— 生理適應 · MEDIUM · MCQ —
一位嚴重燒傷病人有低血容量性休克的風險。何項為此情況的最早期跡象？
A client with severe burns is at risk for hypovolemic shock. Which is the earliest sign of this condition?
- ADecreased blood pressure血壓下降
- BCool, clammy skin皮膚濕冷
- CDecreased urine output尿量減少
- DIncreased heart rate✓ 正解心率增加
— Explanation · 中文詳解 —
低血容量性休克（hypovolemic shock）發生時，身體會啟動交感神經系統以維持重要器官灌流。心跳過速（tachycardia）是為了補償因血容量減少而下降的每搏輸出量（stroke volume），以維持心輸出量（cardiac output）。這是最敏感且最早期的代償機制。血壓下降是晚期徵兆，代表代償機制已衰竭；尿量減少與皮膚變化則是後續組織灌流不足的結果。
Increased heart rate is the earliest sign of hypovolemic shock because it is a primary compensatory mechanism activated by the sympathetic nervous system to maintain cardiac output when stroke volume decreases. Blood pressure typically remains normal until late stages when compensatory mechanisms fail. Other signs like decreased urine output and cool, clammy skin occur as tissue perfusion deteriorates.