Obesity, especially morbid obesity, results in reduced lung volumes, significant atelectasis in dependent lung regions and a ventilation/perfusion mismatch. At the same time oxygen consumption and the work of breathing are increased. The reason for this lies in specific changes in the anatomy and physiology of obese patients, amplifying the risks associated with general anaesthesia compared to non-obese patients and making obese patients prone to perioperative complications4. An altered strategy to pre-oxygenation and induction for obese patients may be considered, as desaturation occurs quickly in the lung and airway management can be difficult.