26. Anesthesia for Neurosurgery

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26. Anesthesia for
Neurosurgery

• ???????
• R1 ???

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INTRACRANIAL HYPERTENSION (1)

• ?? ICP? 15mmHg???? ?? ??? ??
• ?? ? expanding tissue or fluid mass
•            ? depressed skull fracture
•             ? CSF? ?? ??
•             ? brain edema? ???? systemic
  disturbance
• ?? headache, nausea, vomiting, papilledema,
  focal neurological deficits,
• altered consciousness
• Cushing response periodic increases in arterial
  BP with reflex slowing of the HR, abrupt
  increases in ICP lasting 115min.
• CEREBRAL EDEMA
• ?? brain water content? ??
• ?? BBB? ??(vasogenic edema) ? m/c
• ?? 1) Vasogenic edema mechanical trauma,
  inflammatory lesion,

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INTRACRANIAL HYPERTENSION (2)

• TREATMENT 
•   - underlying cause? ??
•     - vasogenic edema  corticosteroids BBB
  repair ??
•     - fluid restriction, osmotic agents, loop
  diuretics
•     - moderate hyperventilation(PaCO2 30-33mmHg)
  CBF?? ICP ???
•      
•   1)Mannitol
•      - dose 0.25-0.5g/kg
•      - effect ??? ICP??
•      - disadventage transient increase
  intravascular volume
• ??, ?? ?????  pul.
  edema?? ??
•      - ?? cranium? ???? Aneurysms, AVM,
  intracranial Hemorrhage
•  
• 2)Loop diuretics(furosemide)
•     - ? ????? 30? ?? ??? ???? ????? CSF?? ????
  ??
•      - mannitol? ?? ??? synergy effect

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ANESTHESIA CRANIOTOMY FOR PATIENTS WITH MASS
LESIONS(1)

• Intracranial mass ? congenital ? neoplastic ?
  infectious ? vascular
• ??? ???? mass? growth rate, location, ICP ?? ??,
  ??? ???
• Common sx headache, seizures, a general decline
  in cognitive or specific
• neurological function ,
  focal neurological deficits
• PREOPERATIVE MANAGEMENT
• preanesthetic evaluation Intracranial HTN ??
• Neurologic assessment mental status, any
  existing sensory or motor deficits
• medication corticosteroid, diuretic,
  anticonvulsant therapy
• laboratory evaluation   steroid-induced
  hyperglycemia
•                              electrolyte
  disturbance by diuretics or ADH
•                             
  anticonvulsant level
•  Premedication
• normal ICP benzodiazepine

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ANESTHESIA CRANIOTOMY FOR PATIENTS WITH MASS
LESIONS(2)

• INTRAOPERATIVE MANAGEMENT
•   
• Monitoring
•     1) standard monitoring  
• 2) direct intraarterial pr. monitoring  -
  arterial blood gas measure PaCO2, ETCO2
•     3) bladder catheterization (? diuretics?? )
•     4) central venous access pressure
  monitoring - vasoactive drug ??? ??
•     5) visual evoked potential -  pituitary tumor
  resection? optic n. damage ?? ??
•     6) ICP monitoring intracranial HTN?
  perioperatively
• Induction
• anesthesia and intubation the trachea - SLOW
  ICP? ??? CBF?? ??
• ????? ??? HTN -gt ICP ?? -gtCPP??, herniation??? ??
  
• BP? ??? ?? -gt CPP?? 
• m/c induction technique ? thiopental or propofol
  together with hyperventilation
•           ? NMBAs
  ventilation????, ?? ??, ??? ??

