Neuro Flashcards
SIADH vs. CSWS
SIADH
- normovlemic
- oliguria
- Urine Na 50-100
- tx = fluid restriction, Na
CSWS
- hypovolemic
- polyuria
- Urine Na»_space;100
- tx = fluids, Na
Management of BP with intracranial mass
CPP MAP-ICP
BP elevated to maintain CP in the setting of inc ICP with the mass Treat the ICP - elevated head - drain CSF - mannitol or furosemide - hyperventilate
Considerations for sitting position
Contraindicated w/ intracardiac shunts VAE hypotention Airway obstruction, poor access to airway quadriplegia from neck flexion Cerebral ischemia
Better exposure
Less tissues damage, retractions, bleeding, cranial nerve damage
Tx of VAE
Call for help 100% O2 Surgeon flood field with saline Bone wax on edges Compress jugular veins Aspirate air from CVC
BP management with aneurysm clipping
Deliberate hypotension reduced trans mural pressure and reduce risk of aneurysm rupture but given chronic HTN, CAD might place at unacceptable risk of cerebral and cardiac ischemia.
Discuss temporary clip with surgeon
Management with temporary aneurysm clip
MAP higher than normal to support collateral blood flow
Propofol to reduce CRMO2
Use EEG and SSEP
Brain relaxation with CSF drainage, mannitol to reduce traction needed
Effects of mild hypothermia for brain protection
Dec CRMO2
Delayed emergence Slow metabolism Inc infection In O2 consumption Myocardial ischemia Arrhythmias Coagulation defects
ST changes during crani, what is going on? What would you do?
SAH?
Aneurysm likely bleeding —> apply clips, lower BP slightly to help with repair and give propofol for neuro protection understanding risk of end-organ ischemia
Massive hemorrhage — compress carotids, avoid hypotension and resuscitate
Or myocardial ischemia
How do you clear a c-spine?
- Absence of cervical pain or tenderness
- Absence of paraesthesia or neurological deficits
- Normal mental status
- No other distracting pain
- Age >4
If not pass above then lateral C1-T1, open mouth ondontoid and A/P
Urine SG <1.005, inc serum Na, large volume urine, Osm <200
DI
Replace urinary losses with D5 1/2 NS
If exceeds 350ml/hr —> DDAVP (replaces patients ADH)
Significant hypotension 4 days post pituitary tumor removal, what is the cause?
Adrenal insufficiency from panhypopiuitarism
What is the normal CPP and what is the ideal CPP with a TBI?
Normal 80-100mmHg
Unknown for TBI
>70 may inc risk of ARDS
50-60 –> ischemia
so ideal may be 60-70
Would you hyperventilate a patient with head trauma?
Mildly only to 25-30 if other means were not successful and the ICP was high enough to risk brainstem herniation
Dec blood flow following trauma –> at risk for ischemia
Would you use N2O in TBI?
No
If cerebral perfusion were compromised i would want 100% O2
If hyperemia were an issue, N2O can potentially inc CBF
If air were trapped in the cranium –> expand further inc ICP
Criteria for Fat embolism syndrome
1 major + 4 minor
Petechial rash, hypoxemia, CNS depression or pulmonary edema
Tachycardia, pyrexia, retinal fat emboli, fat microglobulinemia, unexplained anemia
Extubation plan following IC mass resection
If normal, awake and reassuring airway pre-op, reasonable to perform deep extubation to avoid coughing and allow neuro exam
If obtunded pre-op - risk for aspiration, CO2 retention I would delay extubation. Possible to have post-op edema or hematoma –> dec neuro status and prolonged intubation
Risk factors for peripheral nerve injury
Male LOS >14 days Intra-op hypotension Hx vascular disease, DM Smoking Very thin or very obese
When might you avoid using mannitol to lower ICP
Disrupted BBB (preeclampsia, trauma)
Intracranial hemorrhage
–> worsen cerebral edema
*Normal ICP <15mmHg
Concerns with acute C-spine injury
- Resp function - esp if C3-5
- Hypotension - loss of sympathetic tone (T1-4)
- Aspiration - paralytic ileus
- Worsening SC injury - inadequate stabilization, hypotension, hypoxia, anemia
- Difficult airway - careful fiberoptic intubation
- Thermal regulation loss of vasoconstriction and temp sensation
- Autonomic dysfunction/hyperreflexia and arrthymia
Use of steroids in SC injury
Controversial - maybe some benefit within 8 hours but weigh risks of side effects like sepsis, hyperglycemia, pneumonia
Difference b/w spina bifida occulta and cystica?
Occulta = incomplete/abnormal formatio of midline structure w/o herniation of meninges
Cystica = failed fusion of neural arch, herniation of meninges +/- neural elements
Both have have underlying thethered cord or neuro deficits
Abruption/trauma w/ difficult airway and dec FHR, what will you do?
