Dead space is increased by all except

Dead space is actually composed of gases in nonrespiratory airways (anatomic dead space) and alveoli that are not perfused (alveolar dead space). The sum of the two components is referred to as physiological dead space. In the upright position, dead space is normally about 150 mL for most adults (approximately 2 mL/kg) and is nearly all anatomic. The weight of an individual in pounds is roughly equivalent to dead space in milliliters. Dead space can be affected by a variety of factors. Endotracheal intubation decreases the dead space. Ref: Miller&;s anesthesia 8th edition Ref: Morgan & Mikhail&;s clinical anesthesiology 6e