Abstract: An indicator device for verifying the correct placement of an endotracheal tube within an intubated patient's airway and for detecting the presence of a collapsed lung in an intubated patient. The device has an open proximal end and open distal end and an air conducting lumen therebetween. The distal end is attached to the non-invasive end of an endotracheal tube. The proximal end is attached to a ventilating apparatus or "ambubug." A vibrating element mounted within the device produces an audible vibration either actively in response to an electrical driver, or passively in response to air flowing through the device. As the ambubag is squeezed, air is forced through the air conducting lumen and into the intubated patient's airway. An audible sound produced by the vibrating element is mechanically coupled into the air conducting lumen and conducted through the patient's airway.