- Optimize mothers condition and prepare for emergency C/S
- Apply O2, auscultate for PTX
- Eval EKG
- LUD
- Call for surgeon to obtain surgical airway have area prepped
- Difficult airway equipment
- Secure airway awake
- Avoid ketamine (inc ICP, inc uterine tone, dec placental perfusion)
- Get labs (ABG, H&H, coags, lytes)
What are the monitoring options for CEA?
Awake - gold standard, requires cooperation, limited access to airway
TCD - non-invasive, can continue post-op, operator dependent, placed very near surgical site
Stump Pressure - >60 ideally
EEG - non-invasive, only reflects cortical structures, requires skilled interpretation
SSEPs - useful with abnormal EEG baseline, requires skilled interpretation
Would you give mannitol to a patient with AMS with new Cushing response?
It could potentially reduce ICP BUT it may worsen cerebral edema if BBB is not intact (trauma, Pre-E)
IC bleeding –> expansion of hematoma = avoid until intracranial pathology was clearly defined.
When would cardiac revascularization be indicated prior to CEA?
Risk benefit with vascular surgeon and cardiologist. When CABG or PCI may improve neurological and cardiac outcome in patient with severe cardiac disease., especially if they would benefit even is CEA were not planned.
Which anesthetic technique for CEA is best?
No evidence that either GA or regional is better
How would you monitor neurologic function during CEA?
If the surgeon utilized carotid shunting, i would use some form of monitoring to aid in determining whether patient required a shunt.
EEG SSEPs TCDs Stump pressure Cerebral oximetry
None of the current techniques are completely reliable and without limitation.
Best = awake patient –> consciousness, speech, C/L handgrip
As you raise the patients BP following slowing on EEG, you notice new onset ST depression. What would you do? Would you give NTG?
I would optimize myocardial O2 supply and demand
- 100% O2
- correct anemia
- treat tachycardia
- then if necessary carefully red SVR to treat ST depression while providing adequate cerebral perfusion
NTG may be a good choice for vasodilation, short duration and beneficial effects of coronary circulation
How would you intubate MVA patient with c-spine injury, SC compression, DM, HTN, etOH abuse?
Goals are to secure the airway avoiding further C-spine injury and aspiration
- aspiration ppx
- topicalize airway
- In-line stabilization
- Awake FOI
- Neuro assessment
What is PION?
Syndrome of post-op vision loss ranging from dec acuity to complete blindness - dec O2 delivery to part of optic nerve
First 24-48 hrs
Painless
Afferent pupillary defect, visual field defects, lack of light perception, optic disc normal
Who is at risk for developing PION?
Prolonged procedures (>6.5hrs) Substantial blood loss
How can you reduce the risk of vision loss?
Avoid/limit anemia, hypotension, hypovolemia hypoxia, external ocular pressure, prone head down, prolonged surgery, massive fluid rescusication, consider staging procedure
What are your concerns with MS?
Avoid spinal Epidural or block ok Sux = relative contraindication Avoid hyperthermia Autonomic dysfunction, exaggerated effect with sympathomimetics Sensitive to ND-NMBDs Relapse risk inc post-op and post-partum
Concerns with Myasthenia
Resistant to sux
Sensitive to ND-NMBDs
Severity, ocular to resp failure
Tx = pyridostigmine
Cholinergic crisis - weakness, salivation, bradycardia
Tensilon test - edrophonium inc strength = MG
- worsen = cholinergic crisis = give atropine
Risk factors for post-op ventilators support following thymectomy
> 6 years duration
Vital capacity <2.9L or <40ml/kg
Pyridostigmine dose >750mg
Co-existing resp disease
Concerns with Guillan-Barre
Spinal exacerbate symptoms
Epidural ok
Dysautonomia —> hypotension
Resp failure
No Sux
Tx = IVIG (even in pregnancy)
What are the advantages of furosemide over mannitol in reducing ICP
Does not inc CBF or ICP
Can be used in CHF and renal patients
Can be used when BBB has been compromised (trauma, pre-e, SAH)
What are normal values for cerebral blood flow?
50ml/100g/min
What are the determinants of cerebral blood flow?
- PaCO2 - 1ml/100mg per 1mmhg change
- PAO2 - dec to 50mmhg needed for sig increase in CBF
- Neurogenic control
- Temp
Midway through TURP, patient become confused and tachycardic. Stat Na returns at 120. Will you administer hypertonic saline?
No
Correction must be gradual to avoid central pontine myolinolysis
Start by restricting fluids, furosemide, monitoring EKG
Further deterioration –> consider 3%
Speed = 4-6 –> 6-12mmol/L/day first 24 hours
What are you concerns with the acromegalic patient?
DI
- glottic stenosis
CAD
HTN
OSA
Insulin resistance
Why is air embolism risk greater with cranial operations than other surgical sites?
There is greater gravitational gradient –> more air entry
How would you differentiate osmotic diuresis from over hydration?
Osmotic
- Osm >300
- SG >1.010
Overhydration
- Osm low
- SG <1.010 (like DI)
