Transcript Slide 1

The Child with Brain Tumor:
Important Anesthetic Concepts
Hany El-Zahaby, MD
Ain Shams University
Aim
“Highlight the current neuro-physiological concepts and
how to apply it to best of the anesthetic practice for
the child with brain tumor.”
Brain tumors
The second most common solid tumor in childhood.
Posterior fossa tumor
Supratentorial tumor
Suprasellar tumor
Intracranial space
Brain & interstitial
tissues
Blood vessels
CSF
 Translocation of CSF to the distensible spinal subarachnoid
space
 Translocation of blood to scalp veins.
Intracranial Compliance
 The infant with open fontanels and cranial sutures would have
a more compliant intracranial space especially with gradual
increase in volume.
 Full-term neonates ICP is 2-6 mmHg with increasing head
circumference as the first clinical sign of increased ICP.
 Infants presenting with signs and symptoms of intracranial
hypertension have fairly advanced pathology.
 Classic signs of high ICP as papilledema, pupillary dilatation,
hypertension, bradycardia may be absent.
 Headache, irritability & morning vomiting.
 ↓ level of consciousness & abnormal responses to painful
stimuli.
Monitoring
Intraventricular catheters
Subarachnoid bolts/screws
Epidural monitor
Fiberoptic ICP monitor
Herniation Syndromes
1- Defect of calvarium.
2- Interhemispheric falx: Internal
capsule-posterior cerebral A.blindness.
3- Trans-tentorial herniation: 3rd CN
& brain stem compression
leading to pupillary dilatation,
hemiplegia & loss of
consciousness “The uncal
syndrome”.
4- Cerebellar herniation: Brain
stem compression & obstruction
of CSF circulation leading
cardiorespiratory failure.
Cerebral Blood Volume and Cerebral Blood Flow
CPP = MAP – ICP
Neonate CBF
40 ml/100g/min
Child CBF
100 ml/100g/min
Penlucida
Penumbra
Adult CBF
55ml/100g/min
Maintaining COP & CPP is of utmost importance
Cerebrovascular Autoregulation
 Myogenic control of arteriolar
resistance enables brain perfusion
to remain stable despite moderate
changes in MAP & ICP.
 It is lost in acidosis, vessels
supplying tumors, cerebral edema.
 Abrupt ↑BP
Cerebral autoregulation range in neonate
→hemorrhage/cerebral edema.
is 20-60 mmHg
 Worsening cerebral ischemia with
moderate hyperventilation in
children with compromised cerebral
perfusion.
Posterior fossa (infra-tentorial)
tumor (50%)
 Medulloblastoma, cerebellar
astrocytoma, brain stem gliomas
 CSF flow obstruction increasing ICP
 Cranial nerve affection-ataxia
 Arrhythmias-respiratory affection
(late)
 Bradycardia-hypertension-acute
blood loss may complicate the
procedure.
Supra-tentorial tumors (25-30%)
 Astrocytomas, oligodendrogliomas,
ependymomas, and glioblastomas.
 Focal deficits, seizures.
 UMNL → avoid succinyl choline.
 Anticonvulsants.
 Somatosensory evoked potential
needs no Ms. relaxation.
Supra-sellar tumors (15-20%)
 Craniopharyngioma, optic gliomas, pituitary
adenomas, hypothalamic tumors.
 Hypothyroidism/steroid therapy/ diabetes
insipidus.
 Nocturnal enuresis → serum electrolytes
and osmolality.
 Trans-sphenoidal approach.
History
General
Respiratory
Cardiovascular
GIT
Endocrinal
Hematologic
Allergies
Specific
 Seizures
 Headache, Lethargy
 Vomiting, enuresis, anorexia
 Swallowing incoordination
 Visual/hearing impairment
 Motor disability/abnormal
movement
 Medications
Examination
 Level of consciousness
 Motor/sensory function
 Reflexes
 Cranial nerves
 ICP
 Pupillary size/reflex
 Gag reflex/aspiration pneumonia
 Muscle atrophy (receptor up-regulation)
Investigations
 Routine + S. osmolality.
 On individual basis: ABG, CXR, ECG.
 Neuro-radiological studies.
