What is the purpose of connecting a chest tube to water seal (underwater drainage system)?

From the Guidelines

A chest tube to water seal is a crucial step in the management of pneumothorax, allowing for the removal of air or fluid from the pleural space while maintaining negative pressure for proper lung expansion. This system typically consists of three chambers: a collection chamber for drainage, a water seal chamber that prevents air backflow, and sometimes a suction control chamber. When a patient is placed "to water seal," it means the chest tube remains connected to the drainage system but active suction is discontinued, allowing the system to function passively 1.

Key Considerations

• The water seal creates a barrier that maintains negative pressure in the pleural space, which is essential for proper lung expansion.
• The system allows for the monitoring of drainage amount, color, and air leak presence to determine if the chest tube can be safely removed.
• According to the BTS guidelines, simple aspiration is recommended as first-line treatment for primary pneumothoraces, but chest tube drainage may be necessary for larger or secondary pneumothoraces 1.
• The American College of Chest Physicians recommends using a small-bore catheter or a 16F to 22F chest tube attached to a water seal device or a Heimlich valve for lung reexpansion 1.

Clinical Application

• Healthcare providers should monitor patients on water seal closely to determine if the chest tube can be safely removed.
• The decision to place a patient on water seal should be based on individual patient needs and clinical judgment.
• The use of water seal systems can help reduce the risk of complications and improve patient outcomes in the management of pneumothorax 1.

From the Research

Definition of Chest Tube to Water Seal

• A chest tube to water seal refers to the practice of connecting a chest tube to a water seal drainage system, which allows air and fluid to escape from the chest cavity while preventing air from entering 2.
• This setup is often used to manage air leaks and pneumothorax after pulmonary surgery 3.

Benefits of Chest Tube to Water Seal

• Placing chest tubes on water seal has been shown to be superior to suction for stopping air leaks after pulmonary resection 3.
• Water seal can shorten the duration of air leaks and decrease the time that chest tubes remain in place 4.
• The use of water seal can also reduce the risk of pneumothorax and subcutaneous emphysema 2.

Comparison to Suction

• Studies have compared the effectiveness of water seal to suction in managing chest tubes after pulmonary surgery 3, 4, 5.
• The results suggest that water seal is superior to suction in stopping air leaks and reducing the duration of chest tube placement 3, 4.
• However, a meta-analysis found that suction resulted in a longer chest tube duration and a smaller postoperative pneumothorax compared to water seal 6.

Clinical Applications

• Chest tube to water seal is commonly used in patients undergoing pulmonary surgery, such as lobectomy or wedge resection 2, 3, 4.
• The decision to use water seal or suction should be based on individual patient factors, such as the size of the air leak and the presence of pneumothorax 2, 3.