Pleural Drainage System: Key Concepts for Respiratory Care

A pleural drainage system is a medical device used with a chest tube to remove air, fluid, blood, pus, chyle, or other drainage from the pleural space. Its main purpose is to help restore normal lung expansion by removing material that should not be present between the visceral and parietal pleura.

In respiratory care, pleural drainage systems are commonly associated with pneumothorax, hemothorax, pleural effusion, empyema, chylothorax, trauma, thoracic surgery, and complications of mechanical ventilation.

Understanding how these systems work is essential because a malfunction can quickly become a serious patient safety problem.

What Is a Pleural Drainage System?

A pleural drainage system is a closed drainage device that connects to a chest tube. The chest tube is inserted into the pleural space, while the drainage system remains outside the body, usually positioned below the level of the patient’s chest.

The system is designed to perform several important functions:

• Remove air or fluid from the pleural space
• Prevent air or fluid from flowing back into the chest
• Collect and measure drainage
• Control the amount of suction applied
• Help clinicians identify air leaks
• Provide clues about chest tube patency

The pleural drainage system is both a therapeutic device and a monitoring tool. It treats the underlying problem by removing abnormal air or fluid, but it also gives clinicians important information about what is happening inside the pleural space.

Why Pleural Drainage Is Needed

The pleural space is normally a potential space between the visceral pleura, which covers the lungs, and the parietal pleura, which lines the chest wall. Under normal conditions, this space contains only a small amount of lubricating fluid. This allows the lungs to move smoothly during breathing while maintaining close contact with the chest wall.

When air or fluid enters this space, lung expansion can become impaired.

If air enters the pleural space, the condition is called a pneumothorax. Air separates the lung from the chest wall and may cause partial or complete lung collapse. If the pressure continues to build, a tension pneumothorax can develop, which can compress the lung, shift mediastinal structures, reduce venous return, and become life-threatening.

If fluid accumulates in the pleural space, it may be called a pleural effusion, hemothorax, empyema, or chylothorax, depending on the type of fluid present. A pleural effusion usually refers to abnormal fluid accumulation. A hemothorax involves blood. An empyema involves pus. A chylothorax involves lymphatic fluid called chyle.

Note: In any of these conditions, the abnormal air or fluid can interfere with ventilation, oxygenation, and lung expansion. A chest tube connected to a pleural drainage system allows the unwanted material to leave the pleural space so the lung can re-expand.

Common Indications for Chest Tube Drainage

Chest tube drainage may be needed for several conditions involving the pleural space. Common indications include pneumothorax, tension pneumothorax, hemothorax, pleural effusion, empyema, and chylothorax.

• A pneumothorax occurs when air collects in the pleural space. A small pneumothorax may resolve with observation, oxygen therapy, or needle aspiration, depending on the situation. However, a larger pneumothorax often requires chest tube insertion. A pneumothorax greater than 10% to 20% is commonly treated with a chest tube, especially if the patient is symptomatic or receiving positive-pressure ventilation.
• A tension pneumothorax is a medical emergency. It occurs when air enters the pleural space and cannot escape. Pressure rises inside the chest, causing lung compression and possible mediastinal shift. Signs may include sudden respiratory distress, hypoxemia, absent or decreased breath sounds on the affected side, hyperresonance to percussion, hypotension, tachycardia, tracheal shift, and increased peak airway pressures in mechanically ventilated patients. Emergency needle decompression may be performed first, but chest tube insertion is usually needed for ongoing management.
• A hemothorax occurs when blood collects in the pleural space. This may happen after trauma, surgery, vascular injury, or other conditions. Because blood and clots may not drain well through a small catheter, larger chest tubes are often used.
• An empyema occurs when pus collects in the pleural space, usually due to infection. Drainage may be needed to remove infected material and help the lung re-expand.
• A chylothorax occurs when chyle accumulates in the pleural space due to disruption or obstruction of the thoracic duct or lymphatic system. The drainage often appears milky or white.

Note: Pleural drainage systems may also be used after thoracic surgery or in certain cases involving mediastinal or pericardial drainage, although the main focus in respiratory care is usually the pleural space.

Chest Tube Placement Principles

Chest tube placement depends on whether air or fluid needs to be removed.

