Acute pain stress response — FRCA Primary MCQ

Correct answer: B — Reduced baroreceptor firing increases sympathetic outflow

Severe pain activates sympathetic and endocrine stress responses. Closing capacity exceeding FRC causes airway closure is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. The loop of Henle creates the medullary osmotic gradient is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Pain and temperature ascend in the spinothalamic tract is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Right ventricular afterload rises with pulmonary vascular resistance is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physiology, the correct answer is usually the variable that best explains the observed change in the anaesthetised patient.

Reference: West's Respiratory Physiology; Ganong Review of Medical Physiology; Primary FRCA textbooks