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ANESTHESIA CRANIOTOMY FOR PATIENTS WITH MASS
LESIONS(3)

•  
• Positioning
• Frontal, temporal, parietooccipital craniotomies
  supine position
• head elevation 15-30? (? venous drainage and
  CSF drainage ??)
• Positioning? Tube disconnection ??
•  Maintenance of Anesthesia
• Nitrous oxide - opioid - NMBA technique ? ??
• HTN??? low- dose (1ltMAC) ????? ?? ??
• opioid low dose inhalation agents  or total
  IV technique
• continued hyperventilation PaCO2 30-35mmHg
• avoid - PEEP High mean airway pr (low rate and
  large tidal vol.) (? CVP??)
• fluid - glucose-free isotonic crystalloid(ex.
  N/S) or colloid solution
•              hyperglycemia-gt ischemic brain
  damage??
• Colloid solution restore intravascular vol.
  deficits
• Isotonic crystalloid solution maintenance fluid
  requirements

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ANESTHESIA FOR SURGERY IN THE POSTERIOR FOSSA(1)

• Obstructive Hydrocephalus
• infratentorially located mass obstruct flow of
  CSF increase ICP
• ? ICP? ????? ?? ?????? ????? ventriculostomy
  
• Brain Stem Injury
• posterior fossa operation cranial nerve injury
• 
  circulatory and respiratory brain stem center??
• Damage to respiratory center circulatory
  change? ?? ???.
• ex.) abrupt change in BP, HR, cardiac
  rhythm
• ? ?? ??? surgeon?? ??? ????
• ????? abnormal respiratory pattern or inability
  to maintain a patent airway following extubation
  ? brain stem injury ??
• Brain stem auditory evoked potentials - useful
• Positioning
• Modified lateral, prone, sitting position
  (preferred)
• position? ???? head? ?? ????? ????
• Careful positioning avoid injuries

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ANESTHESIA FOR SURGERY IN THE POSTERIOR FOSSA(2)

• Pneumocephalus
• sitting position -  pneumocephalus ?
• CSF? ??? ????? air?
  subarachnoid space? ?? ???
• Dural closeure? pneumocephalus? ?? ? compress the
  brain
• Postoperative pneumocephalus delayed awakening
• 
  impairment of neurological function
• Venous Air Embolism (1)
• wound? heart level?? ????? ?? position??? ?? ? ??
• sitting craniotomy? ?? ???? ?? (20-40)
• Physiological consequences depend on
• vol. and rate of air entry , patent
  foramen ovale ( paradoxical air embolism )
• Air bubble ? venous sys. ? pul. Circulation
  (diffuse into the alveoli )
• Pul. Clearence ??? ??? ????
• pul. a. pr.?? ? Rt. ventriclular afterload
  ? ? cardiac output ?
• N2O air ? volume ? (?? ?? air?? ? ??)
• Sign hemodynamic change?? ETCO2? saturation? ??

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ANESTHESIA FOR SURGERY IN THE POSTERIOR FOSSA(3)

• Venous Air Embolism (2)
•     
• A. Central Venous Catheterization
•   allow aspiration of entrained air
•        catheter? ??? ??? ??? ?????? ?? ??
•        ?? confirm TEE or intravascular
  electrocardiography(biphasic P wave)
•           
•  B. Monitoring For Venous Air Embolism
•  most sensitive intraop. Monitor TEE and
  precordial Doppler sonography
•        ETCO2 ? pul. a. pr. ? ?? less sensitive
  but clinical sign? ????? ????
• sx. sudden decrease in ETCO2 ( pul. Dead
  space ? )
• mean pulmonary artery pressure ?
• change in BP, Heart sound late
  manifestation

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ANESTHESIA FOR SURGERY IN THE POSTERIOR FOSSA(4)

• Venous Air Embolism (3)
• C.Treatment Of Venous Air Embolism
•  1. surgeon?? notify surgical field?
  saline?? ??? ??? skull edge
• ? ?????? bone wax? ??? ( entery
  site????)
•      2. N2O ??, 100O2
•      3. CVP Cath.? aspirated
•      4. volume infusion -gt CVP?? ???
•      5 .vasopressor?? (hypotension? ??)
•      6. Bilateral jugular vein compression
  (cranial venous pr.?????)
• - air ????? ??? ??
•      7. PEEP(CVP?? ??)
•      8. Head down position wound closed quickly
•      9. cardiac arrest???, advanced cardiac life
  support algorithms ??