When the goal is to remove air, the chest tube is usually directed toward the apex of the lung because air rises. For a pneumothorax, the tube may be inserted using a midclavicular approach in the upper anterior chest or a midaxillary approach in the lateral chest. The exact location depends on the patient’s condition, provider preference, and institutional practice.

When the goal is to remove fluid, the chest tube is directed toward the posterior base of the lung because fluid collects in dependent areas. Fluid drainage often requires a lower placement than air drainage.

The tube is inserted over the top edge of the rib to reduce the risk of injury to the neurovascular bundle, which runs along the lower border of each rib. After insertion, the tube is secured with sutures and covered with an occlusive dressing. The distal end of the chest tube is then connected to the drainage system.

Note: A chest radiograph is commonly obtained before or after placement to evaluate the location of air or fluid, confirm tube position, and assess lung re-expansion.

Main Components of a Pleural Drainage System

Modern commercial pleural drainage systems are based on the older three-bottle system. Although most hospitals now use compact disposable units, the basic principles remain the same.

A standard system includes three main chambers:

• Collection chamber
• Water-seal chamber
• Suction-control chamber

Note: Some systems may include a fourth chamber or pressure-relief valve for added safety.

Collection Chamber

The collection chamber receives drainage from the chest tube. This may include air, blood, pus, chyle, serous fluid, or other pleural material.

This chamber allows clinicians to measure the amount of drainage over time. Drainage should be monitored and recorded according to facility policy. In many cases, output is measured hourly at first, then less frequently as the patient stabilizes.

The amount and character of the drainage are important. A sudden increase in drainage, especially bloody drainage, should be reported. The appearance of the fluid may provide clues about the underlying condition.

Red drainage suggests blood. Straw-yellow drainage may be associated with pleural effusion. Yellow or green drainage may suggest pus from empyema. White or milky drainage may suggest chyle.

The drainage system should remain upright and should not be tipped over. Tipping can cause fluid to move into the wrong chamber, interfere with accurate measurement, or affect system function. Marks may be made on the collection chamber to track drainage over time.

Note: When the collection chamber becomes full, the drainage unit must be replaced. During replacement, the chest tube may be temporarily clamped only long enough to safely change the system, then unclamped once the new unit is functioning.

Water-Seal Chamber

The water-seal chamber is one of the most important parts of the pleural drainage system. It acts as a one-way valve.

Air can leave the patient’s pleural space, pass through the drainage tubing, and bubble through the water seal. However, outside air cannot move backward into the patient’s chest because the water seal blocks reverse flow.

In many wet systems, the water-seal chamber is filled to approximately 2 cm with sterile water, although clinicians should always follow the manufacturer’s instructions for the specific unit being used.

Note: The water seal protects the patient from atmospheric air entering the pleural space. Without this one-way valve, air could be drawn into the chest and worsen or recreate a pneumothorax.

Suction-Control Chamber

The suction-control chamber regulates how much negative pressure is applied to the pleural space. In many wet suction systems, the chamber is filled with sterile water to the ordered level, commonly around −20 cm H₂O.

A key concept is that the suction-control chamber determines the suction applied to the patient, not simply the wall suction setting. The wall suction may be turned higher than the intended pleural suction level, but the water column limits and regulates the pressure transmitted to the patient.

For example, if the suction-control chamber is filled to 20 cm, the system is designed to apply approximately −20 cm H₂O of suction. The wall suction is increased only until gentle bubbling appears in the suction-control chamber. Excessive bubbling should be avoided because it can cause water evaporation and may create unnecessary noise without improving patient care.

Note: As water evaporates, the level in the suction-control chamber can fall. If the water level changes, the suction level may also change. For this reason, water levels should be checked regularly and refilled as needed.

Wet vs. Dry Pleural Drainage Systems

Traditional systems use water to create the water seal and control suction. These are often called wet systems. In a wet suction system, gentle bubbling in the suction-control chamber usually indicates that suction is being applied.

Some modern systems use dry suction control. These systems may use a dial or regulator rather than a water column to set suction. They may still have a water seal or may use a one-way mechanical valve, depending on the design.

