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: Distended neck veins are more indicative of fluid overload or cardiac tamponade rather than a pneumothorax. While central line complications can affect circulation, neck vein distension is not a primary sign of collapsed lung tissue. B. Diminished breath sounds: Diminished or absent breath sounds on the affected side are a hallmark sign of pneumothorax. Air in the pleural space prevents normal lung expansion, reducing or eliminating audible breath sounds during auscultation, making this a critical finding to monitor. C. Irregular heart rate: An irregular heart rate may occur with electrolyte imbalances or cardiac conditions but is not a specific indicator of pneumothorax. While tension pneumothorax can affect cardiac output, early detection relies primarily on respiratory assessment. D. Itching over the incision: Itching at the insertion site is a minor local reaction and does not indicate pneumothorax. It may occur due to healing or mild irritation from dressings, but it does not reflect a life-threatening complication.