Carbon monoxide poisoning — FRCA Primary MCQ

Correct answer: E — Hypothermia shifts the oxyhaemoglobin curve left

Carbon monoxide reduces oxygen content and shifts the remaining haemoglobin curve left. Closing capacity exceeding FRC causes airway closure is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Citrate binds ionised calcium is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Reduced baroreceptor firing increases sympathetic outflow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Chronic hypertension shifts cerebral autoregulation right 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