This chapter addresses cardiopulmonary bypass (CPB) in thoracoabdominal aortic aneurysm (TAAA) and type B aortic dissection repairs, emphasizing open surgical repair as the gold standard. It outlines the Crawford Classification for aortic aneurysms and the DeBakey and Stanford classifications for dissections, highlighting the need for clear team communication. Various perfusion and surgical techniques are explored, ranging from traditional clamp and sew methods to advanced approaches like partial CPB and left heart bypass, each assessed for advantages and challenges. This chapter emphasizes meticulous preoperative assessments and anesthetic considerations for the complex patient demographic typical of thoracoabdominal aortic repairs. It covers organ protection strategies, including spinal cord, mesenteric, and renal protection, and discusses managing coagulopathy during surgery. Concluding with the importance of a coordinated team approach, this chapter underscores tailored CPB techniques for optimal patient-specific surgical outcomes.