Chest Drain Respiratory Swing — FRCA Final MCQ

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EasyTrauma & Emergency AnaesthesiaChest Drain Respiratory SwingFRCA Final

A 35-year-old man (ASA I, 70 kg) sustains a traumatic pneumothorax. A chest drain is inserted. On the underwater seal drainage system, the fluid in the bottle swings with respiration. What does respiratory swing indicate?

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Correct answer: B — Haemothorax is developing

Respiratory swing (the fluid column in the underwater seal oscillates with breathing – falling during inspiration and rising during expiration in a spontaneously breathing patient, opposite in ventilated patients) indicates that the drain is in the pleural space, is patent, and is communicating with the intrapleural pressure changes during respiration. ABSENCE of respiratory swing suggests: drain blockage (clot, kink), drain not in the pleural space, or lung fully re-expanded and adherent to the chest wall. Continuous bubbling through the underwater seal indicates an air leak (from the lung or from a connection leak in the system).

Reference: BTS – 2023 – Pleural disease guidelines; ATLS – 2018 – 10th edition