spine surgery Flashcards

1
Q

what are symptoms and timeline of alcohol withdraw in someone who presents for surgery?

A

tremors 6-8 hours
hallucinations 1-3days
> 3 days then life threatening delirium, confusion, agitation, autonomic instability (fever, tachy, HTN)

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2
Q

What anesthesia concerns do you have in someone with chronic alcohol abuse?

A
  • increased MAC
  • tolerance to drugs
  • cognitive impairment
  • cerebral atrophy
  • cerebral degeneration
  • peripheral neuropathy
  • cirrhosis
  • cardiomyopathy
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3
Q

What changes if someone stops smoking for 8 weeks before surgery

A
  • reduced carboxyhemoglobin
  • shifting oxyhemoglobin dissociation curve to the right
  • improved ciliary function
  • reduced nicotine levels
  • airway hyperreactivity
  • sputum production
  • peri-operative pulm complications
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4
Q

What are SSEPs?

A
  • somatosensory evoked potentials (SSEPs)
  • monitor ascending sensory neural pathways in POSTERIOR spinal cord
  • show decreased amp, increased latency with anesthetic suppression
  • indirect monitor of anterior spinal cord function

Significant change means 50% drop in amplitude and/or 10% increased latency

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5
Q

what are MEPs

A
  • motor evoked potentials (MEPs)
  • detect motor injury
  • detect descending motor pathways in the ANTERIOR spinal cord
  • require TIVA
  • MEPs more sensitive to gas (volatile agents) than SSEPs are

Significant change in MEP means 50% drop in amplitude

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6
Q

What is autonomic neuropathy?

A
  • neuropathy of CNS
  • S/S:
    gastroparesis
    GERD
    orthostasis
    painless MI
    HTN
    resting tachycardia
    exercise intolerance
    early satiety
    peripheral neuropathy
    dysrhythmias
    N/V
    RESISTANCE to INDIRECT acting agents like ephedrine

diabetic autonomic neuropathy often affects parasympathetic system first –> measure HR response to valsalva maneuver

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7
Q

What do you do if there’s a change in SSEP/MEP signals during spine case?

A
  • correct hypoxia, hypotension, hypovolemia, anemia,
  • check if too much anesthesia
  • ask surgeon to r/o surgical causes like retraction

perform wakeup test

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8
Q

what is posterior ischemic optic neuropathy (PION)?

A
  • most common cause of post-op vision loss
  • decreased O2 delivery to optic nerve –> nerve damage
  • presents within 1-2 days after surgery
  • PAINLESS vision loss, decreased pupillary response to light in affected eye
  • optic disc appears normal
  • risks: long surgery > 6.5hrs, EBL 45% EBV
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9
Q

what is anterior ischemic optic neuropathy (AION)?

A

a/w cardiac surgery
painless vision loss
fundoscopic exam findings include optic disc edema in AION

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10
Q

how do you do a superficial cervical plexus block? Deep cervical plexus block?

A

superficial: inject 10cc of LA along posterior border of SCM

Deep: draw a line from mastoid process to Chassaignac’s tuberacle at the level of cricoid cartilage
C2 transverse process palpated caudad to the mastoid process, put 10cc of LA at C2 - C4 transverse process

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11
Q

what are complications of deep cervical plexus block

A
epidural/ subarachnoid injection 
phrenic nerve blocked 
inject into vertebral artery 
RLN blockade
Horner's syndrome
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12
Q

what are options for neurologic monitoring during CEA?

A
  • if regional, talking to patient
  • stump pressure (pressures under 50 = hypo-perfusion)
  • EEG
  • SSEPs (measures response of sensory cortex to electrical impulses from peripheral sensory nerve stimulation)
  • TCD of middle CA, detect embolic events
  • cerebral ox
  • jugular venous oxygen sat
  • regional cerebral blood flow (IV carotid artery RA xenon injection)
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13
Q

what is myocardial preconditioning?

A

exposure to certain drugs protect the myocardium against MI and reperfusion injury

volatile agents do this even at a MAC of 0.25
involves opening K-ATP channels, prevent mitochondrial Ca2+ overload

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14
Q

during a CEA, HR drops to 48, BP drops to 88/40, what’s going on?

A
  • surgical manipulation of carotid body and sinus (ask him to stop or infiltrate area with LA to prevent swings)
  • myocardial depression
  • MI or cardiac ischemia
  • dysrhythmia
  • pre-existing autonomic neuropathy
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15
Q

spinal cord injury to what level affects the diaphragm? What about chest wall innervation?

A

diaphragm C3-5
chest wall innervation C6- C7 –> can cause paradoxical breathing and inability to cough effectively or clear secretions –> atelectasis and infection

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16
Q

what are your concerns with acute cervical spinal cord injury?

A
  • respiratory dysfunction
  • hypoT 2/2 loss of sympathetic tone below level of injury and loss of cardiac accelerators (T1 - T4)
  • pulm aspiration (GERD, paralytic ileus
  • difficulty intubating due to C-collar
17
Q

what is spinal shock

A
  • 2/2 acute spinal cord injury
  • flaccid paralysis
  • paralytic ileus
  • loss of sensation, spinal reflexes, sympathetic vasomotor tone, temp regulation below level of injury
  • if high, may lose diaphragmatic function
18
Q

when is it safe to use sux in spinal cord injury patient?

A
  • only use in first 24 - 48hrs after acute spinal cord injury
  • have the most hyperK after 1month to 5months after injury. Risk is less after 6months. Many recommend not using from 1 day to 1 year after injury.
19
Q

what is autonomic hyperrelfexia?

A
  • lesion above T7
  • cutaneous (pain) or visceral (bladder or rectal) distention stimulus below spinal cord injury results in sympathetic discharge.
  • unopposed sympathetic vasoconstriction below lesion
  • reflexive vasodilation above level of lesion. Reflex bradycardia from carotid sinus receptors.