Fibrosis compliance — FRCA Primary MCQ

Correct answer: E — Closing capacity exceeding FRC causes airway closure

Fibrosis reduces static lung compliance. Hypocapnia causes cerebral vasoconstriction is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Reduced haemoglobin lowers arterial oxygen content 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. 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. 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