Final answer:
The nurse's first action should be to observe the connections of the chest drainage system to identify any issues. If the connections are intact, the healthcare provider should be notified for further assessment. Clamping the chest tube or adding water are not first-line actions without proper initial observation.
Step-by-step explanation:
In the situation described where a patient with a pneumothorax has a chest drainage device that is showing continuous bubbling in the underwater seal, the nurse needs to assess whether this is indicative of an ongoing air leak or a problem with the system. The most appropriate first action for the nurse would be to observe the connections of the drainage system. Faulty or loose connections could result in continuous bubbling and may suggest air is entering the system, compromising the negative pressure needed for lung expansion.
If no problems are found with the system's connections, then notifying the healthcare provider (HCP) would be the next appropriate step. This way, further assessment can be done to rule out potential issues such as a persistent air leak from the lung.
Clamping the chest tube at the insertion site or adding sterile water to the underwater seal chamber are not initially indicated without the proper assessment of the drainage system connections and potentially communicating with the HCP based on the collected data.