We present a case report demonstrating the efficacy of carotid artery ultrasonography (CAU) and transesophageal echocardiography (TEE) to evaluate brain blood flow in a patient with acute aortic dissection that occurred during cardiopulmonary bypass (CPB).
A 75-year-old woman was scheduled for mitral valve plasty, tricuspid valve plasty, and maze operation for mitral valve regurgitation. We started CPB using an arterial cannula and aortic cross-clamp placed in the ascending aorta. We then performed the surgery and released the aortic cross-clamp.
Instantly, the left radial arterial pressure reduced and an aortic dissection began developing.
Despite rebuilding after CPB, blood flow in the bilateral common carotid arteries was observed only in the false lumen by CAU and TEE. Adding an arterial cannula to the right axillary artery, we induced adequate blood flow in the true lumen. We then performed an ascending aortic replacement. When we stopped the right axillary arterial inflow after finishing the replacement, we detected using CAU that the blood flow of the right common carotid artery was reduced. We added a bypass to the right subclavian artery from the replaced graft to get adequate blood flow.
There are several methods to evaluate brain blood flow, such as orbital ultrasound, CAU, near-infrared spectroscopy, blood pressure in superficial temporal artery, and TEE during surgery. It is important to understand the advantages and disadvantages of each method. It is also vital for anesthesiologists to confirm the monitoring systems for brain blood flow in surgery by using them properly and quickly, in the case of complications during CPB, such as aortic dissection, occur.
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