一位頭部外傷病人的顱內壓（ICP）為 18 mmHg，平均動脈壓（MAP）為 70 mmHg。護理師對此結果的最佳解釋為何？
A client with a head injury has an intracranial pressure (ICP) of 18 mmHg and a mean arterial pressure (MAP) of 70 mmHg. Which is the best interpretation of these findings?
- AThe client is at risk for cerebral ischemia✓ 正解病人有腦缺血的風險
- BThe intracranial pressure is critically low顱內壓顯著偏低
- CThe cerebral perfusion pressure is within normal limits腦灌注壓在正常範圍內
- DThe findings are expected for a client with a head injury這些發現符合頭部外傷病人的預期狀況
這題需要計算腦灌注壓（CPP）並評估其臨床意義。CPP = MAP - ICP。在此案例中，CPP = 70 - 18 = 52 mmHg。正常 CPP 的範圍是 60 至 100 mmHg。當 CPP 低於 60 mmHg 時，大腦血流量會顯著減少，導致腦缺血（Cerebral Ischemia）和進一步的腦損傷。雖然 ICP 18 mmHg 僅輕微高於正常上限（10-15 mmHg），但因為病人的 MAP 較低（70 mmHg），導致計算出來的灌注壓不足。護理師必須理解，單看 ICP 或 MAP 都不夠全面，必須結合兩者評估腦部的血液供應風險。因此，解釋為缺血風險（A）是最精確的。這屬於 Reduction of Risk Potential 中監測與解釋複雜診斷數據的能力。
This question requires calculation of cerebral perfusion pressure (CPP) and assessment of its clinical significance. CPP = MAP - ICP. In this case, CPP = 70 - 18 = 52 mmHg. The normal range for CPP is 60 to 100 mmHg. When CPP falls below 60 mmHg, cerebral blood flow decreases significantly, leading to cerebral ischemia and further brain injury. Although the ICP of 18 mmHg is only mildly above the normal upper limit (10-15 mmHg), because the patient's MAP is low (70 mmHg), the resulting perfusion pressure is inadequate. The nurse must understand that evaluating ICP or MAP in isolation is not sufficient; both must be combined to assess the risk to cerebral blood supply. Therefore, interpreting the findings as risk for ischemia (A) is the most accurate option. This falls under the Reduction of Risk Potential domain, requiring the ability to monitor and interpret complex diagnostic data.
美國 NCLEX 非常強調 CPP = MAP - ICP 的公式計算與臨床應用；台灣護理養成中雖有提及，但在臨床上護理師較少獨立計算 CPP 並據此調整照護，通常由醫師在 ICU 設置目標值。