Page 12 - CASA Bulletin of Anesthesiologisy 2022 9(6)-1 (3)

CASA Bulletin of Anesthesiology

Anesthetic management

Two large-bore IVs, arterial line and urinary catheter are usually placed after the patient is
sedated. A comprehensive plan for supporting or securing the airway emergently should be in
place. Patients who are allowed to breathe spontaneously with supplemental oxygen need to be
watched for airway obstruction. High-flow nasal cannula is an air oxygen blender supplying
humidified air and oxygen mixture with control of FiO2 from 0.2 to 1.0. It has recently been
reported to facilitate awake craniotomy in the morbid obese patients 15, 16 . Nasopharyngeal or
oropharyngeal airway may be inserted to alleviate airway obstruction, however, the risks of nose
bleeding, coughing and increased airway secretion should be kept in mind. Respiratory
insufficiency and hypercapnia may lead to elevated ICP and cerebral edema. If airway
obstruction aggravates rapidly to critical situation, assisted ventilation with an LMA or ETT
insertion will be indicated. Advanced airway equipment (video laryngoscope, fiberoptic
bronchoscope) should be readily available to assist emergent intubation in a patient whose head
is pinned and turned in semi-lateral position.

Awake craniotomy performed in the interventional MRI suite (IMRIS) allows identification
of residual tumor by repeated imaging during surgery. The combination of awake craniotomy
and intraoperative MRI facilitates the dual goals of maximal tumor removal with minimal
functional consequences 17, 18 . In many centers, an LMA is placed before each intraoperative MRI
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become invisible and inaccessible after the he or she is in the MRI scanner.

The mainstay of analgesia for awake craniotomy is a regional block. Incisional pain can be
managed with local anesthetics infiltration along the incision line and the pin sites. Many centers
use scalp blocks to more efficiently block the six nerves which provide sensory innervation to
the scalp (the greater and lesser occipital nerves, great auricular, auriculotemporal,
zygomaticotemporal, supratrochlear and supraorbital nerves) . However, even with successful
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scalp blocks, patients often experience pain during surgical resection. Usually, these sensations
are associated with manipulations of the skull-base structures or traction of pain-sensitive
structures . During surgical resection, the surgeons may infiltrate the areas close to inflections
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of the dura and major arteries (the dura mater of the skull base, the falx cerebri, and the
leptomeninges of the lateral fissure and neighboring sulci) with local anesthetics, as those areas
are sensitive to pain . In addition, the surgeons need to avoid traction of pain-sensitive
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Besides the surgical manipulation, there are other resources of discomfort or irritation that an
anesthesiologist must keep in mind and attempt to alleviate as much as possible to facilitate a
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from urinary catheter, lines (arterial line, IVs), tight-fitting oxygen mask or nasal trumpet,
inability to see the surroundings. It would be helpful to provide mouth moisture swab, warm
blanket, adequate padding to pressure points, face tent (instead of tight-fitting oxygen mask),
numbing the nostril before insertion of nasal trumpet, and tent the drape upward from the patient
for better ’ ’
could be played in the operating room to help to alleviate their anxiety. Verbal guidance and
reassurance should be offered throughout the awake portion during the neurological testing, he or
she must be reassured that involuntary movements and speech patterns may occur as a result of
cortical stimulation by the surgical team.

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