Final answer:
The most common cause of hypotension in the PACU is dehydration and medications that affect fluid balance.
Step-by-step explanation:
Orthostatic hypotension refers to a decrease in blood pressure upon standing up, and it is a common condition in the Post-Anesthesia Care Unit (PACU). The most common cause of hypotension in the PACU is dehydration and medications that affect fluid balance, such as diuretics or vasodilators. These medications are commonly used in perioperative care to treat conditions like high blood pressure, and their regulation can improve postoperative hypotension. Additionally, it is important to increase fluid intake and retain water through salt intake to improve blood volume.