Final answer:
The first signs of hypotension after regional anesthesia typically include dizziness and lightheadedness, which are manifestations of orthostatic hypotension caused by a decrease in blood pressure.
Step-by-step explanation:
One of the first signs and symptoms (S/S) of hypotension after receiving regional anesthesia is likely to be dizziness and lightheadedness. This can occur due to a drop in blood pressure that is not adequately compensated by the sympathetic nervous system. In cases where the blood volume is too low or if the sympathetic reflex is not effective, a person may experience orthostatic hypotension. This refers to a decrease in blood pressure upon standing and can manifest as dizziness, lightheadedness, or even fainting. Intervention might include increasing fluid intake or adjusting medications that influence blood pressure.