A nurse is assessing a client following the insertion of a central venous catheter. Which of the following findings indicates a pneumothorax?

A. Distended neck veins are more indicative of fluid overload or a tension pneumothorax in severe cases, but they are not the primary early sign of a simple pneumothorax following central line insertion. B. A pneumothorax occurs when air enters the pleural space, causing lung collapse. One of the hallmark signs is diminished or absent breath sounds on the affected side, often accompanied by shortness of breath and sometimes chest pain. This is a direct indicator that the lung is not fully expanding. C. An irregular heart rate is not a primary sign of pneumothorax. While tension pneumothorax may eventually cause cardiovascular compromise, an irregular heart rate alone is nonspecific and may result from other conditions. D. Itching over the catheter site is a minor local reaction and is not indicative of a pneumothorax. It may be due to healing or local irritation.