Note: Because commercial units vary, clinicians must understand the specific system used in their facility. The basic principles are similar, but setup, markings, indicators, and troubleshooting steps may differ.

Basic Setup of a Wet Pleural Drainage System

A traditional wet three-chamber system is prepared using sterile technique. The system is opened aseptically, and the drainage unit is placed below the level of the patient’s chest.

The water-seal chamber is filled first, usually to the 2 cm mark. The suction-control chamber is then filled to the ordered suction level, commonly 20 cm H₂O. The drainage tubing is connected to the chest tube, and the suction tubing is connected to wall suction.

Wall suction is increased slowly until gentle bubbling appears in the suction-control chamber. The tubing should be checked to make sure there are no kinks, dependent loops, loose connections, or obstructions.

The water seal should be observed for tidaling, and the collection chamber should be checked for drainage. The patient should also be assessed for respiratory status, breath sounds, oxygenation, chest movement, pain, and signs of distress.

Bubbling in the Drainage System

Bubbling is an important observation because it can indicate either normal function or a problem, depending on where it occurs.

Gentle bubbling in the suction-control chamber of a wet system usually means suction is working. No bubbling in the suction-control chamber may mean that suction is not turned on, the tubing is kinked, the tubing is disconnected, the suction source is inadequate, or the vent is blocked.

Bubbling in the water-seal chamber has a different meaning. In a patient with a pneumothorax, intermittent bubbling in the water seal may indicate that air is leaving the pleural space. This may occur during expiration, coughing, or positive-pressure breaths.

Note: Continuous bubbling in the water-seal chamber usually suggests an air leak. The leak may be from the patient, the insertion site, the tubing, or the drainage system.

Air Leak Troubleshooting

If continuous bubbling is seen in the water-seal chamber, the system should be assessed for an air leak.

One method is to briefly pinch the chest tube near the insertion site. If bubbling stops, the leak is likely at the patient, the insertion site, or within the chest. If bubbling continues, the leak is likely somewhere between the patient and the drainage unit.

If the leak appears to be at the insertion site, the dressing should be assessed. A loose dressing or outward tube migration may allow air to enter. The provider should be notified. A sterile petroleum gauze dressing may be used temporarily if ordered or appropriate by facility protocol.

If the leak appears to be in the tubing or system, connections should be tightened, temporary holes or tears may be taped, and a new drainage system should be prepared if needed.

The insertion distance of the chest tube should be checked and documented. If the tube migrates outward and the most proximal drainage hole exits the skin, air may enter through the tube and mimic a persistent lung leak.

Tidaling in the Water-Seal Chamber

Tidaling refers to the rise and fall of the water level in the water-seal chamber with breathing. This movement reflects pressure changes in the pleural space.

In a spontaneously breathing patient, the water level typically rises during inspiration and falls during expiration. In a patient receiving positive-pressure ventilation, the pattern may reverse because airway pressure increases during inspiration.

Tidaling usually indicates that the chest tube is patent and communicating with the pleural space. If tidaling stops, the cause should be investigated. It may mean the lung has re-expanded, but it may also mean the tube is kinked, clamped, blocked by clot, or obstructed by fluid.

If there is no tidaling and the patient shows signs of distress, the situation should be treated as potentially serious. An obstructed chest tube can prevent air from escaping, increasing the risk of worsening pneumothorax or tension pneumothorax.

Drainage Monitoring

Drainage should be assessed for amount, color, consistency, and trend. This information should be recorded in the medical chart.

The amount of drainage helps clinicians determine whether the underlying condition is improving. Chest tubes are often considered for removal when drainage decreases significantly, although the exact threshold depends on the patient and clinical situation. Some references describe removal when pleural fluid drainage is less than about 50 mL in 24 hours, but this decision must be individualized and ordered by the provider.

The character of the drainage is also important. Bright red drainage may indicate active bleeding. Thick yellow or green drainage may indicate infection. Milky drainage may indicate chylothorax. Sudden increases in drainage should be reported.

Note: The collection chamber should be marked at regular intervals to track output accurately. The system should remain upright to prevent mixing between chambers.

Chest Tube Maintenance

Chest tube maintenance is essential for patient safety. The system should be checked frequently for migration, kinking, loose connections, dependent loops, bubbling patterns, drainage amount, drainage appearance, and water levels.

