Saunders Respiratory Practice

What conclusion should the nurse draw if there is fluctuation of the fluid level in the water-seal chamber of a closed chest tube drainage system?

1. The chest tube is blocked.

2. The chest tube is malfunctioning.

3. The chest tube is functioning as expected.

4. The chest tube needs to be replaced.

The correct answer is: The chest tube is functioning as expected.

Fluctuation of the fluid level in the water-seal chamber of a closed chest tube drainage system, commonly referred to as "tidaling," is a normal and expected phenomenon. This fluctuation occurs with each breath, reflecting changes in intrathoracic pressure as the patient inhales and exhales. When the patient breathes in, the pressure inside the thoracic cavity decreases, causing the fluid level in the water-seal chamber to rise, while during exhalation, the pressure increases, causing the fluid level to drop. This indicates that the chest tube is effectively draining air or fluid from the pleural space and that the system is functioning properly. In contrast, other outcomes such as a blocked tube would typically prevent drainage and eliminate the fluctuation, while a malfunctioning chest tube may lead to no fluctuation or a constant level of fluid, indicating something is wrong. Likewise, replacement of the tube would not be necessary if it is functioning as expected. Therefore, the observed fluctuations confirm that the chest tube is doing its job effectively, signaling that the system is operational and there is adequate airflow or fluid outflow as intended.