When assessing a chest tube with a water seal drainage system, what does tidaling indicate?

Tidaling within a water seal drainage system refers to the movement of fluid in the water chamber in response to the patient's breathing. When a patient inhales, the pressure within the pleural cavity decreases, which leads to a rise in the water level in the chamber. Conversely, during exhalation, the pressure increases, and the water level drops. This visible fluctuation is a sign that the system is functioning normally, indicating that the pleural space is communicating with the drainage system and that the lung is re-expanding effectively.

In a healthy functioning system, tidaling is expected and suggests that the chest tube is properly placed and is draining air or fluid as intended. If tidaling is absent, it could suggest a blockage in the tube or that the lung has fully expanded, although this would require further assessment to verify the underlying cause.