Kinking is especially concerning because it can block air or fluid from escaping the chest. In a patient with an active air leak, a kinked or clamped tube can allow pressure to build in the pleural space, potentially causing a tension pneumothorax.

Dependent loops should also be avoided. Fluid can collect in loops of tubing and impair drainage. Tubing should be positioned to allow drainage to flow smoothly into the collection chamber.

The chest tube insertion site should be assessed for drainage, air leaks, dressing integrity, and subcutaneous emphysema. Subcutaneous emphysema may feel like crackling under the skin and can indicate air leakage into the tissues.

Clamping, Stripping, and Milking

Routine clamping of chest tubes is generally discouraged. Clamping may be temporarily needed when changing the drainage system, but it should not be done unnecessarily. If air continues to leak from the lung while the tube is clamped, pressure can build in the pleural space and cause a tension pneumothorax.

Chest tubes should not be clamped during transport unless specifically ordered or required by institutional policy for a very specific reason. During transport, the drainage system should remain below the level of the patient’s chest.

Stripping and aggressive milking are also discouraged because they can create excessive negative pressure inside the tube. This may be harmful to tissue. If clots are present, gentle techniques may be used according to policy to move drainage toward the collection chamber, but rapid stripping should be avoided.

Emergency Disconnection or System Breakage

If the drainage system becomes disconnected or breaks, the response depends on the patient’s condition and whether an air leak is present.

If the patient has a leaking pneumothorax, the tube should initially remain open so air can escape. As quickly as possible, the distal end of the tubing can be placed into sterile water to create a temporary water seal. A new drainage system should be connected as soon as possible.

If the patient does not have a leaking pneumothorax, the distal end of the tube may be clamped temporarily to prevent air from entering the pleural space while a new system is prepared. The patient should be monitored closely, and the chest tube should be connected to a functioning drainage system as soon as possible.

Pleural Drainage and Mechanical Ventilation

Pleural drainage systems are especially important in patients receiving mechanical ventilation. Positive-pressure ventilation can worsen an existing air leak or contribute to barotrauma if excessive airway pressures or volumes are used.

A pneumothorax in a mechanically ventilated patient can cause sudden deterioration. Signs may include rising peak airway pressure, falling oxygen saturation, hypotension, decreased breath sounds on one side, hyperresonance, and reduced chest movement on the affected side.

In volume-controlled ventilation, an air leak through a chest tube may sometimes be estimated by comparing the delivered tidal volume with the exhaled tidal volume. If the exhaled volume is much lower than the delivered volume, air may be escaping through the pleural space and drainage system. In pressure-controlled ventilation, this calculation is less reliable, so clinicians often rely on qualitative observations such as bubbling in the water-seal chamber.

When bubbling stops in a patient who previously had an air leak, it may suggest that the pleural tear has healed. However, it can also suggest obstruction, so the entire clinical picture must be considered.

Signs of Tension Pneumothorax

A tension pneumothorax is one of the most urgent complications related to pleural air accumulation. It may occur if air enters the pleural space and cannot escape, or if a chest tube becomes blocked while an air leak continues.

Important signs include sudden respiratory distress, hypoxemia, tachycardia, hypotension, decreased or absent breath sounds on the affected side, hyperresonance to percussion, tracheal deviation away from the affected side in severe cases, and worsening ventilator pressures.

Note: Treatment requires rapid decompression. Needle decompression may be performed immediately in an emergency, followed by chest tube insertion connected to a pleural drainage system.

Patient Assessment

The drainage system should never be assessed in isolation. The patient’s clinical condition is the priority.

The respiratory therapist should monitor breath sounds, chest expansion, respiratory rate, oxygen saturation, work of breathing, heart rate, blood pressure, pain, mental status, and ventilator parameters when applicable.

The insertion site should be inspected for bleeding, drainage, dressing integrity, tube migration, and subcutaneous emphysema. The drainage system should be checked for proper water levels, bubbling, tidaling, suction function, and drainage output.

Note: If the patient becomes suddenly short of breath, hypotensive, cyanotic, anxious, or unstable, the respiratory therapist should immediately assess the chest tube system and notify the appropriate provider.

