Neuro Flashcards
What anesthesia would you give to pts with MS?
- Avoid Succ!
- May have resistance OR prolonged response to NDMR
- No IV or inhaled anesthetic is superior
*
What are you monitoring for in a pt with MS?
What should you consider with emergence?
- ANS dysfunction- lower threshold for arterial line
- Consider baseline muscle weakness during emergence; extubate wide awake with full NMB reversal
Would you use regional anesthesia for a pt with MS?
- Best to avoid; may be considered in OB
- spinal anesthetics have been associated with post-op exacerbations
- because of damage to nerves, regional anesthesia may cause injury, especially if directly applied as in Spinal
- epidural anesthetics and peripheral nerve blocks have no reports of exacerbations
Guillian barre expectations during surgery
- 60% have ANS dysfunction- pt does not compensate for physiological stressors normally
- will need positive pressure ventilation d/t muscle weakness
-
hypotension:
- positive pressure vent settings
- blood loss
- position change
-
hypertension:
- DVL
- pain
- with indirect acting vasopressors and sympathomimetics (fluids first)
- art line mandatory
- maintain preload with fluids
- altered temperature regulation
How would you muscle relax a pt with Guillian-Barre?
- Avoid succ!
- Use a NDMR with minimal CV effects (vecuronium)
- monitor carefully for increased sensitivity or resistnace
- avoid NDMR with histamine release
What should you consider regarding extubation for a pt with Guillian Barre?
- Monitor vigilantly because they are high risk for respiratory failure!
Would you use regional anesthesia for a pt with guillian Barre?
- Epidural opioids can be beneficial for pain and discomfort
- Regional can be used with caution
- pts are sensitive to LAs (because of the Na channel blocking factor?)
- Epidural with slower onset preferred to rapid bolus of spinal
What’s the deal with Levodopa in a pt with parkinson’s?
- Remember E1/2t is short
- withdrawal effects after 6 hours
- give levodopa 20 minutes before induction and repeat prn via OG tube and post op
- If oral dose cannot be given, apomorphine SQ is a dopamine agonist that can be given
What should you consider regarding GA for a Parkinson’s pt?
- Aspiration risk- because of salivation, dysphagia, esophageal dysfunction
- RSI
- Avoid dopamine antagonists
- butyrophenones (droperidol)
- phenothiazines
- metoclopramide
- (unless you are treating L-dopa CV SE at the vasal ganglie)
- Alfentanil and fentanyl reported to cause an acute dystonic reaction
What medications can you use for your GA for a pt with Parkinsons?
inhaled agents?
NMB?
- Ketamine can be used, but can be an issue because it causes SNS/psychosis and so can dopamine
- Plan for pt to be volume depleted; have aggressive fluid plan
-
Iso, Sevo, and Des acceptable
- may experience exaggerated BP decrease
- All types of muscle relaxant acceptable
Do you extubate a parkinson’s pt awake or deeply sedated?
Wide awake after full reversal criteria is met because they are likely to have respiratory complications
What drugs do you avoid during deep brain stimulation surgery?
What drugs are best?
- Avoid:
- L-dopa might be held in advance
- drugs that enhance GABA
- Best
- Opioids
- dexmedetomidine
- Avoid excessive sedation for neurologic assessment and airway management
- Communicate about any drug you are giving to the surgeon
How will you intubate a patient with a spinal cord injury?
What if they are awake and alert?
- DVL with in-line stabilization for emergency or unstable/uncertain C-spine stability
- If awake, alert, and cooperative:
- Awake fiberoptic intubation
- blind nasal intubation
- transillumination with lighted stylet
- LMA or Bullard laryngoscope
With what kind of spinal injuries would you expect more blood loss?
- Blood loss not large unless harvesting the iliac crest bone graft or vertebral body corpectomy
- Thoracic and lumbar regions have more blood loss than cervical
- expect hemodynamic instability from spinal shock
How would you expect to treat hemodynamic instability in a pt with a spinal cord injury?
- Art line required
- Elderly pts or those with significant hemodynamic lability may require PAC
- Treat with:
- aggressive fluids
- blood replacement
- continue pre-op vasopressors
- keep BP robust!
What drugs would you use for GA of a spinal cord injury?
-
All inhaled and IV agents acceptable
- N2O if closed air spaces have been ruled out
- NDMR- all acceptable
- Pancuronium SNS stimulation desireable
- Succinylcholine- OK for first few hours after injury but then should be avoided forever
What are some GA concerns for a pt with a chronic spinal cord injury?
