Barotrauma is physical tissue damage caused by an unrelieved pressure differential between a surrounding gas or fluid and an unvented body cavity (e.g., sinuses, lungs), or across a tissue plane. The damage is due to compressive/ expansive forces and shear, leading to overstretching of tissues. Barotrauma most usually causes sinus injury or middle-ear injury, but may also cause facial injury, tooth injury, gastrointestinal (GI) rupture, pneumothorax, pulmonary hemorrhage, mediastinal and subcutaneous emphysema. Tears in pulmonary tissue can allow gas to enter the circulation. This causes embolic blockage of the circulation at distant sites or interferes with normal organ function.