Figure 60-11 Infants and young children have highly compliant airway structures. With normal respiration, some dynamic collapse of the extrathoracic upper airway occurs (broken line). When a child has upper airway obstruction (as in epiglottitis, laryngotracheobronchitis, and extrathoracic foreign body) (shaded area) and struggles to breathe against this obstruction, dynamic collapse of the trachea increases. This increase in dynamic collapse (dotted line) augments mechanical obstruction of the airway. Therefore, until the airway is secured, it is important to avoid procedures that will upset the child. (Redrawn with modification from Coté CJ, Todres ID: The pediatric airway. In Coté CJ, Ryan JF, Todres ID, et al [eds]: A Practice of Anesthesia for Infants and Children, 2nd ed. Philadelphia, WB Saunders, 1992, p 55.)