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Designed, Produced, and maintained (Edition 12, 2022) by 

Bhavani Shankar Kodali MD

Updated September 2022

Endobronchial intubation

Endobronchial intubation

Right mainstem intubation

Endotracheal tube pulled back into the trachea




A biphasic carbon dioxide elimination waveform recorded in a patient with no known lung disease who was found to have a right main-stem bronchial intubation. 

This capnogram probably occurred as the tip of the endotracheal tube changed moved in out of right main bronchus during respiratory cycle. This resulted in partial obstruction to gases from left lung thereby prolonging  expiratory time from left lung. The initial peak is due to the carbon dioxide  from well ventilated right lung. The second peak is most likely due to prolonged expiratory time of poorly ventilated left lung.


Gilbert D, Benumof JL. Biphasic carbon dioxide elimination waveform with right mainstem bronchial intubation.  Anesth Analg 1989;69:829-32 (with permission).