How do I diagnose an air leak in a chest tube (chest drainage tube)?

Diagnosing an Air Leak in a Chest Tube

The presence of air bubbling in the underwater seal collection system is the definitive sign of an air leak in a chest tube. 1

Visual Assessment of Air Leaks

• When a chest tube is connected to an underwater seal system, bubbling into the collection bottle indicates air in the pleural space (pyopneumothorax) 1
• Continuous bubbling suggests an ongoing visceral pleural air leak 1
• Continuous bubbling may also occur when the chest tube is partially dislodged with one of the tube holes open to the atmosphere, particularly in patients on suction 1
• The respiratory swing (fluctuation) of fluid in the chest tube is useful for assessing tube patency and confirms proper positioning in the pleural cavity 1

Air Leak Management Protocol

Initial Assessment

• Connect all chest tubes to a unidirectional flow drainage system (underwater seal bottle) which must be kept below the level of the patient's chest at all times 1
• The underwater seal should have the tube placed under water at a depth of approximately 1-2 cm 1
• Observe for bubbling in the collection system, which indicates air in the pleural space 1

Safety Considerations

• A bubbling chest tube should never be clamped as this may lead to the potentially fatal complication of tension pneumothorax 1
• If a chest tube is clamped for any reason (such as during fibrinolytic therapy), it should be immediately unclamped if the patient complains of breathlessness or chest pain 1
• Patients with chest tubes should be managed on specialized wards by staff trained in chest tube management 1

Distinguishing Types of Air Leaks

• Continuous bubbling: Suggests an ongoing visceral pleural air leak or bronchopleural fistula 1
• Intermittent bubbling: May indicate a smaller air leak that occurs only during certain phases of respiration 1
• No bubbling but failure of lung expansion: May indicate tube obstruction, kinking, or improper positioning 1

Assessing for Persistent Air Leaks

• An air leak persisting beyond 4 days is considered a persistent air leak 1
• For patients with persistent air leaks, continued observation for 4 days is recommended for spontaneous closure of bronchopleural fistula 1
• If air leaks persist beyond 4 days, surgical evaluation should be considered 1
• In primary spontaneous pneumothorax, 75% of air leaks cease by 7 days and 100% by 15 days 2
• In secondary spontaneous pneumothorax, 61% of air leaks resolve by 7 days and 79% by 14 days 2

Troubleshooting Chest Tube Issues

• When there is a sudden cessation of fluid draining, check for obstruction (blockage or kinking) by flushing with normal saline 1
• Small soft drains are prone to kinking, especially in mobile patients, which should be checked first 1
• Obstruction may be due to thick secretions blocking the lumen, requiring careful flushing with normal saline (10 ml is usually adequate for a small bore drain) 1

Modern Approaches to Air Leak Detection

• Digital air leak monitoring systems can provide continuous, objective measurement of air leak flow 3
• These systems can help identify air leak resolution more accurately than visual assessment, potentially reducing chest tube duration and hospital stay 3
• Digital monitoring has been shown to reduce chest tube duration by approximately 0.9 days compared to traditional visual assessment protocols 3

Remember that proper management of chest tubes and accurate diagnosis of air leaks are essential for patient safety and optimal outcomes in the treatment of pneumothorax and other pleural conditions.