Cerebral Perfusion Monitoring With Transpharyngeal Ultrasonography

This prospective observational pilot study investigates transpharyngeal ultrasonography (TPU) as an additional neuromonitoring strategy to assess cerebral perfusion during on-pump cardiovascular surgery. In the first part of the study the investigators will investigate the feasibility of TPU for visualization of aortic arch branches including the innominate and the carotid arteries in twenty patients undergoing coronary artery bypass grafting with extracorporeal circulation (cohort 1.). In the second part the investigators plan to adopt the investigators previous experiences on TPU to a selected population of twelve patients undergoing ascending aortic and/or arch repair in deep hypothermic circulatory arrest (DHCA, cohort 2.). In contrast to cohort 1., patients in cohort 2. are exposed intraoperatively to intermittent cerebral perfusion stops or reductions due to surgical procedure, perfusion technique and their underlying disease (aortic dissection or aortic aneurysm). The investigators hypothesize that cerebral perfusion monitoring using TPU as a non-invasive technique provides a simple and real-time adjunct to assess blood flow velocity in the extracranial cephalic vessels with Doppler ultrasound. Especially in aortic arch surgery with its inherent risk of cerebral hypoperfusion TPU might be a valuable adjunct to routine.