Anaesthesia Which of the following is true to the immediate postoperative period in a young patient with previously normal lungs having upper abdominal surgery ? A Arterial oxygen tension will typically be reduced by an average of 10 mm Hg when breathing room air B Arterial oxygen tension will normalize after 15 minutes C Diffusion hypoxia is the major determinant of arterial hypoxaemia D The CXR will typically reveal no abnormalities 💡 Explanation Which of the following is true to the immediate postoperative period in a young patient with previously normal lungs having upper abdominal surgery ? ✓ Correct Answer: A. Arterial oxygen tension will typically be reduced by an average of 10 mm Hg when breathing room air