Anesthesia for Intracranial
Aneurysm Surgery
Pekka O. Talke, MD
Aneurysms
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2-5 % population
30K SAH/yr
2/3 get to hospital
1/3 in hospital severely disabled or dead
Unruptured:1-2%/yr rupture
Ruptured: 50% rerupture within 6 mo
• Urgent, not emergent cases
Surgeons
• Lawton
Anesthetic Goals
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Prevent aneurysm rupture (avoid hypertension)
Decrease ICP (surgical exposure, retraction)
Maintain CPP (>70 mmHg)
Prevent cerebral ischemia from retraction
Good operating conditions (NO movement, brain
relaxation for exposure)
Patients, preop
• Symptomatic/asymptomatic
• Ruptured (SAH grade, myocardial effects),
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unruptured
Possibly intubated
Location and size of aneurysm
Intracranial mass effect from SAH (increased ICP)
Neurologic deficits and symptoms
Timing, vasospasm
Preop
• One IV
• Premedicate with up to 2 mg of midazolam if
normal mental status.
• Remind of potential post op intubation
• Adequate fluid loading (5 to 7 ml/kg of LR,
angio)
Induction
• Routine monitors
• Propofol or thiopental
• Fentanyl 5 ug/kg in divided doses prior to
intubation
• Muscle relaxant (roc).
• Arterial cannula before intubation
• Avoid hypertension (propofol) and
hypotension (CPP, vasospasm)
Induction cont.
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Ceftriaxone 1 gm, 4-10 mg decadron, 1 gm/kg mannitol.
Tape eyes with tagaderms (prep solution)
Temp probe, foley
Additional IV (limited access, 300 cc to liters of blood loss)
Compression stockings
Positioning
• Supine, bump
• Long cases, lots of padding (pink and blue
foam)
• Table turned typically 90 degrees
• Head down?, aeroplaning
• After draping minimal/no access to face
(secure ET well)
Maintenance
• Oxygen
• Propofol infusion (50-200 ug/kg/min) (SSEPs, EEG)
• Inhalation agent (<0.25 MAC Isoflurane). Muscle
relaxation (vec, panc)
• Moderate hyperventilation (ET CO2 30 mmHg)
• Euvolemia to 500 cc more (LR)
• Moderate hypothermia (34 oC)
Burst supression
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When requested by surgeon
Thiopental 125 mg (5 cc) doses
Till 70-80% EEG burst supression
Redose as needed
Turn fentanyl infusion off
Reduce propofol infusion rate
Support CPP with phenylephrine infusion
Clipping
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Temporary clips (golden)
Permanent clips (silver)
Aneurysm manipulation before clipping (bleed)
Record clip on/off times
Maintain CPP during temporary clipping
Start closing, warming and more fluid loading after
clipping
Toward the end
• First indication of end of surgery when clip
aneurysm (60 min)
• Normalize CO2 once dura closed or earlier if
lots of intracranial space
• Reduce propofol if possible, and titrate in
labetalol
Toward the end cont.
• Turn propofol infusion off about 10 min
before wakeup
• Reverse relaxation once Mayfied pins have
been removed
• Attempt to wakeup patient. Unlikely if more
than 1 gm of thiopental given.
Recovery
• Wake patient up as soon as possible
• Extubate if possible
• Prevent post op hypertension (bleed).
Labetalol
• Transport to ICU with monitor and oxygen
• Head up position
Potential Complications
• Delayed awakening from anesthesia
• Cerebral ischemia (retraction, temporary
clips, vasospasm)
• Brain swelling
• Intraoperative hemorrhage
Aneurysm rupture
• Reasonably common
• Intubation, pinning, skin insicion, surgical
manipulation
• Maintain intravascular volume (blood in the room,
get help)
• Maintain CPP
• Adequate anesthesia
• Thiopental before temporary clipping
Vasospasm
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Only if SAH
5-14 days after SAH
Leading cause of SAH morbidity (infarct)
Maintain CPP at all times (neo infusion,
volume)
• HHH therapy
• Consider CVP measurement
What’s new?
• Retractor pressure
• Temp control
• Normotension
Surgical Steps
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Mayfield pins (stimulation), head positioning
Shaving/prepping/local anesthesia
Skin incision (stimulation, blood loss)
Scalp off the bone (most stimulation)
Burr holes, sawing
Removing bone
Open dura
Surgical approach to aneurysm (microscope,
minimal stimulation, retraction)
Surgical Steps cont.
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Burst supression
Temporary clips, permanent clip(s)
Close (60 min)
Dura (water tight)
Bone flap
Scalp and skin
Dressing, remove pins