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ANESTHESIA FOR STREOTACTIC SURGERY

• Indication invountary movement disorders
• intractable pain
• epilepsy
• diagnosing and treating
  tumor- located deep within the brain
• ??? local anesthesia???? ??
• sedation ? amnesia ? ????? propofol? ????? ?
• Stereotactic head frame ? ?? ?? ???? ?? ???
  intubation? awake intubation with a fiberoptic
  bronchoscope!

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ANESTHESIA FOR HEAD TRAUMA(1)

•  Significance of a head injury
• 1) Irreversible neuronal damage??
•    2) 2??? ???
•       (1) hypoxemia? hypercapnia?? ???
  ??      
•       (2) epidural,subdural,intracerebral
  hematoma ? ????? ??
•       (3) intracranial HTN ???
•     --gt surgical anesthetic management ?
  ??? 2??? ??? ?????
• ??????? ??
•    Glasgow Coma Scale (GCS) score
• severity of injury and outcome ? ??
• ( ex. GCS score lt 8 ? ? 35 mortality
  )
•    

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ANESTHESIA FOR HEAD TRAUMA(1)
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ANESTHESIA FOR HEAD TRAUMA(2)

• PREOPERATIVE MANAGEMENT(1)
• Patency of the airway, adequacy of ventilation
  oxygenation, correction of
• systemic hypotension ? ????? ????? ?
• Airway Obx and hypoventilation? ?? ???
• Pul. contusion, fat emboli, or neurogenic
  pul.edema ?? complication?
• ?? 70?? hypoxemia ? ??? ???.   
• ??? hypoventilation, absent gag reflex, or GCS???
  8??????
•           -gt Tracheal intubation and
  hyperventilation
•      Intubation
• ?? ??? full stomach??? ??
• mask? ??? preoxygenation and hyperventilation

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ANESTHESIA FOR HEAD TRAUMA(3)

• Hypotension   
• Head trauma ???? hypotension ?? ?? injury? ??
  ?? ???? ??.
• spinal cord injury ? spinal shock? ???
  sympathectomy? ?? ???
• Hypotension ??
•         -  by colloid solution and blood (brain
  edema?? ??)
•         -  severe???? vasopressor??
• glucose-containing or hypotonic solution? ???
• Hct gt30??
• invasive monitoring intraarterial pr. , central
  venous or pul. a. pr, ICP...

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ANESTHESIA FOR HEAD TRAUMA(4)

• INTRAOPERATIVE MANAGEMENT
• other mass lesion? ??
• barbiturate-opioid-nitrous oxide-NMBA technique?
  ?? ????
• PaCO2 lt30 ? hyperventilation? ??? (CBF? ?? ???
  ??)
• HTN with tachycardia ? b- blocker? ???
• Excessive vagal tone - atropine or
  glycopyrrolate??
• DIC ,ARDS, pulmonary aspiration, neurogenic pul.
  edema, G-I hemorrhage, Diabetic Insipidus?? ?? ??
  ?? 

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ANESTHESIA CRANIOTOMY FOR INTRACRANIAL
ANEURYSMS ARTERIOVENOUS MALFORMATION(1)

• CEREBRAL ANEURYSMS(1)
• Preoperative Consideration
• rupture of a saccular aneurysms m/c cause of
  subarachnoid hemorrhage
• acute mortality following rupture 10
• survivors 25 subsequently die within 3 months
  from delayed cx.
• ???? 50 ?? left with significant neurological
  deficits
• prevention of rupture
•  gt 7mm surgical Ix
• Unruptured Aneurysms
• m/c sx Headache
• m/c sign 3rd nerve palsy
• Others brain stem dysfunction, visual field
  defects, trigeminal neuralgia, 
• cavernous sinus syndrome,
  seizure, hypothalamic-pituitary dysfunction
• Dx angiography, MRI angiography, helical CT
  angiography

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ANESTHESIA CRANIOTOMY FOR INTRACRANIAL
ANEURYSMS ARTERIOVENOUS MALFORMATION(2)

