injuries poisoning
Pulmonary Barotrauma
Introduction
Barotrauma is tissue injury caused by a pressure-related change in body compartment gas volume. Factors increasing risk of pulmonary barotrauma include certain behaviors (eg, rapid ascent, breath-holding, breathing compressed air) and lung disorders (eg, COPD [chronic obstructive pulmonary disease]). Pneumothorax and pneumomediastinum are common manifestations. Patients require neurologic examination and chest imaging. Pneumothorax is treated. Prevention involves decreasing risky behaviors and counseling high-risk divers. (See also Overview of Diving Injuries and Overexpansion and alveolar rupturecan occur when breath holding occurs (usually while breathing compressed air) during ascent, particularly rapid ascent. The result can be Pneumothorax (causing dyspnea, chest pain, and unilateral decrease in breath sounds) Pneumomediastinum (causing sensation of fullness in the chest, neck pain, pleuritic chest pain that may radiate to the shoulders, dyspnea, coughing, hoarseness, and dysphagia). The most common form of pulmonary barotrauma is pneumomediastinum. Mediastinal air can track into the neck, causing subcutaneous emphysema detectable as crepitation, and voice changes. A crackling sound rarely heard over the heart ("mediastinal crunch," Hamman sign). Air can sometimes track caudad into the peritoneal cavity (falsely suggesting a ruptured viscus and the need for laparotomy), but it does not typically cause peritoneal signs. Pneumothorax (Tension) , although rare with barotrauma, can cause hypotension, distended neck veins, hyperresonance to percussion, and, as a late finding, tracheal deviation. Alveolar rupture can allow air into the pulmonary venous circulation with subsequent Arterial Gas Embolism , which is particularly dangerous when it involves the brain, but can also affect other organs (eg, spinal cord, heart, skin, kidneys, spleen, gastrointestinal tract). Compression of the lungsmay occur during very deep descent in breath-hold diving; compression may rarely decrease lung volume below residual volume, causing mucosal edema, vascular engorgement, pulmonary edema, and hemorrhage, which manifest clinically as dyspnea and hemoptysis on ascent. 