Key Takeaways

• A pleural drainage system removes air or fluid from the pleural space through a chest tube.
• The three main chambers are the collection chamber, water-seal chamber, and suction-control chamber.
• The collection chamber measures drainage.
• The water-seal chamber acts as a one-way valve.
• The suction-control chamber regulates the amount of suction applied.
• A wet water seal is commonly filled to about 2 cm.
• Wet suction is commonly set around −20 cm H₂O, depending on the order.
• Gentle bubbling in the suction-control chamber usually means suction is working.
• Continuous bubbling in the water-seal chamber usually means an air leak.
• Tidaling in the water-seal chamber usually indicates tube patency.
• No tidaling may indicate obstruction, kinking, clamping, or lung re-expansion.
• Chest tubes should not be routinely clamped.
• The drainage system should remain below chest level.
• Kinks, dependent loops, and loose connections should be corrected.
• Air-removal tubes are directed toward the apex.
• Fluid-removal tubes are directed toward the posterior base.
• Sudden signs of tension pneumothorax require immediate intervention.

Pleural Drainage System Practice Questions

1. What is the main purpose of a pleural drainage system?
A pleural drainage system is used with a chest tube to remove abnormal air, fluid, blood, pus, chyle, or other drainage from the pleural space so the lung can re-expand.

2. What condition occurs when air enters the pleural space?
Air in the pleural space is called a pneumothorax.

3. What condition occurs when blood collects in the pleural space?
Blood in the pleural space is called a hemothorax.

4. What condition occurs when pus collects in the pleural space?
Pus in the pleural space is called an empyema.

5. What condition occurs when chyle collects in the pleural space?
Chyle in the pleural space is called a chylothorax.

6. What are the three main chambers of a traditional pleural drainage system?
The three main chambers are the collection chamber, water-seal chamber, and suction-control chamber.

7. What is the purpose of the collection chamber?
The collection chamber receives and measures fluid, blood, pus, chyle, or other drainage coming from the chest tube.

8. What is the purpose of the water-seal chamber?
The water-seal chamber acts as a one-way valve that allows air to leave the pleural space but prevents air from returning to the chest.

9. What is the purpose of the suction-control chamber?
The suction-control chamber regulates the amount of negative pressure applied to the pleural space.

10. Why should the drainage system be kept below the level of the patient’s chest?
It should be kept below chest level to promote drainage by gravity and reduce the risk of backflow toward the patient.

11. What does bubbling in the water-seal chamber usually indicate in a patient with a pneumothorax?
Bubbling in the water-seal chamber indicates that air is leaving the pleural space through the drainage system.

12. What does continuous bubbling in the water-seal chamber suggest?
Continuous bubbling in the water-seal chamber suggests an air leak in the patient, insertion site, tubing, or drainage system.

13. What does gentle bubbling in the suction-control chamber indicate in a wet suction system?
Gentle bubbling in the suction-control chamber indicates that suction is being applied and the wet suction system is functioning.

14. What does no bubbling in the suction-control chamber suggest when suction is expected?
No bubbling may suggest that suction is off, the tubing is kinked or disconnected, the suction source is inadequate, or the vent is blocked.

15. What is tidaling in a pleural drainage system?
Tidaling is the rise and fall of the water level in the water-seal chamber with breathing or ventilator cycling.

16. What does tidaling usually indicate?
Tidaling usually indicates that the chest tube is patent and communicating with the pleural space.

17. What should be suspected if tidaling suddenly stops?
If tidaling stops, the clinician should suspect possible tube obstruction, kinking, clamping, occlusion by clot or fluid, or lung re-expansion.

18. How is the water-seal chamber commonly filled in a wet system?
The water-seal chamber is commonly filled with sterile water to about the 2 cm mark.

19. What suction level is commonly used with a wet suction-control chamber?
The suction-control chamber is commonly filled to about −20 cm H₂O, depending on the order and manufacturer instructions.

20. What determines the actual suction applied to the pleural space in a wet system?
The suction-control chamber determines the actual suction applied, not simply the wall suction setting.

21. Why should excessive bubbling in the suction-control chamber be avoided?
Excessive bubbling should be avoided because it can increase water evaporation and alter the suction-control level.

