Anesthesia for Intracranial Anesthesia for Intracranial Aneurysm SurgeryAneurysm Surgery

Pekka O. Talke, MDPekka O. Talke, MD

AneurysmsAneurysms

• 2-5 % population2-5 % population

• 30K SAH/yr30K SAH/yr

• 2/3 get to hospital2/3 get to hospital

• 1/3 in hospital severely disabled or dead1/3 in hospital severely disabled or dead

• Unruptured:1-2%/yr ruptureUnruptured:1-2%/yr rupture

• Ruptured: 50% rerupture within 6 moRuptured: 50% rerupture within 6 mo

• Urgent, not emergent casesUrgent, not emergent cases

SurgeonsSurgeons

• LawtonLawton

Anesthetic GoalsAnesthetic Goals

• Prevent aneurysm rupture (avoid hypertension)Prevent aneurysm rupture (avoid hypertension)

• Decrease ICP (surgical exposure, retraction)Decrease ICP (surgical exposure, retraction)

• Maintain CPP (>70 mmHg)Maintain CPP (>70 mmHg)

• Prevent cerebral ischemia from retraction Prevent cerebral ischemia from retraction

• Good operating conditions (NO movement, brain Good operating conditions (NO movement, brain relaxation for exposure)relaxation for exposure)

Patients, preopPatients, preop

• Symptomatic/asymptomaticSymptomatic/asymptomatic

• Ruptured (SAH grade, myocardial effects), Ruptured (SAH grade, myocardial effects), unrupturedunruptured

• Possibly intubatedPossibly intubated

• Location and size of aneurysmLocation and size of aneurysm

• Intracranial mass effect from SAH (increased ICP)Intracranial mass effect from SAH (increased ICP)

• Neurologic deficits and symptomsNeurologic deficits and symptoms

• Timing, vasospasmTiming, vasospasm

PreopPreop

• One IVOne IV

• Premedicate with up to 2 mg of midazolam if Premedicate with up to 2 mg of midazolam if normal mental status.normal mental status.

• Remind of potential post op intubationRemind of potential post op intubation

• Adequate fluid loading (5 to 7 ml/kg of LR, Adequate fluid loading (5 to 7 ml/kg of LR, angio)angio)

InductionInduction

• Routine monitors

• Propofol or thiopental

• Fentanyl 5 ug/kg in divided doses prior to intubation

• Muscle relaxant (roc).

• Arterial cannula before intubationArterial cannula before intubation

• Avoid hypertension (propofol) and hypotension (CPP, vasospasm)

Induction cont.Induction cont.

• Ceftriaxone 1 gm, 4-10 mg decadron, 1 gm/kg mannitol.Ceftriaxone 1 gm, 4-10 mg decadron, 1 gm/kg mannitol.

• Tape eyes with tagaderms (prep solution)Tape eyes with tagaderms (prep solution)

• Temp probe, foleyTemp probe, foley

• Additional IV (limited access, 300 cc to liters of blood loss)Additional IV (limited access, 300 cc to liters of blood loss)

• Compression stockingsCompression stockings

PositioningPositioning

• Supine, bumpSupine, bump

• Long cases, lots of padding (pink and blue Long cases, lots of padding (pink and blue foam)foam)

• Table turned typically 90 degreesTable turned typically 90 degrees

• Head down?, aeroplaningHead down?, aeroplaning• After draping minimal/no access to face After draping minimal/no access to face

(secure ET well)(secure ET well)

MaintenanceMaintenance

• OxygenOxygen

• Propofol infusion (50-200 ug/kg/min) (SSEPs, EEG)Propofol infusion (50-200 ug/kg/min) (SSEPs, EEG)

• Inhalation agent (<0.25 MAC Isoflurane). Muscle Inhalation agent (<0.25 MAC Isoflurane). Muscle relaxation (vec, panc)relaxation (vec, panc)

• Moderate hyperventilation (ET CO2 30 mmHg)Moderate hyperventilation (ET CO2 30 mmHg)

• Euvolemia to 500 cc more (LR)Euvolemia to 500 cc more (LR)

• Moderate hypothermia (34 oC)Moderate hypothermia (34 oC)

