When a patient requires a chest tube, also known as a thoracostomy tube, it is typically because air, fluid, or blood has collected in the pleural space between the lung and the chest wall. This accumulation prevents the lung from fully expanding, making breathing difficult for the patient. The chest tube is inserted into this space and connected to a closed drainage system. This system works to restore the normal negative pressure needed for proper lung function, allowing unwanted material to drain out while preventing atmospheric air from re-entering the chest cavity.
Defining Tidaling and Its Normalcy
The term “tidaling” describes the rhythmic fluctuation of fluid visible within the water seal chamber of the chest drainage unit. This movement appears as the fluid level rises and falls in a cyclical pattern. Observing tidaling is a positive sign because it confirms that the chest tube remains open and patent, meaning the connection between the patient’s chest and the drainage system is intact. This fluctuation directly reflects the pressure dynamics within the chest cavity being transmitted through the tube. The fluid movement should correspond with the patient’s breathing pattern, which acts as a simple visual check of the tube’s functionality.
The Physiological Reason for Tidaling
Tidaling occurs due to the natural changes in intrathoracic pressure that happen as a person breathes. When a spontaneously breathing patient takes a breath in (inspiration), the diaphragm contracts and the chest wall expands, making the pressure inside the chest more negative. This increased negative pressure pulls the fluid column in the water seal chamber upward, causing the visible rise in the fluid level. Conversely, when the patient breathes out (expiration), the chest volume decreases, and the intrathoracic pressure becomes less negative. For patients receiving mechanical ventilation, this pattern is often reversed because the ventilator forces air into the lungs with positive pressure.
What it Means When Tidaling Stops
The cessation of tidaling is a significant observation that requires careful assessment, as it can indicate one of two vastly different scenarios. In a positive outcome, the absence of tidaling suggests the patient’s lung has fully re-expanded and sealed the pleural space. When the lung is completely healed and re-expanded, the chest wall’s pressure changes are no longer transmitted through the tube to the water seal chamber. This often signals that the chest tube has served its purpose and may be ready for removal by the healthcare provider.
However, a sudden stop in tidaling can also be a warning sign that the chest tube system is obstructed. The tubing may be kinked, clamped, or blocked internally by a blood clot or thick drainage. An obstructed tube is a serious concern because it prevents the drainage unit from relieving pressure in the chest cavity. This blockage can lead to a dangerous buildup of air or fluid if the underlying condition is not resolved. If tidaling stops unexpectedly, the tubing must be immediately inspected for any kinks or dependent loops that may be impeding the flow.