For cases of hypotension occurring in pheochromocytoma, it is most commonly seen after the surgical removal of the tumor. At this point, the concentration of catecholamines in the blood may significantly decrease, leading to a marked reduction in effective circulating blood volume, and thus causing hypotension. This situation is relatively common after surgery for pheochromocytoma. Usually, after surgical treatment and removal of the tumor, it is important to promptly discontinue the use of receptor blockers in patients and to appropriately replenish blood volume to effectively maintain central venous pressure. This approach can generally counteract the reduction in catecholamine levels caused by surgery, which leads to hypotension.