22. What should be done if the water level in the suction-control chamber drops?
Sterile water should be added as needed to restore the ordered suction level.

23. Why should the drainage system not be tipped over?
Tipping the system can make drainage measurements inaccurate and may allow fluid to move into the wrong chamber.

24. What type of chest tube placement is used to remove air from the pleural space?
For air removal, the chest tube is usually directed toward the apex of the lung because air rises.

25. What type of chest tube placement is used to remove fluid from the pleural space?
For fluid removal, the chest tube is usually directed toward the posterior base of the lung because fluid collects dependently.

26. What is a tension pneumothorax?
A tension pneumothorax occurs when air enters the pleural space and cannot escape, causing pressure to build inside the chest.

27. Why is a tension pneumothorax considered an emergency?
It can compress the affected lung, shift mediastinal structures, reduce venous return, cause hypotension, and become life-threatening.

28. What breath sound finding may occur on the affected side during a tension pneumothorax?
Breath sounds may be decreased or absent on the affected side.

29. What percussion finding may occur over the affected lung in a pneumothorax?
Hyperresonance may be heard over the affected lung.

30. In a severe tension pneumothorax, which direction can the mediastinum shift?
The mediastinum can shift away from the affected side.

31. What should be done for a tension pneumothorax?
A tension pneumothorax requires immediate decompression, often followed by chest tube insertion connected to a pleural drainage system.

32. Why are larger chest tubes often used for hemothorax?
Larger chest tubes are often used because blood and clots may not drain effectively through small-bore catheters.

33. What does red drainage in the collection chamber suggest?
Red drainage suggests blood, which may occur with hemothorax, trauma, surgery, or active bleeding.

34. What does yellow or green drainage suggest?
Yellow or green drainage may suggest pus from an empyema.

35. What does white or milky drainage suggest?
White or milky drainage may suggest chyle from a chylothorax.

36. What does straw-yellow pleural drainage commonly suggest?
Straw-yellow drainage is commonly associated with pleural effusion fluid.

37. Why should drainage volume be monitored and recorded?
Drainage volume should be monitored to track patient progress, identify sudden changes, and help determine whether the underlying problem is improving.

38. What should be done if there is a sudden significant increase in bloody drainage?
A sudden significant increase in bloody drainage should be reported to the physician or provider immediately.

39. When may chest tube removal be considered based on drainage volume?
Chest tube removal may be considered when drainage has decreased significantly, such as less than about 50 mL in 24 hours, depending on the patient’s condition and provider order.

40. Why should clinicians mark the drainage level on the collection chamber?
Marking the drainage level helps track output over time and makes changes in drainage easier to recognize.

41. What should be done when the collection chamber becomes full?
The drainage unit should be replaced with a new system.

42. Why should chest tube tubing be checked for dependent loops?
Dependent loops can trap fluid and interfere with drainage from the pleural space.

43. Why should chest tube tubing be checked for kinks?
Kinks can obstruct airflow or fluid drainage and may increase the risk of worsening pneumothorax or tension pneumothorax.

44. What does subcutaneous emphysema near the insertion site suggest?
Subcutaneous emphysema may suggest that air is leaking into the tissues around the chest tube site.

45. What does crepitus feel like during chest wall assessment?
Crepitus feels like crackling or popping under the skin.

46. Why should the chest tube insertion distance be documented?
The insertion distance should be documented so clinicians can detect whether the tube has migrated outward.

47. What can happen if the most proximal chest tube hole comes out of the skin?
Air may enter through the tube and mimic or create a persistent air leak.

48. Why is routine chest tube clamping discouraged?
Routine clamping is discouraged because it can block air escape and increase the risk of pneumothorax or tension pneumothorax.

49. When may chest tube clamping be temporarily appropriate?
Temporary clamping may be appropriate when changing the drainage system, but the tube should be unclamped once the new system is functioning.

50. Why should a chest tube generally not be clamped during transport?
Clamping during transport can prevent air from escaping the pleural space and may increase the risk of tension pneumothorax.

51. Why is stripping a chest tube discouraged?
Stripping is discouraged because it can create excessive negative pressure inside the tube and may be harmful to tissue.

