Figure 66-10 Ultrasound image of the Remote Access Perfusion (Estech Systems, Inc., Plano, TX) catheter balloon in situ. Transesophageal echocardiography allows the anesthesiologist to keep track of migration of the catheter balloon. The balloon should be positioned in the ascending aorta 2 to 4 cm distal to the aortic valve. Right radial pressure catheter dampening can detect balloon malposition when occlusion of the innominate artery occurs.