- Renal failure common
- High DVT risk
- position carefully- increased risk for fracture/skin break down
- chronic pain common
- spacsticity in skeletal muscle, often treated with baclofen
- can cause sz if interrupted
What are some medication/anesthetic agent considerations to make regarding a pt with a chronic spinal cord injury?
- Surgery may cause AD even if they have never experienced it before
- VA, epidural or intrathecal anesthesia are effective in prevention
- have vasodilator available
- No Succ! >24 hours after injury
- use NDMR
- Pts should be monitored post op for AD
- can develop after anesthetic wears off
What dose of Nitroprusside would you administer for AD?
1-2 mcg/kg
Anesthetic considerations for pts with seizures
- Consider additive effect of anticonvulsants and sedative/anesthetic drugs (both use GABA)
- Consider how anti-epileptic meds may affect organs
- coagulation, CYP450 induction
- Give anticonvulsant meds morning of surgery, intra-op, and post op
What medications must you avoid when caring for a pt with seizures?
- Methohexital
- ketamine
- etomidate
- meperidine
- atracurium and Cisatracurium (Laudanosine)
- Enflurane
- Alfentanil
How will you notice an intraoperative seizure?
What will you do?
- BP and HR changes, maybe clonic movement depending on NMB
- IV TPL, propofol or benzos
- direct application of cold saline to the surface of brain
- ABG and temp monitoring
- adjust ventilation to blow off high CO2
What are the 5 determinants of CBF?
- PaCO2
- our bes option for affecting CBF, at least for 6 hrs
- PaO2
- the hail mary
- Arterial pressure, autoregulation- btween 50-150
- Venous pressure
- head position
- Anesthetic drugs and techniques
Describe the difference in CBF between a person with normal autoregulation and one without.
(graph)
What is the affect of volatile agents CBF?
- All volatile agents 0.6-1.0 MAC “uncouple” CMRO2 and cerebral blood flow
- vasodilation in the face of decreased metabolic need
- the greater the concentration, the more pronounced the uncoupling
- us IV agents (propofol) and hypocapnia to help compensate
- N2O has less interference with autoregulation compared with sevo/des/iso
- pt should have no recall with anything above 0.5 MAC
What is the affect of IV anesthetics on CBF and ICP?
What is the exception to the general rule?
- General rule: IV anesthetics are vasoconstrictors and will decrease CBF and ICP in general
- Ketamine is exception- DO NOT use in the face of inceased ICP
- Propofol and barbs are best
- Midaz, opioids and etomidate OK
- watch for resp. depression
What are the important principles about managing the anesthetic of a patient with increased ICP?
- Reduce ICP
- posture, hyperventilation, CSF drainage, hyperosmotics, Diuresis, Corticosteroids, barbs
- reduce CMRO2
- premedication
- smooth induction, maintenance, and emergence
- Venous air embolism detection
What are some ways to achieve a smooth emergence?
- Give large bolus of opioids at beginning of surgery
- pre inject lidocaine directly onto vocal cords (LTA)
How will you care for patients with intracranial tumors?
monitors, etc
non anesthetic medications/fluids
- Monitors/IV
- 2 large bore IV- expect lots of bleeding
- PRBC available
- Use Normasol or plasmalite (if unavailable, alternate LR and NS)
- Standard monitors
- Art line, temp, and PNS mandatory
- zero the art line at the circle of Willis
- Consider CVP or PA- depending on pt baseline status
- Meds- careful with sedative pre-medication
- corticosteroids!
How would you induce a pt with an intracranial tumor?
- Goal is to blunt the hemodynamic changes caused by DVL
- Optimize ICP pre-induction with osmotherapy, etc
- pre oxygenate pt fully
- TPL or propofol- deep!
- opioid
- NDMR
- Lidocaine
- consider extra TPL after twitch response disappears and before intubation
- esmolol infusions are also recommended for HR and BP control
What are the dosed you would give during induction of pts with intracranial tumors?
TPL
propofol
fentanyl
lidocaine
- TPL: 3-5 mg.kg
- Propofol: 1.25-2.5 mg/kg
- Fentanyl: 3-5 mcg/kg
- Lidocaine 1.5 mg/kg
What should you consider during maintenance of a pt with an intracranial tumor?
- Ventilation controlled PaCO2 between 30-35 mmHg
- Consider baseline intracranial compliance when determining how much VA to use
- 0.6-1.0 MAC
- if low compliance consider TIVA + low dose iso for amnesia
- Avoid pt movement
Why is it important to have a smooth emergence for a pt with an intracranial tumor?
