一位診斷為液體容積不足的病人，護理師應預期觀察到下列哪項臨床表現？
A client is diagnosed with fluid volume deficit. Which clinical manifestation should the nurse anticipate observing?
- ADistended neck veins頸靜脈擴張
- BBounding peripheral pulses周邊脈搏強勁
- COrthostatic hypotension✓ 正解姿勢性低血壓
- DIncreased urine output尿量增加
液體容積不足（Fluid Volume Deficit）導致血管內血容量減少，進而引發心輸出量下降與灌流不足。姿位性低血壓（Orthostatic hypotension）是因為身體在改變體位時，無法透過交感神經反射快速收縮血管以維持血壓，導致血壓驟降。這是診斷脫水與液體不足的敏感臨床指標。其他選項如頸靜脈怒張或強大脈搏通常與液體容積過多（Fluid Volume Excess）相關。
Fluid volume deficit results in decreased intravascular volume, which in turn leads to reduced cardiac output and inadequate perfusion. Orthostatic hypotension occurs because the body, on positional change, cannot rapidly constrict the vessels via the sympathetic reflex to maintain blood pressure, causing an abrupt drop. This is a sensitive clinical indicator for diagnosing dehydration and fluid deficit. Other options such as distended neck veins or bounding pulses are usually associated with fluid volume excess.