• Ruptured Aneurysms
• usually acute subarachnoid hemorrhage
• less commonly epidural space or brain hemorrhage
• Sx. focal neurological deficits?? sudden severe
  headache
•           often associated with nausea,
  vomiting
•            transient loss of consciousness ( ?
  ???? ICP??? CPP? ??)
• Delayed Cx cerebral vasospasm (30) ,
  rerupture, hydrocephalus
• symptomatic vasospasm Tx triple H therapy
  hypervolemia, hemodilution, HTN
• neurosurgical management rebleeding? vasospasm?
  risk? ?? ???.
• rerupture 1030
• early surgical obliteration of the aneurysm
  recommended for stable patient

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ANESTHESIA CRANIOTOMY FOR INTRACRANIAL
ANEURYSMS ARTERIOVENOUS MALFORMATION(3)

• PREOPERATIVE MANAGEMENT
• Preanesthetic evaluation determine whether
  rupture has occurred
• Neurological findings? coexisting disease??
• controlled hypotension? relative contraindication
  
•      preexisting HTN and renal, cardiac or
  ischemic cerebrovascular disease
• EKG Abn. - commonly seen in subarachnoid
  hemorrhage (not heart dis.)
• Persistent elevation in ICP little or no
  premedication to avoid hypercapnia
• INTRAOPERATIVE MANAGEMENT(1)
• rupture or rebleeding? ??? ?? ???? blood? ??
• anesthetic Mx focus preventing rupture or
  rebleeding
•                            
  cerebral ischemia or vasospasm ??? ??? ????
•  intubation?? ??? ?? ??? ?????? ???
•  intraarterial and central venous(or pulmonary
  artery) pressure monitoring
•  BP? ??? ?? ?? ??
•  mannitol dura is opened ( to facilitate
  surgical exposure reduce tissue trauma)

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ANESTHESIA CRANIOTOMY FOR INTRACRANIAL
ANEURYSMS ARTERIOVENOUS MALFORMATION(5)

• INTRAOPERATIVE MANAGEMENT(2)
• controlled hypotension is useful
•       (1) decrease transmural tension across
  the aneurysm
•        (2) rupture??? ??? surgical clipping????
  ??
•        (3) blood loss??
•       (4) bleeding? ???? ??
• head-up position ? volatile anesthesia(Iso.)? ???
  ??? ??? ??
• thiopental? mild hypothermia protect Brain
• neurological condition? ?? extubation?? ??
• Rapid awakening ICU ?? ? OR?? neurological
  evaluation???? ??

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ANESTHESIA FOR SURGERY ON THE SPINE(1)

• PREOPERATIVE MANAGEMENT
• Any existing ventilatory impairment and airway??
• anatomic abn. and limited neck movement
• neurological deficits ??
• Patients with Degenerative dis. pain ?  opioid
  with premedication
• ???, difficult airways or ventilatory impairment
  premedication ?????
• INTRAOPERATIVE MANAGEMENT(1)
• Positioning
• ??? prone position
•        corneal abrasion or retinal ischemia 
  ??  
•         nose, ear, forehead, chin, breast(female)
  or genitalia(male)?? ???? ??
•         arm - comfortable position or extended
  with elbow flexed   
• supine position ant. approach to cervical spine
  
• ass. with injuries to the trachea,
  esophagus, recurrent laryngeal n.
• sympathetic chain, carotid a. or jugular
  vein
• ??? sitting and lateral decubitus position

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ANESTHESIA FOR SURGERY ON THE SPINE(2)

• INTRAOPERATIVE MANAGEMENT(2)
• Monitoring 
• Intraarterial possibly central venous pr.
  Monitoring positioning or turning?? ??
• ( significant blood loss? ??????
  preexisting cardiac dis. ???)
• Elective hypotension or weak epinephrine
  infiltration of the wound
• - intraoperative blood loss ?
• somatosensory evoked potentials and motor evoked
  potentials ??
•    - detect intraoperatively spinal cord
  injury from excessive distraction