Four days ago, a chest tube was inserted into the second intercostal space (ICS) of a client with a pneumothorax. Today the nurse notes that there is no fluctuation in the water seal chamber of the chest tube drainage system. Which intervention should the nurse implement next?

Rationale: A. Position the client for comfort on the nonoperative side: Repositioning may improve comfort but does not address the possible cause of absent fluctuation in the water seal chamber. This intervention would not determine whether the lung has re-expanded or if there is an obstruction in the system. B. Clamp the tubing and have the client take deep breaths: Clamping the chest tube is contraindicated unless specifically ordered, as it can cause tension pneumothorax by trapping air in the pleural space. Deep breathing will not identify the cause of the lack of fluctuation safely. C. Increase the amount of suction on the wall suction: Increasing suction arbitrarily may not correct the problem and could damage lung tissue. The absence of fluctuation may be due to re-expansion of the lung or blockage in the tubing, not inadequate suction strength. D. Assess the client’s breath sounds on the affected lung: Assessing breath sounds helps determine whether the lung has fully re-expanded or if the chest tube is obstructed. If breath sounds are equal bilaterally and the client shows no respiratory distress, the lack of fluctuation likely indicates lung re-expansion, a positive outcome.