Final answer:
The nurse should first check the chest tube connections as constant bubbling in the water seal chamber and dyspnea suggest an air leak which could be a serious complication post lobectomy.
Step-by-step explanation:
The nurse should first check the chest tube connections if the patient is 3 hours postoperative following a right upper lobectomy, with increased bloody drainage in the closed pleural drainage system, and experiencing a constant bubbling in the water seal chamber along with dyspnea. Sudden changes in the bubbling pattern from intermittent to constant may indicate the presence of an air leak in the pleural space, which could mean disconnection or a new pneumothorax. Ensuring the integrity of the chest tube system is crucial to prevent further complications, such as lung collapse due to loss of negative pressure within the chest cavity necessary for proper lung inflation.