52. What is the safer approach if clots are present in the chest tube tubing?
Clots may be gently moved toward the collection chamber according to facility policy, rather than rapidly stripping the tube.

53. What should be done if the chest tube drainage system cracks open?
The system should be replaced as soon as possible while maintaining patient safety and preventing air from entering the pleural space.

54. What should be done if a patient with a leaking pneumothorax becomes disconnected from the drainage system?
The tube should initially be left open so air can escape, then the distal end should be placed into sterile water to create a temporary water seal until a new system is connected.

55. What should be done if a patient without a leaking pneumothorax becomes disconnected from the drainage system?
The distal end of the tube may be temporarily clamped to prevent air from entering the pleural space while a new system is prepared.

56. Why is a temporary water seal useful after accidental disconnection?
A temporary water seal allows pleural air to escape while preventing atmospheric air from being drawn back into the chest.

57. What should be assessed first if continuous bubbling appears in the water-seal chamber?
The system should be assessed for an air leak, including the patient, insertion site, tubing connections, and drainage unit.

58. How can the clinician help determine whether an air leak is coming from the patient or the system?
The clinician can briefly pinch the chest tube near the insertion site and observe whether bubbling in the water-seal chamber stops or continues.

59. What does it mean if bubbling stops when the chest tube is briefly pinched near the insertion site?
It suggests the leak is at the patient, insertion site, or within the chest.

60. What does it mean if bubbling continues after the chest tube is briefly pinched near the insertion site?
It suggests the leak is in the tubing, connections, or drainage system.

61. What should be checked if an air leak is suspected in the drainage system?
The clinician should check for loose connections, cracked tubing, holes, tears, or a malfunctioning drainage unit.

62. What should be done if a loose connection is found in the chest tube drainage system?
The connection should be tightened and secured according to facility policy.

63. What should be done if a hole or tear is found in the drainage tubing?
The area may be temporarily taped while a new drainage system or tubing setup is prepared.

64. Why is the insertion site dressing important in chest tube care?
The dressing helps seal the insertion site and reduces the risk of air entering around the chest tube.

65. What does a loose chest tube dressing increase the risk of?
A loose dressing can allow air to enter the pleural space around the tube and contribute to an air leak.

66. Why should the respiratory therapist monitor the patient during and after chest tube insertion?
The therapist should monitor for respiratory distress, cyanosis, dizziness, bleeding, changes in heart rate, and other signs of deterioration.

67. What patient finding may indicate recurrent pneumothorax after chest tube removal?
Crepitus or subcutaneous emphysema near the insertion site may suggest recurrent air leakage.

68. What does rising peak airway pressure suggest in a mechanically ventilated patient with sudden unilateral decreased breath sounds?
It may suggest a pneumothorax or tension pneumothorax on the affected side.

69. Why are mechanically ventilated patients at risk for pneumothorax?
Positive-pressure ventilation can worsen air leaks or contribute to barotrauma when airway pressures or lung volumes are excessive.

70. How may an air leak be estimated in a patient on volume-controlled ventilation?
The air leak may be estimated by comparing delivered tidal volume with measured exhaled tidal volume.

71. What does a lower exhaled tidal volume than delivered tidal volume suggest in a ventilated patient with a chest tube?
It may suggest that some of the delivered air is escaping through the pleural space and drainage system.

72. Why is air leak measurement less reliable during pressure-controlled ventilation?
A consistent set tidal volume may not be delivered, so clinicians often rely on qualitative signs such as bubbling in the water-seal chamber.

73. What does bubbling that occurs when a patient coughs suggest?
It suggests air may still be leaking through a tear in the lung and exiting through the drainage system.

74. What may it mean when bubbling in the water seal stops after a previous air leak?
It may suggest that the pleural tear has healed, but obstruction should also be ruled out if clinically suspected.

75. Why must the patient’s overall condition be considered when interpreting bubbling and tidaling?
Bubbling and tidaling can reflect improvement, ongoing air leak, obstruction, or system malfunction, so they must be interpreted with the patient’s respiratory status and clinical findings.

76. What is the normal purpose of the pleural space?
The pleural space allows the lungs to move smoothly during breathing while helping maintain contact between the lungs and chest wall.

