Unrecognized bronchial intubation associated with the uncuffed pediatric tracheal tube with bilateral Murphy eyes

Unreliability of breath sounds auscultation after intubation is reportedly mainly related to the presence of the Murphy eye. This study was performed to ascertain whether an uncuffed pediatric tracheal tube with bilateral Murphy eyes increases the risk of unrecognized bronchial intubation, compared to an uncuffed tube without eyes.

Following induction of anesthesia in 50 toddlers, either an uncuffed tube without eyes or an uncuffed tube with bilateral eyes was inserted into the trachea. The tube was then slowly advanced while breath sounds were auscultated using a stethoscope. In study 1, when breath sounds changed and disappeared, the distance from the carina to the tube tip was measured using a fiberoptic bronchoscope. In study 2, when breath sounds changed, the tracheal tube was withdrawn 5, 10, 15 and 20 mm while using a fiberoptic bronchoscope to ascertain whether bronchial intubation had occurred.

When breath sounds changed and disappeared, the tip of the tube with bilateral eyes was positioned more deeply below the carina than that of the tube without eyes. When the tube was withdrawn 10 mm from the point at which breath sounds changed, frequencies of bronchial intubation were 13% and 80% in the no eyes and double eyes groups, respectively.

An uncuffed pediatric tracheal tube with bilateral Murphy eyes reduces the ability of breath sounds auscultation to detect bronchial intubation and may increase the risk of unrecognized bronchial intubation compared to an uncuffed tube without eyes.