spine surgery

Question 1

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

Answer 1

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

Question 2

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

Answer 2

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

Question 3

What changes if someone stops smoking for 8 weeks before surgery

Answer 3

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

Question 4

What are SSEPs?

Answer 4

• 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

Question 5

what are MEPs

Answer 5

• 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

Question 6

What is autonomic neuropathy?

Answer 6

• 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

Question 7

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

Answer 7

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

perform wakeup test

Question 8

what is posterior ischemic optic neuropathy (PION)?

Answer 8

• 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

Question 9

what is anterior ischemic optic neuropathy (AION)?

Answer 9

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

Question 10

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

Answer 10

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

Question 11

what are complications of deep cervical plexus block

Answer 11

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

Question 12

what are options for neurologic monitoring during CEA?

Answer 12

• 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)

Question 13

what is myocardial preconditioning?

Answer 13

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

Question 14

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

Answer 14

• 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

Question 15

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

Answer 15

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

Question 16

what are your concerns with acute cervical spinal cord injury?

Answer 16

• 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

Question 17

what is spinal shock

Answer 17

• 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

Question 18

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

Answer 18

• 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.

Question 19

what is autonomic hyperrelfexia?

Answer 19

• 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.