Placement of a double lumen tube for lung surgery is best confirmed by –
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Best confirmation of tracheal placement (i.e. detection whether tube is in trachea or esophagus) → capnography (end tidal CO2)
Best confirmation of double lumen tube placement (whether in trachea or bronchus) → flexible fibreoptic bronchoscopy.
EtCO2
Airway pressure measurement
Clinically by auscultation
Bronchoscopy