Chest Tube Basics

The pleural space is a thin potential space between the visceral pleura covering the lung and the parietal pleura lining the chest wall. Normally, its negative pressure keeps the lung expanded against the chest wall. Air entering that space abolishes the pressure gradient and can produce a pneumothorax with partial or complete lung collapse. Fluid occupies space, compresses the lung, and impairs ventilation and gas exchange; the fluid may be serous, blood, or infected material. A chest tube creates a controlled route for air or fluid to leave. Its drainage system must prevent room air from travelling back into the pleural space. The underwater seal serves this one-way function: air can bubble out through the water, but the water column resists air returning toward the patient. Re-expansion is therefore not simply a matter of “emptying the tube”; it depends on a patent tube, an intact closed system, and resolution of the process that caused the air or fluid to accumulate. The underlying problem changes what the nurse expects. A patient with a pneumothorax may have sudden pleuritic pain, dyspnoea, reduced...