ObjectTo evaluate the feasibility of measuring the descending aortic blood flow using transesophageal ultrasound Doppler under cardiopulmonary bypass (CPB). MethodWe retrospectively analyzed the clinical data of 10 adult patients accepted elective cardiac surgery under CPB in March 2014 year. There were 4 males and 6 females with a mean age of 44.5±12.3 years ranging from 24.5-64.0 years. The descending aorta diameter and velocity time integral (VTI) of blood flow of middle esophageal and lower esophageal of these patients were detected by transesophageal echocardiography (TEE) under CPB. We took the formula of classic ultrasound texting the blood flow to calculate the descending aorta blood flow (DABF). At the same time, we recorded the data of CPB and index of hemodynamics. Compared with the flow of CPB pump, we analyzed the correlation between pump flow and the raliability of DABF texting value under CPB. ResultsTwo patients quit the trail for blurred imaging. The quality of blood flow spectrum images aquirded from the middle esophageal were inferior to those from the lower esophageal (P < 0.01) in the 10 patients. Among the patients 90% of DABF from the middle esophageal and 50% of DABF from the lower esophageal were more than pump flow. however, the texting value had an excellence correlation to PF (r=0.795, r=0.825). ConclusionThe classical TEE technique can not obtain accurate blood flow during CPB.