Preventing Oxygen Desaturation in Morbidly Obese Patients during ECT

Abstract

Preoxygenation is conventionally performed using a face mask with oxygen in a supine position, and oxygenation is maintained with bag-mask ventilation during electroconvulsive therapy（ECT）. However, hypoxic episodes during ECT are not uncommon with this method, especially in morbidly obese patients. The most important property of ventilatory mechanics in patients with obesity is reduced functional residual capacity（FRC）. Thus, increasing FRC and oxygen reserves is an important step to improve oxygenation and prevent oxygen desaturation in these individuals. Head-up position and use of apneic oxygenation such as low-flow nasal oxygen or high-flow nasal oxygen help increase FRC and oxygen reserves, resulting in improved oxygenation and prolonged safe apnea period. Furthermore, difficult mask ventilation is more frequent in morbidly obese individuals. Supraglottic airway devices（SGAs）are useful in establishing effective ventilation in patients with difficult airways. Therefore the use of SGAs is strongly recommended in these patients.