What does tidaling in the water-seal chamber indicate, and what does loss of tidaling imply?

• A. Tidaling indicates air movement with respiration; loss of tidaling may indicate lung re-expansion or an occluded tube or sealed pleural space
• B. Tidaling indicates suction failure
• C. Tidaling indicates the collection bag is full
• D. Tidaling is not related to chest tube function

Answer: (B)

Tidaling in the water-seal chamber reflects air moving between the pleural space and the atmosphere as you breathe. The water level rises and falls with respiration, indicating the system remains patent and there is communication with the pleural space. Loss of tidaling means that air movement has ceased, which can happen if the lung has re-expanded and no air is entering the pleural space, or if the chest tube or lumen is occluded or the pleural space has become sealed. It does not indicate suction failure or that the collection bag is full, and tidaling is a sign of chest tube function and its interaction with the patient's breathing.