Either of the highlighted areas are acceptable answers. In the supine patient the air first collects anteromedially.

2. Radiographic signs of pneumothorax include all of the following except:
Interface extending beyond chest wall
Lucencies extending beyond the chest wall are more consistent with subcutaneous emphysema. Other answers are all signs of pneumothorax.

3. Subcutaneous emphysema can result from all of the following except:
Pneumoperitoneum
Pneumoperitoneum should not cause subcutaneous emphysema in the chest in a patient with an intact diaphragm.

4. What kills a patient with a tension pneumothorax?
Decreased venous return to the heart
Increased intrathoracic pressures and kinking of the SVC and IVC will all decrease venous return to the heart.

5. Which one of the following is not a common cause of pneumothorax in the ICU patient?
Chest compressions
Chest compressions during emergent resuscitation rarely results in pneumothorax.