response, preparations should be made for both needle aspiration of pleural air and placement of a chest tube, so that these procedures can be performed without delay if indicated by the patient’s clinical condition or diagnostic workup Clinical Assessment The child with suspected pneumothorax or hemothorax should undergo a thorough primary survey, looking for signs of compromised airway, breathing, or circulation Careful attention to vital signs, particularly tachycardia, tachypnea, and hypoxemia, may lead to discovery of impaired physiology not otherwise detected by physical examination It is important to recognize that due to children’s excellent vascular compensation abilities, hypotension is a late finding in pediatric shock and a normal blood pressure therefore does not rule out circulatory compromise Some patients with a pneumothorax may be asymptomatic Others may be tachypneic, complain of pleuritic chest pain, or be in severe respiratory distress Physical examination may be normal or may reveal diminished or absent breath sounds, crepitus, or hyperresonance to percussion on the side of the pneumothorax If a tension pneumothorax develops, findings may include tracheal deviation to the contralateral side and distended neck veins from impaired venous return to the heart through the deviated superior vena cava Some of these physical findings may be difficult to discern in a fully immobilized child in a noisy resuscitation room Patients with hemothorax may present in respiratory distress or profound shock secondary to obstruction of venous return or blood loss Decreased breath sounds are noted on the affected side, and there may be tracheal or mediastinal deviation Thirty percent to 40% of the patient’s blood volume may be rapidly lost in the pleural cavity with major vessel lacerations Bleeding from the intercostal or internal mammary arteries usually stops as systemic blood pressure falls and reexpansion of the lung may provide some tamponade effect Tension Pneumothorax A tension pneumothorax is the most common complicated intrapleural injury Tension pneumothorax develops in up to 20% of children after simple pneumothorax A tension pneumothorax occurs when there is progressive accumulation of air within the pleural cavity A laceration to the chest wall, pulmonary parenchyma, or tracheobronchial tree may function as a one-way valve, allowing air to enter but not leave the pleural space The progressive accumulation of air within the pleural cavity not only collapses the ipsilateral