An adult-sized, self-inflating resuscitation bag may be carefully used on an infant, provided only the force needed to cause appropriate chest expansion is used. 3 In general, two types of manual resuscitation bags are used: the self-inflating bag and the flow-dependent bag. Self-inflating bags do not require a gas source to provide ventilation, but flow-dependent bags do require a gas flow. 7 Resuscitation bag sizes, along with other supplemental oxygen devices and oxygen administration, are summarized in Table 40-2 . Leaf-flap outlet valves should be avoided when a self-inflating bag is used to assist spontaneous ventilation in an infant because the infant cannot generate enough negative inspiratory pressure to open the valve. 3 Resuscitation bags equipped with spring-loaded, positive end-expiratory pressure (PEEP) valves to provide continuous positive airway pressure (CPAP) must not be used with the spontaneously breathing child for the same reason previously discussed. 3 Flow-inflating bags have no flow valves that require opening on inspiration and, therefore, may be used to provide supplemental oxygen, PEEP, or CPAP to the spontaneously breathing infant or child. 3 Pressure manometers may be attached to these bags to measure peak inspiratory pressure. Ventilatory masks are measured in the child, as in the adult, from the bridge of the nose to the point before the end of the chin. Using a correctly sized mask for the infant or child is critical for adequate oxygenation and ventilation of the patient.