Capillary oedema — FRCA Primary MCQ

Correct answer: A — Reduced haemoglobin lowers arterial oxygen content

Dilution of plasma proteins and raised hydrostatic pressure favour oedema. Central chemoreceptors respond to CSF hydrogen ion concentration 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. 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. Increased preload increases stroke volume through fibre stretch 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