Neuro Flashcards
Depolarization of nerve is due to the … of Na … the cell
However depolarization of SA node is due to the entry of … into pacemaker cell
Entry of Na into cell
Ca
The concentration of Cl, Mg, and PCO2 is higher/lower in CSF compared to the plasma concentration?
Higher
During ECT treatment there is initial parasympathetic stimulation followed by sympathetic stimulation. Initial arrhythmias is … followed by ….
Bradycardia then tachycardia
The purpose of using succinylcholine during ECT treatment is to ….
Avoid fractures during seizure activity
Drugs increases seizure duration of ECT?
Etomidate, Caffeine, Aminophylline
Drugs decreases seizures duration of ECT duration?
Thiopental, propofol, midazam, lidocaine, diltiazem, esmolol
I’m a patient with failed prior ECT treatment, due to shorter seizure duration, …. should be used
Etomidate
Propfol and thiopental effect on seizure
Decreases its duration and increases threshold
Ketamine and lidocaine effect on seizure duration
Decreases its duration
Etomidate effect on seizure
Prolongs it’s duration
Absolute CI for ECT
Pheochromocytoma
Relative CI for ECT
Pregnancy
Cardiac conduction defects
Aortic and cerebral aneurysm
Recent CVA
Is AICD CI for ECT?
No. It should be deactivated prior to ECT and interrogation done after ECT ttx
Most sensitive evoked potential to anesthetic
VEP
VEP > MEP > SSEP > BAEP
Most resistance evoked potential to anesthetic
Brain stem Auditory evoked potential
BAEP
Thiopental + propofol + isoflurane effect on SSEP amplitude…. and it …. SSEP latency
They decrease amplitude and increase latency
…. unique in increasing both amplitude and latency of the SSEP
Etomidate
Ketamine and N2O increases or decreases SSEP amplitude and it latency
Both effect amplitude only.
Ketamine increases it
N2O decreases it
Persistent vegetative state vs coma?
If ptn can be partially aroused -> vegetative
Cannot aroused with painful stimuli, light/sound -> coma
Brain death causes absent cortical and brain stem function, however … are active
Spinal reflexes
Choice of treating bradycardia in brain dead ptn?
Direct acting drugs (isoproterenol, epi). And pacing
The indirect (atropine) ineffective
Most common abnormality in brain dead patients?
HyperNa from DI
EEG waves of awake? Relax state? And sleep?
Beta -> awake
Alpha -> relaxed
Theta -> sleep and anesthesia
Delta -> Deep anesthesia
Burst suppression on EEG waves is the goal of …. administration and overdose of those meds will causes … on EEG
Barbiturates/ propfol
Avoid the electrical silence EEG
Signs of cerebral ischemia on EEG
Slowing waves (theta and delta) Changes in spectral edge Burst suppression Loss of evoked potentials Isoelectric EEG
What dose slowing of spectral edge frequency on EEG hints for?
Cerebral ischemia
Deepening anesthesia
Spike and dome activity on EEG?
Epileptic activity
So N2O increases CMRO2 which leads to increase CBF and propfol/thiopental dose the opposite. What about isoflurane?
decreases CMRO2 but increases CBF
Decreases PaO2 has no effect on CBF until it reaches …. below this level CBF increases
60 mmHg below this a steep increase in CBF
PaCO2 curve become flat below …. and above …. on CBF/pressure curve.
In between an increase in each PaCO2 causes increase CBF by …/100gm of the brain tissue
Below 25 mmHg and above 100 mmHg a flat line
1 mmHg PaCO2 increase causes increase of 1mL/100 g of brain tissue (2% increase)
Normal CBF …/100gm of brain tissue
…% of CO
… mL per minute
50 mL
15%
750 mL
CMRO2 is ~ …/ 100gm of brain tissue
3-4 mL
The organ that consumes highest amount of O2 per fm:tissue is ….
Myocardium
… has the highest blood flow per gm of the tissue
Carotid body
…. circulation is not auto regulated
Uterine
CBF auto regulation shifted to right in …. and left in ….
Chronic HTN
Neonates and they have narrow range of MAP
Isoflurane produces …. waves on EEG at … MAC
Isoelectric at 2 MAC
The best measure for ICP control during resection of Supranational tumor is …. and maintaining…. and avoiding ….?
Mannitol and maintaining normocarbia. Avoiding hyperventilating to not further decreasing CBF to compromised brain tissue area???
Complications of hypertonic mannitol?
Volume expansion
Hyperosmolality
HypoNa
Likely occur in RF or large doses
The goal of anesthetic during clipping of intracranial aneurysm?
Maintenance of CPP and transmural pressure gradient (TMPG)
Sudden increase in MAP or decrease in ICP will change in TMPG and will make aneurysm vulnerable for rupture
When is the optimal time to unclamped the lumber drain during intracranial aneurysm repair?
After surgeon opens the dura.
If it’s unclamped before a sudden decrease in ICP May result in change in TMPG and the aneurysm rupture
DI vs SIADH vs cerebral salt wasting
Differentiated by Volume status and serum Na
DI hypovolemia + hyperNa
SIADH hypervolemia + hypoNa
CSW. Down down both hypoV hypoNa
During posterior fossa craniotomy, the pressure transducer should be zeroed at the level of
External auditory meatus
… most sensitive method to detect Air embolism and …. is second most sensitive
TEE
Percordial doppler
The risk of air embolism is higher in …. and … positions
Sitting and reverse trendelenburg
During air embolism the …, …, … falls as there is decreased perfusion through the lung
EtCO2, N2O, nitrogen
The tip of multiorifice CVP catheter to aspirate air in air embolism situation should be ..
2 cm below SVC-RA junction
Management of air embolism?
Flood the surgical field with normal saline. Compress the internal jugular.
Place in left lateral decubitus, trendelenburg to prevent the embolism to go to RV into plum artery
A bradycardia results from stimulation of … during post fossa craniotomy and best managed by …
vasomotor center
Stop stimulation
Bradycardia during squint surgery due to stimulation of
Occlucardiac reflex
Oculocardiac reflex pathway ophthalmic division of trigeminal (… and …) -> … ganglion -> … ganglion -> vagus nerve.
ophthalmic division of trigeminal (long and short ciliary nerves) -> ciliary ganglion -> Gasserian ganglion -> vagus nerve.
