Fetal haemoglobin — FRCA Primary MCQ

Correct answer: C — Hypothermia shifts the oxyhaemoglobin curve left

Fetal haemoglobin has higher oxygen affinity than adult haemoglobin. Reduced baroreceptor firing increases sympathetic outflow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Increased preload increases stroke volume through fibre stretch is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Aldosterone increases sodium reabsorption and potassium secretion 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