How can this be done?
- Bucking can cause HTN and ICP elevation = cerebral edema and hemorrhage
- No reversal until head dressing applied
- IV lidocaine 1.5 mg/kg
- antihypertensives
- extubate when fully reversed and responsive
- leave ETT in place until following commands
- HOV 30 degrees
- warm pt to comfortable temp to avoid shivering
Which procedures have higher risk of Venous air embolism?
- posterior fossa
- upper c-spine procedures
- supratentorial procedures
- parasagittal or meningiomas near sagittal sinus, craniosynestosis
Describe the Venous air embolism monitoring chart
How are acute VAEs managed?
- Prevent further air entry
- notify surgeon- flood or pack surgical field
- jugular compression
- lower head
- Treat intravascular air
- aspirate via right heart catheter
- discontinue N2O
- FiO2 100%
- turn lateral with right side up
- pressors/inotropes/CPR
How should you manage the anesthesia for Head trauma?
BP
ventilation
fluids
- Maintain CPP 50-70 mmHg
- Hyperventilation
- used for acute ICP management
- Fluids to maintain intravascular volume
- prevent reduced serum osmolarity (NS, Normosol/plasmalyte, 5% albumin, blood all better than LR)
- avoid dextrose (keep glucose <180)
What monitors are needed for pts with head trauma?
- Standard
- Art line- pre induction is best, but do not delay an emergency craniotomy for a line placement
- +/- R heart catheter (manage hemodynamics and VAE risk)
How should you induce a pt with head trauma?
- lidocaine 1-1.5 mg/kg
- IV anesthetics EXCEPT Ketamine
- consider hemodynamic stability needs
- opioids are a good choice
- NDMR- avoid histamine, avoid Succ if non-emergent
- succ will increase ICP
How should you emerge a patient with head trauma?
- transport intubated to ICU because max swelling is 12-72 hours post injury
- avoid HTN, coughing
- labetalol, esmolol, TPL or propofol helpful
What do you need to ask of a pt with a history of CVA?
- How long ago?
- any deficits?
- increased risk of adverse outcomes within first 9 months of CVA
- What meds do they take?
- BP, anti-thrombotic, anticoagulant, anti-platelet
What anesthetic technique is contraindicated in pts who have had a CVA?
PNS?
- neuraxial in para/hemiplegia or active anticoagulant use
- Do not monitor neuromuscular blockade on affected extremity
What are the important aspects of BP management in a pt who has had an intracranial aneurysm or sub arachnoid hemorrhage?
What is the major complication?
- Acute hypertension causes risk of rerupture which is often FATAL
- Brain relaxation will help make surgery easier
- mannitol or hyperventilate
- High-normal MAP to prevent critical reduction of CBF to ischemic area
- tight control of MAP as the surgeon clips the aneurysm and/or controls bleeding
- major intraoperative complication is hemorrhage, rebleeding kills!
How would you monitor a pt with intracranial aneurism/ SAH?
- Art line pre-induction
- +/- CVP, depending on amt of mannitol, fluid replacement, vasospasm
- +/- EEG or SSEP/MEP
How would you induce a pt with Intracranial aneurysm or SAH?
- Smooth induction CRITICAL
- prevent hypertension and hypotension and maintain good ICP control
- lidocaine + esmolol/labetalol + opioids + high dose TPL or propofol
If your pt with an intracranial aneurysm or SAH has a high ICP, what would you use for their maintenance anesthesia?
- propofol gtt- 100-300 mcg/kg/hr after bolus
- Fentanyl- 1-4 mcg/kg/hr
- <10 mcg/kg if extubation planned
- 0.5 MAC Iso and O2
- All of the above meds together
How long can a clamp remain on the parent artey that supplies the aneurism?
<10 minutes
How should you administer fluids to a pt with intracranial hemorrhage and SAH?
- prior to clipping, only administer maintenance and deficit
- PRBC should be immediately available
- after clipping, CVP can increase to 10-12 mmHg
How should you plan to emerge a pt with intracranial aneurism or SAH?
- avoid coughing, straining, hypercarbia, and HTN
- grade 1-2 with no intra-op complications can be extubated in OR
- Grades 3-5 or intraop complications should remain intubated on mechanical ventilation
What are important post op considerations for the pt with intracranial aneurysms or SAH?
- control HTN to avoid cerebral edema and hematoma
- control pain
- avoid increased PaCO2
- antihypertensive drugs
- vasospasm remains a threat
- high-normal intravascular volume, avoid hypotension