77. Why can air in the pleural space reduce lung volume?
Air separates the visceral pleura from the parietal pleura, which can prevent the lung from staying expanded against the chest wall.

78. Why can pleural fluid interfere with breathing?
Pleural fluid can compress the lung and limit expansion, which may impair ventilation and oxygenation.

79. What is the role of lymphatic drainage in the pleural space?
Lymphatic drainage normally helps remove excess pleural fluid so abnormal fluid does not accumulate.

80. What can happen when pleural fluid formation exceeds lymphatic removal?
Pleural fluid can accumulate and lead to a pleural effusion or another pleural abnormality.

81. Why is the water seal considered a safety feature?
It prevents outside air from being drawn back into the pleural space while allowing air to leave the chest.

82. Why must clinicians understand the specific drainage unit used in their facility?
Commercial systems vary in design, setup, water levels, suction indicators, and troubleshooting steps.

83. What should be done before connecting suction to a wet drainage system?
The water-seal chamber and suction-control chamber should be filled to the appropriate levels according to the order and manufacturer instructions.

84. Why is sterile water used in the drainage system?
Sterile water helps create the water seal and suction-control level while reducing contamination risk.

85. What should be checked daily in a wet pleural drainage system?
The water levels in the water-seal chamber and suction-control chamber should be checked and maintained.

86. Why can evaporation affect suction control?
If water evaporates from the suction-control chamber, the water level drops and the amount of suction applied may change.

87. What does the suction-control chamber do when wall suction is stronger than the ordered suction level?
It buffers and limits the negative pressure so only the intended suction level is transmitted to the pleural space.

88. Why is it important to avoid touching connectors during setup?
The system connects to the pleural space, so aseptic technique helps reduce the risk of contamination and infection.

89. Why should the respiratory therapist assess breath sounds after chest tube insertion?
Breath sounds help determine whether lung expansion is improving and whether complications such as pneumothorax are present.

90. What should be assessed at the chest tube insertion site?
The site should be assessed for bleeding, drainage, dressing integrity, air leakage, tube migration, and subcutaneous emphysema.

91. What is the significance of decreased chest wall movement on one side?
It may indicate impaired lung expansion on that side, which can occur with pneumothorax or pleural fluid accumulation.

92. Why is hypoxemia concerning in a patient with a chest tube?
Hypoxemia may indicate worsening lung expansion, impaired gas exchange, pneumothorax, obstruction, or another respiratory complication.

93. What does a pressure-relief chamber or valve do in some drainage systems?
It allows excess gas or pressure to escape if the vacuum system fails or becomes disconnected.

94. What problem can occur in a three-chamber system if pressure builds without adequate relief?
Pressure may build until water in the suction-control chamber is forced upward or out of the chamber.

95. Why is a four-chamber system considered safer in some situations?
The additional pressure-relief chamber or valve provides an escape route for excess air or pressure.

96. What is the purpose of connecting a chest tube to wall suction?
Wall suction helps remove air or fluid from the pleural space and promotes lung re-expansion when ordered.

97. Why is the wall suction increased slowly during setup?
It is increased slowly until gentle bubbling appears, which helps confirm suction without causing excessive bubbling or evaporation.

98. What should be done if the patient develops symptoms while the chest tube is clamped?
The clamp should be removed immediately, and the patient and drainage system should be assessed.

99. What is the main exam clue that a pleural drainage system is removing air from a pneumothorax?
Air bubbling through the water-seal chamber is the key clue that pleural air is being removed.

100. What is the overall responsibility of the respiratory therapist with a pleural drainage system?
The respiratory therapist must understand the equipment, monitor the patient and system, recognize abnormal findings, and respond quickly to complications.

Final Thoughts

A pleural drainage system is an important device for removing abnormal air or fluid from the pleural space and helping the lung re-expand. Its safe use depends on understanding the purpose of each chamber, recognizing normal and abnormal bubbling, monitoring tidaling, measuring drainage, and preventing tube obstruction.

The respiratory therapist must also assess the patient closely because changes in the drainage system often reflect changes inside the chest.

Proper setup, careful monitoring, and prompt troubleshooting can prevent serious complications such as recurrent pneumothorax, infection, excessive drainage, or tension pneumothorax.