Page 18 - CASA Bulletin of Anesthesiology Vol 9 (4) 2022 (3)

CASA Bulletin of Anesthesiology

The MRI anesthetic plan involved Monitored Anesthesia Care with a propofol induction (one
milligram per kilogram) and propofol maintenance (250 micrograms per kilogram per minute).
This included standard ASA monitors, an oxygen source w/ CO2 monitoring, a propofol infusion
pump, and an Oropharyngeal (OP) and/or nasopharyngeal (NP) airway. Per our practice,
appropriately sized airway equipment, medications, and resources were readied in the event of
the need to convert to general endotracheal anesthesia. Upon induction, the patient developed an
obstructive breathing pattern not alleviated by a nasopharyngeal or oropharyngeal airway. The
decision was made to place an appropriately sized laryngeal mask airway and continue with the
MRI. Twenty minutes into the MRI, the patient was still experiencing an obstructive breathing
pattern with increasingly elevated end tidal carbon dioxide (EtCO2). All other vital signs were
within age appropriate limits. Direct laryngoscopy (DL) disclosed the etiology of the obstruction
and a large 2 x 2 cm right supraglottic mass was noted deviating the right vocal cord and
obstructing the glottis inlet by nearly 80% (Figure 1). In light of this new finding and the
difficulty in maintaining satisfactory spontaneous ventilation, the patient was intubated with a
4.0 cuffed endotracheal tube (ETT) after manipulating the mass. The MRI was then completed
under general anesthesia.

MRI imaging of the cervical region confirmed the presence of a previously undiagnosed
supraglottic mass compressing the airway and vocal cords and obstructing the glottis (Figure 1 &
2). An otolaryngologist was called to evaluate the patient’s airway while still under anesthesia
and noted the 2 cm supraglottic mass arising from the right laryngeal surface of the epiglottis
causing significant deviation and narrowing of the patient’s airway. At the conclusion of the
case, the endotracheal tube was left in place and the patient was brought to the ICU. The patient
was subsequently transferred to the PICU at Children National Medical Center for further
evaluation and treatment.

At Children’s National Medical Center, the patient was sedated, received intravenous
dexamethasone and remained intubated on minimal ventilation settings overnight. The patient
was extubated to room air by the PICU team without incident, and an otolaryngology consult
was obtained. Although the patient had returned to his pre-anesthesia baseline state of breathing
comfortably without stridor or retractions, the bedside flexible fiberoptic laryngoscopy revealed
an alarming degree of obstruction by the supraglottic submucosal mass that completely
precluded a view of the true vocal cords (Figure 3). The patient was taken urgently to the OR for
direct laryngoscopy, bronchoscopy, and endoscopic resection of the obstructing supraglottic
mass. General anesthesia was induced via mask inhalation. The larynx was suspended with a
Lindholm laryngoscope and the patient ventilated spontaneously. The submucosal mass was
found arising from the right laryngeal surface of the epiglottis and aryepiglottic fold, and
extended to the right arytenoid region precluding the view of the vocal cords. The mass was
compressible and a 4-millimeter Hopkins rod telescope was passed easily beyond it to confirm
that the remainder of the airway was normal to the carina. Local anesthetic was infiltrated into
the mucosa overlying the mass. A mucosal incision was created with a microlaryngeal knife,
and the mucosa was dissected from the mass. Initially, Coblation and microdebrider technology
were employed to debulk the mass, however the firm lesion could not be easily removed with
these instruments, so the decision was made to convert to CO2 laser resection. A laser-safe ETT
was inserted, and the patient was initiated on heliox. The laser was very effective in debulking

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