Interstitial pulmonary emphysema (IPE) is the initial manifestation of ventilator-induced barotrauma and, if unrecognized, may eventuate in life-threatening complications. It can be diagnosed by certain radiographic criteria that reflect the pathophysiology. These include parenchymal stippling, lucent mottling and streaking, perivascular halos, subpleural cysts, lucent bands, and parenchymal cysts or bullae. In the presence of continuing airway pressure elevation and/or significant underlying lung pathology, certain complications of IPE can be anticipated. These include air leak, air block, secondary infection, and extensive pulmonary fibrosis. In the patient who is already in a state of respiratory compromise, pneumothorax or alteration in cardiovascular dynamics can constitute a terminal event. We believe, therefore, that the earliest possible recognition of the radiographic changes of IPE is critical in the management of the patient who requires ventilatory assistance.