Preoxygenation Is More Effective in the 25° Head-up Position Than in the Supine Position in Severely Obese Patients

Preoxygenation in the 25 degrees head-up position achieves 23% higher oxygen tensions, allowing a clinically significant increase in the desaturation safety period--greater time for intubation and airway control. Induction in the 25 degrees head-up position may provide a greater safety margin for airway control.