You have arrived on the scene of a paramedic who was shot as she approached a residence on a call. The scene has since been secured. Your patient is a 38-year-old female with one gunshot wound to the left side of the chest at the 5th intercostal space in the midaxillary line. She is pale, cool, and awake but agitated. She is diaphoretic and complaining of pain in her left side and difficulty breathing. The patient's EMT-B partner has applied oxygen by nonrebreathing mask and an occlusive dressing over the entry wound before your arrival. As you continue your assessment, the patient's level of consciousness decreases. She responds to verbal stimuli. Her airway is clear, her breathing rate is 38 per minute and shallow, her neck veins are flat, and her breath sounds are absent on the left side. The patient lacks a radial pulse, and her abdomen is nonguarded and nontender.