Dr S Parthasarathy MD DA DNB MD Acu Dip DiabDCA Dip Software statisticsPhd physio Mahatma Gandhi Medical college and research institute puducherry India ID: 935908
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Slide1
Anaesthesia for intracranial vascular surgery
Dr. S. Parthasarathy
MD., DA., DNB, MD (
Acu
),
Dip.
Diab.DCA
, Dip. Software
statistics,Phd
(
physio
)
Mahatma Gandhi Medical college and research institute ,
puducherry
, India
What is it ?? A localized dilation or ballooning of blood vessels
Dr
SPS
Slide3Incidence and sites
Incidence : 1 to 6%
•Incidence of ruptured aneurysm: 12/100,000
•Age: any age, peaks 40 - 60.
•Sex: M/F 2:3 Sites : 30% ICA
40% ACA( Anterior Communicating) 20% MCA
10%
Vertebro
-basilar systems
Slide4Anterior – 85 %
85 %
Types
Berry (
pedunculated
)
Fusiform
Dissecting
Slide6Mostly asymptomatic
•Subarachnoid hemorrhage (SAH) due to
aneurysmal
rupture
–Lethal event: 25% don’t even get to the hospital
–In hospital mortality rate up to 50%
–Most survivors have permanent disability
Size – < 12 mm , 12 to 24 mm, > 24 mm
Neuronal injury due to bleed
Vasospasm
Rebleeds
The three main predictors of mortality and dependence impaired level of consciousness on admission,
advanced age,
and large volume of blood on initial cranial computed tomography
Slide8Clinical features
Incidental finding if un ruptured
Hematoma and edema
Ruptured: sudden severe headache “worse headache of my life”, nausea, vision impairment, vomiting, & LOC
Hydrocephalus- blood clots on Subarachnoid granulations & ventricles ↓ CSF absorption & obstruct CSF drainage
Increased ICP , stroke Lethal event: 25% don’t even get to the hospital
Slide9Hunt and hess scale
2
Mortality
35 %
Slide10Fischer - CT scan based features
Slide11World federation of neuro surgeons
Slide12Vasospasm- 13.5% cause of mortality & morbidity.
Most feared complication of SAH
•Occurs 1 to 2 weeks following initial hemorrhage
Patho
physiology not well understood
Blood in SAS→ inflammation → entrapped macrophages and neutrophils →
endothelins
& free radicals → vasospasm → stroke
New onset
neuro
signs
Slide13Vasospasm
Magnetic resonance angiography (MRA)
Ct angiography
Transcranial
doppler
ultrasonography (TCDs) Intra-arterial digital subtraction angiography GOLD STANDARD but invasive
Slide14Nimodipine
Improve outcome in vasospasm
Oral 60mg 4Hly, max dose 360mg for 21 days
IV 1mg/hr during the first 6 hrs,
increase gradually to max 2mg/hr
Maintain SBP 130-150mmhgrisk of hypotensioncentral line to avoid
thrombophlebitis
.
Slide15Hypertension,
hypervolumia
,
hemodilution
( 3 H )
SBP 120-150 mmhg
in unclipped
160-200 mmHg in clipped aneurysm.
CVP 8-12mmHg
HCT 30-35%
Intraarterial
papaverine
Rebleeds
The overall incidence of re bleeding is 11%.
1 – 12 days
Deterioration
70 % mortality
Prevention
BP maintain , seizure control ,ICP maintenance
Slide17What should we do ??
Slide18From outside
Slide19Or from inside
Thrombogenic
– new
intima
will grow inside
Slide20When to touch 0- 3 days
4 – 10 days
Controversial
Slide21Preoperative evaluation
Careful medical history
Physical examination
Baseline BP , fluid status
Hyponatremia (brain
natriuretic peptide) Prolonged bed rest runs the risk of
atelectasis
and pneumonia .
CNS examination
Slide22Pre op work up
Investigations --- for the diagnosis
Routine + ECG, ECHO,
CxR
, coagulation profile T wave inversion & ST depression (most common), Prolong QT (atrial
& ventricular dysrhythmias) -- catecholamine surge
Pregnancy test ( pregnant ruptures the
aneurysm
)
Talk to the surgeon also
Slide23Neuro radiology
Cerebral Angiogram
Site of the aneurysm
Prepare for
intraop
positioning, surgical exposure &
monitoring
CT scan
Amount of subarachnoid blood in the basal cisterns
is good predictor of delayed vasospasm
Increase ICP from IC
haemorrhage
, hydrocephalus
or cerebral
oedema
TCD
facilitate vasospasm management
.
