a 31-yr - old , 174 cm , 92 kg male was admitted after sustaining a c7 fracture due to a fall down injury . magnetic resonance imaging revealed a bursting fracture with multiple bony fragmentations of the c7 vertebral body along with spinal canal stenosis and compression of the spinal cord . the patient was scheduled for emergency anterior cervical corpectomy and fusion , with being placed in the supine position , for the unstable bursting fracture and the incomplete cervical cord injury . the patient had no known history of chronic obstructive pulmonary disease , asthma or chronic respiratory diseases . routine anesthetic monitors were applied at the operating room , and anesthesia was induced with remifentanil , propofol and rocuronium . face mask ventilation was successful with the capnographic tracing showing the end - tidal co2 to be around 35 mmhg , the vt was 500 - 600 ml and the peak airway pressure was around 20 cmh2o . the patient 's trachea was intubated orally using a reinforced 8.0-mm ett using the lightwand ( surch - lite , aaron medical industry , st.petersburg , fl , usa ) . ausculatatory bilateral breath sounds could not be confirmed and the ett was removed due to the suspicion of having intubated the esophagus . the ett was reinserted by using the lightwand and diminished , coarse breath sounds were auscultated distally . capnography also showed the partial pressure of co2 , and so the ett was secured at the 23 cm mark at the patient 's upper incisors and the patient 's lungs were mechanically ventilated with a vt of 750 ml without positive end - expiratory pressure ( peep ) . yet the ventilator was able to deliver a vt of only 500 ml with a peak inspiratory airway pressure ( pip ) of 35 cmh2o . the limit of pip was reset to 45 cmh2o without any increase in the vt . a suction catheter was easily passed through the ett and thick secretions were suctioned , but there still was no change in the vt or pip . we decided to change the reinforced ett to a plain ett due to the suspicion of a mucous plug . also the presence of a ' murphy eye ' on the plain ett would decrease the risk of occlusion . this time tracheal intubation was performed under direct laryngoscopy in order to confirm an appropriate depth of the ett . the patient 's lungs were mechanically ventilated , but the pip was still high and the vt was still low . eight cmh2o peep was added , the mode of the ventilator was changed from cmv to pcv with the pressure set at 40 cmh2o and endotracheal suction was done , but there was no improvement . fiberoptic bronchoscopic ( fob ) examination identified that the bevel of the ett orifice was abutting against the tracheal wall ( fig . first the patient 's neck was positioned to the surgical position ( neck extension ) and then the ett was withdrawn 1 cm . despite that the tip of the ett and the wall of trachea were abutting to one another , we kept withdrawing the ett under fob examination . when the ventilator was turned on , the vt was still low and the endoluminal view under fob remained unchanged . we next tried to rotate the ett since the patient 's head could not be rotated due to the surgical position . the ett was turned 90 counterclockwise to disengage the bevel from the tracheal wall , but the tip of ett was not turned and we tried to rotate the ett 180 , but the ett became kinked instead . we determined that a single lumen ett tracheal tube could not be positioned properly and so a double - lumen ett was placed . the pip immediately dropped from 48 ( cmv mode ) to 23 cmh2o with a vt of 750 ml . the pip remained stable throughout the surgical period and the patient 's trachea was extubated at the end of surgery . in neonates , the distal orifice of an uncuffed ett abuts against the tracheal wall and causes frequent obstruction at the end of the ett . but for adults , a cuffed ett does not allow free movements of the ett in the trachea and obstruction does not occur as often as that in young babies . numerous reports exist concerning tube - tip displacement during head - neck movement in children [ 3 - 5 ] . head movement shifts the secured ett within the trachea and causes downward movement during neck flexion and upward movement during neck extension . yet for adults , unknown anatomical anomaly seems to cause tube malposition or difficulty in ventilation [ 7 - 9 ] . the reported cases of patients with a tracheal bronchus emphasize the importance of correct positioning of the ett . in this case , the patient did not have any anatomical abnormality that would cause difficulty when ventilating the lungs . reported a case of a tube orifice abutting on the tracheal wall in a patient with forestier 's disease . due to large osteophytes of the cervical vertebral bodies of c5 , 6 and 7 , the trachea was deviated on extension of the neck and this caused the bevel of the tube to abut against the tracheal wall . the c7 fracture with multiple bony fragmentation of the c7 vertebral body in our patient might have caused some anatomical alteration , which could have caused the difficulty in ventilation . yet there was no obvious tracheal deviation seen on the preoperative chest x - ray ( fig . further , the difficulty to ventilate the lungs did not improve or worsen because of head extension . jordi ritz et al .   mentioned that inadvertent tube malposition occurs more often with pre - formed tubes when compared to that for straight tubes . it seems that the curvature of the ett was angled in such a way that the beveled tip of the ett and the wall of trachea embraced tightly to each other , and not enough vt was delivered to the patient . we also did not suspect abutment of the ett on the tracheal wall and it took a while to decide to perform an examination under fob because a vt of 500 ml was being delivered to the patient . it is important to notice that even an appropriately placed ett may get obstructed due to its left sided bevel . it is still unclear why enough vt was not delivered to the patient when we changed the reinforced tube to a plain ett with a murphy eye . probably a murphy eye simply was not able to deliver a vt of 750 ml and the surgical position ( neck extension ) did not assist in improving the vt . once airway problems were encountered in an intubated patient , it is important to consider both mechanical and pathologic factors . especially for this case , just enough vt was delivered to the patient and the problem could have been overlooked because the patient was obese ( bmi > 30 ) . fob is a useful tool to confirm the position of the ett and to correctly place it . yet the most important thing for the anesthesiologist is to act as a thoughtful , thorough investigator . if there is any doubt about the airway , then one must evaluate the problem and meticulously manage it before the operation starts .
we experienced difficulty in ventilating the lungs of a patient after tracheal intubation . 
 after intubation , an insufficient amount of tidal volume ( vt ) was delivered to the patient and the fiberoptic bronchoscopic examination identified partial abutment of the endotracheal tube ( ett ) orifice against the tracheal wall . 
 after various attempts to correctly place the ett , a double - lumen endotracheal tube was placed to achieve a sufficient vt . 
 it is important to notice that even an appropriately placed ett may get obstructed due to the left sided bevel at its tip .