Burst supressionBurst supression

• When requested by surgeonWhen requested by surgeon

• Thiopental 125 mg (5 cc) dosesThiopental 125 mg (5 cc) doses

• Till 70-80% EEG burst supressionTill 70-80% EEG burst supression

• Redose as neededRedose as needed

• Turn fentanyl infusion offTurn fentanyl infusion off

• Reduce propofol infusion rateReduce propofol infusion rate

• Support CPP with phenylephrine infusionSupport CPP with phenylephrine infusion

ClippingClipping

• Temporary clips (golden)Temporary clips (golden)

• Permanent clips (silver)Permanent clips (silver)

• Aneurysm manipulation before clipping (bleed)Aneurysm manipulation before clipping (bleed)

• Record clip on/off timesRecord clip on/off times

• Maintain CPP during temporary clippingMaintain CPP during temporary clipping

• Start closing, warming and more fluid loading after Start closing, warming and more fluid loading after clippingclipping

Toward the endToward the end

• First indication of end of surgery when clip First indication of end of surgery when clip aneurysm (60 min)aneurysm (60 min)

• Normalize CO2 once dura closed or earlier if Normalize CO2 once dura closed or earlier if lots of intracranial spacelots of intracranial space

• Reduce propofol if possible, and titrate in Reduce propofol if possible, and titrate in labetalollabetalol

Toward the end Toward the end cont.cont.

• Turn propofol infusion off about 10 min Turn propofol infusion off about 10 min before wakeupbefore wakeup

• Reverse relaxation once Mayfied pins have Reverse relaxation once Mayfied pins have been removedbeen removed

• Attempt to wakeup patient. Unlikely if more Attempt to wakeup patient. Unlikely if more than 1 gm of thiopental given.than 1 gm of thiopental given.

RecoveryRecovery

• Wake patient up as soon as possibleWake patient up as soon as possible

• Extubate if possibleExtubate if possible

• Prevent post op hypertension (bleed). Prevent post op hypertension (bleed). LabetalolLabetalol

• Transport to ICU with monitor and oxygenTransport to ICU with monitor and oxygen

• Head up positionHead up position

Potential ComplicationsPotential Complications

• Delayed awakening from anesthesiaDelayed awakening from anesthesia

• Cerebral ischemia (retraction, temporary Cerebral ischemia (retraction, temporary clips, vasospasm)clips, vasospasm)

• Brain swellingBrain swelling

• Intraoperative hemorrhageIntraoperative hemorrhage

Aneurysm ruptureAneurysm rupture

• Reasonably commonReasonably common

• Intubation, pinning, skin insicion, surgical Intubation, pinning, skin insicion, surgical manipulationmanipulation

• Maintain intravascular volume (blood in the room, Maintain intravascular volume (blood in the room, get help)get help)

• Maintain CPPMaintain CPP

• Adequate anesthesiaAdequate anesthesia

• Thiopental before temporary clippingThiopental before temporary clipping

VasospasmVasospasm

• Only if SAHOnly if SAH

• 5-14 days after SAH5-14 days after SAH

• Leading cause of SAH morbidity (infarct)Leading cause of SAH morbidity (infarct)

• Maintain CPP at all times (neo infusion, Maintain CPP at all times (neo infusion, volume)volume)

• HHH therapyHHH therapy

• Consider CVP measurementConsider CVP measurement

What’s new?What’s new?

• Retractor pressure Retractor pressure

• Temp controlTemp control

• NormotensionNormotension

Surgical StepsSurgical Steps

• Mayfield pins (stimulation), head positioningMayfield pins (stimulation), head positioning

• Shaving/prepping/local anesthesiaShaving/prepping/local anesthesia

• Skin incision (stimulation, blood loss)Skin incision (stimulation, blood loss)

• Scalp off the bone (most stimulation)Scalp off the bone (most stimulation)

• Burr holes, sawingBurr holes, sawing

• Removing boneRemoving bone

• Open duraOpen dura

• Surgical approach to aneurysm (microscope, Surgical approach to aneurysm (microscope, minimal stimulation, retraction)minimal stimulation, retraction)

Surgical Steps cont.Surgical Steps cont.

• Burst supressionBurst supression

• Temporary clips, permanent clip(s)Temporary clips, permanent clip(s)

• Close (60 min)Close (60 min)

• Dura (water tight)Dura (water tight)

• Bone flapBone flap

• Scalp and skinScalp and skin

• Dressing, remove pinsDressing, remove pins