Slide24Premedication
Calcium channel-blocking drugs, anticonvulsants, and steroids are continued.
No sedatives
No narcotics
Possible acid aspiration prophylaxis
preoperative administration of erythropoietin in elective cases might reduce injury from reversible ischemia during temporary clipping
Slide25Cardiac evaluation
Elevated
Troponin
17-28%
Elevated CKMB 37%
Echo LV dysfunction Syndrome of neurogenic
-stunned myocardium
Cardiogenic
shock
pulmonary
oedema
But OK – don’t postpone – no added treatment
Slide26Monitoring
CVS : ECG, Arterial line (IBP), CVP (
cubital
fossa)
RESP : SpO2, End tidal CO2, oesophageal stethoscope
NEUROMUSCULAR : Train of 4 (by PNS) (it is essential that these patients do not move)
CNS : Either BIS/EEG or EPs
RENAL : U/O, all these patients are catheterised the U/O provides an indication that the diuretics are working
Slide27Monitoring
brain temperature
Intermittent arterial blood gases, glucose, electrolytes,
osmolality
, hematocrit
, urine output EEG evoked potentials – duration of occlusion? IV
anaesthetics
better
Jugular bulb oxygen monitoring can also be helpful in patients at risk for global cerebral ischemia.
Slide28Slide29Can we place the leads ??
SSEP monitoring has mostly been used during aneurysm surgery in the territory of both anterior and posterior cerebral circulation,
BAEP monitoring has been used during operations in the territory of the vertebral-basilar circulation
.
Slide30Anesthetic Management
Goals
Decrease
transmural
pressure gradient
Don’t try to control ICP much !!
Slide31Goals maintaining adequate CPP and cerebral oxygenation;
preventing the development of a “tight” brain from cerebral edema or vascular engorgement
.
Slide32Induction !!!
Slide33Induction
Thio
– 5- 6 mg/Kg
Smooth induction – narcotics
IV lignocaine or
esmolol Scoline – OK
Vecuronium
– complete muscle relaxation
Local and
fentanyl
for pinning
Normotension
Maintenance
Nitrous ?? ,
fentanyl
,
propofol - infusion BP should be kept within previously defined limits according to the patient’s baseline BP. Target is usually 20 mm Hg below baseline
Prior Beta blockade may help
Mannitol
(1.5 gm/kg) combined with
Frusemide
(0.3mg/kg) is given to shrink the brain
Slide35Crucial times
Securing of head with Mayfield pins
Skin Incision
Periosteal
Flap elevation and Bone cutting.Narcotic,
propofol , Local
Slide36The basics of brain slackness
crucial for safe surgical dissection to proceed.
implement moderate
hypocapnia
(PaCO2 25–30 mmHg);
elevate the head position; Add diuretics and mannitol
;
Drain spinal fluid;
Avoid cerebral vasodilators
Slide37BP ?? !! Before clipping – get down the BP
After clipping - increase to just above baseline is acceptable – 10 minutes
Hypothermia – not acceptable – vasospasm is more common
Slide38Slide39Intra op problems
Slide40Coiling problems
The aneurysm may rupture with the angiographic manipulation
Secondly part of the coil could
embolise
out of the aneurysm into a more distal artery
The thrombus formation may extend out of the aneurysm and cause thrombus formation in the feeding vessels
Propofol
or
Thio
No vasodilators
Control
angiographically
Rarely done with IV sedation
Slide41Aneurysmal rupture
11% of patients with previously ruptured aneurysm (compared with an incidence of 1.2% in previously un ruptured aneurysms).
Maintain fluid and
BP ??
Clamp before and after the aneurysm
Slide42Reversal
The patient is not
extubated
until they are awake and breathing well
BP should be controlled with
Propofol or Narcotics infusionFurther agents to control BP (Beta blockers) during
extubation
might be used if infusions are found unsatisfactory
Slide43Post op problems
Neuro
deficits – new
Then do
CT scan
If normal Do angio
for vasospasm
Vasospasm
Rebleeds
Infarction
Fluid status
Urine output
Hyponatremia
Summary Worst headache (
neuro
, vasospasm,
rebleeds
) Incidence ( impending doom!!) Hunt, Fischer WFNS
Ecto and endo
Pre op – CNS, general, investigations
Induction – maintenance - recovery
Post op monitoring
Slide45Thank you all