As the subclavian vein lies in close proximity to the lung, during insertion the catheter may inadvertently be threaded through both the visceral and parietal pleura and into the lung, resulting in a pneumothorax. In this case, the patient may display signs or complain of: shortness of breath, decreased breath sounds on affected side, tracheal deviation away from affected side, tachycardia, and hypotension. Alternatively, the patient may appear unaffected, which is why a chest x-ray is always required post-insertion of a PICC line. In the case of a pneumothorax, administer oxygen and insert a chest tube as indicated.