous or traumatic rupture of an aortic cusp, and as a complication of a procedure (such as aortic balloon valvotomy or transcatheter aortic valve implantation).
¶¶ Ascending aortic dissection may cause hypotension due to hypovolemia (aortic rupture), cardiac tamponade, acute aortic valve regurgitation, and/or acute myocardial ischemia/infarction.
ΔΔ Aortic stenosis is a chronic condition that may cause acute hypotension in response to hemodynamic alterations such as vasodilation.
◊◊ With tension pneumothorax/hemothorax, TEE may detect cardiac displacement and/or compression.
§§ With air embolism, intracardiac or intravascular bubbles may be identified (particularly in the RA and RV).
¥¥ Causes of cardiogenic shock include acute myocardial infarction (with or without mechanical complications such as free wall rupture or interventricular septal rupture), myocarditis, and various types of cardiomyopathy.