How to connect a suction device (e.g. Sinapi) to a chest tube?

Connecting a Suction Device (Sinapi) to a Chest Tube

All chest tubes must be connected to a unidirectional flow drainage system (such as an underwater seal bottle) that is kept below the level of the patient's chest at all times, and if suction is applied, it should be done via the underwater seal at a pressure of 5-10 cm H₂O. 1

Essential Connection Steps

Initial Setup

• Connect the chest tube to an underwater seal drainage system first - never connect suction directly to the chest tube 1
• The underwater seal bottle contains a tube placed under water at a depth of approximately 1-2 cm, with a side vent that either allows escape of air or connects to a suction pump 1
• Keep the drainage system below the level of the patient's chest at all times to prevent backflow into the pleural space 1, 2

Applying Suction

• Suction should be applied via the underwater seal system, not directly to the chest tube 1
• Use low-pressure suction at 5-10 cm H₂O - this low pressure reduces the likelihood of the drain becoming blocked with debris 1, 3
• Appropriately trained nursing staff must supervise the use of chest drain suction 1

When to Use Suction vs Water Seal

Water Seal First

• Start with water seal drainage (gravity drainage) without suction initially 1
• Apply suction only if the lung fails to reexpand with water seal drainage alone 1
• Some clinicians apply suction immediately after chest tube placement, though this is less preferred 1

Indications for Suction

• The indications for suction in pleural infection management are unclear, though it is commonly believed to improve drainage 1
• Suction may be beneficial for persistent air leaks or when the lung fails to reexpand with water seal alone 1, 3

Critical Safety Considerations

Never Clamp a Bubbling Drain

• A bubbling chest drain should never be clamped - this can convert a simple pneumothorax into a life-threatening tension pneumothorax 1, 3, 2
• Bubbling indicates air in the pleural space (pyopneumothorax) or a continued visceral pleural air leak 1, 3

Disconnecting for Mobility

• Brief disconnection from suction is acceptable for radiographs or patient mobilization, provided the underwater seal bottle remains below chest level 1
• Ensure adequate instructions are given to patient, family, and staff regarding keeping the bottle below chest level 1

Emergency Unclamping

• If a drain is clamped (e.g., after fibrinolytic instillation), immediately unclamp if the patient develops breathlessness or chest pain 1

Monitoring Tube Function

Assessing Patency

• The respiratory swing in the fluid within the chest tube confirms tube patency and proper positioning in the pleural cavity 1, 3
• If there is sudden cessation of drainage, check for obstruction by flushing the tube 1, 2
• Continuous bubbling may indicate a visceral pleural air leak or that the drain is partially out of the thorax with one hole open to atmosphere 1

Specialized Ward Management

• Patients with chest drains should be managed on specialist wards by staff trained in chest drain management 1, 2

Common Pitfalls to Avoid

• Never apply suction directly to the chest tube - always use an underwater seal system as an intermediary 1
• Do not use excessive suction pressure (>10 cm H₂O) as this increases risk of drain blockage with debris 1, 3
• Avoid clamping any chest drain that is bubbling, as this creates risk of tension pneumothorax 1, 3, 2
• Never allow the drainage bottle to rise above the level of the patient's chest 1, 2