Comment:

The pre‑bronchodilator FEVI is normal. The forced vital capacity is at the lower limit of normal. The spirometric ratio is raised. Gas transfer is normal. Static lung volumes are generally mildly reduced. The ERV is severely reduced, consistent with the patient's BMI of 58. Arterial blood gases on room air show mild hypoxaemia, normal carbon dioxide and adequate saturation. The A‑a gradient is mildly elevated. Overall, the results are consistent with extraparenchymal restriction related to the patient's obesity.