 Preoperative discussions: neurosurgeon, neurophysiologists &
parents.
Premedication/Monitoring
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Transport in head-up position.
Sedation only in OR.
Routine monitoring.
Nerve stimulator on a limb with normal neurologic function.
Arterial catheter: Refering the transducer to external auditary
meatus to estimate CPP.
CVP
 ↑ICP → no head-down → Femoral vein.
 If no ↑ICP → subclavian vein is a reasonable choice.
 Peripherally inserted central lines.
 Wide-bore long saphenous vein catheter.
“Early removal of all lines especially the arterial line”.
Induction
 Uncooperative child with intracranial tumor and moderately
decreased intracranial compliance who is agitated, resistant
to parental separation child with no IV??
IV-IV-IV
 Thiopental/propofol
 Sevoflurane
 Fentanyl 2-3 µ/kg
 Atracurium/cisatracurium/rocuronium
Airway Management and Intubation
Aim: Effective and smooth airway management avoids increase
ICP, hypoxemia, hypercarbia, and coughing.
Oral for supine/nasal for prone.
Securing ETT – folded gauze.
Check bilateral air entry with head flexion & after final
positioning.
Open OGT.
Pad the eyes.
Access to ETT/connections/vascular catheter sites.
Prone position
Avoid abdominal compression.
Venous congestion of face,
tongue, and neck .
Decreased lung compliance.
Avoid extreme flexion of head:
• brainstem compression.
• cervical cord ischemia.
• endobronchial intubation.
 Local infiltration: 0.25% bupivacaine with 1 : 200,000
epinephrine 1 ml/kg.
 LA: equal volumes of bupivacaine 0.5% and epinephrine
1:100,000 (1mg/100ml saline)
Anesthetics that decrease ICP and CMRO2 and maintain CPP
are desirable.
“The choice of anesthetic agents for
maintenance of anesthesia has been shown
not to affect the outcome of neurosurgical
procedures.”
“Todd MM, Warner DS, Sokoll MD, et al. A prospective, comparative trial of
three anesthetics for elective supratentorial craniotomy. Anesthesiology
1993;78:1005– 20.”
Blood and Fluid Management
Early transfusion avoids severe anemia & hypoperfusion.
Doubling oncotic pressure has less effect on preventing
brain edema than 1 meq/L increase in serum sodium.
Cerebral edema through disrupted BBB is worsened by
excessive administration of hypotonic IV fluids.
Normal saline/Ringer’s solution (308 mOsm/L) is preferred
than LR (285mOsm/L).
 No glucose-containing solution is used even for extended
surgeries except in:
Diabetic child.
Severely debilitated child.
Child on TPN.
When given, no more than the maintenance.
 Normovolemia should be maintained throughout the
procedure.
Temperature control
 Maintaining normal temperature is the goal despite beneficial
effect of mild hypothermia on CMRO2.
 Forced hot air warming mattresses is the most effective mean.
VAE
 Occurs when there is pressure
gradient between the operative
site and the heart especially
with low CVP.
 Flood with saline, bone wax,
Trendelenburg position, fluid
bolus, PEEP and aspirate air
through a central venous
catheter.
Emergence
 PONV: Opioids and blood in the CSF versus dexamethazone
and granisetrone.
 No residual muscle paralysis is accepted on extubation.
 Full awakening before extubation.
 Neurological assessment in OR.
“The child with brain tumor is expected to
leave OR at least as neurologically as before
operation”.
In unconscious child postoperatively, ICP
should be monitored, ventilation continued
and immediate CT-scan should be done.
Postoperative
 Regular paracetamol & small doses of opioids.
 Intraoperative fentanyl usually covers the early postoperative
period.
 Diabetes incipidus may need vasopressin (1-10 mU/kg/hr).
 CT and MRI are often performed 1 or 2 days after craniotomy.
Neuro-protection
Goals:
Avoid cerebral edema
Avoid cerebral hypoxia
Avoid cerebral hypo-perfusion
Avoid cerebral hyper-metabolism
Avoid neuronal membrane damage
Take-home messages
 Maintain
– Normo-volemia.
– Normo-osmolality.
– Normo-thermia.
– Normo-ventilation.
– Normal CPP.
Thank You
2012