Neuro Cases and Considerations Flashcards
do you give benzos preop for Neuro cases
no, when they wake up postop the surgeon will want to do a neuro exam. if they cant, its aNeStHeSiAs fAuLt
in general, anesthetic drugs do what to CMR?
depress CMR
anesthetic drugs that do not depress CMR
ketamine and nitrous oxide
preop considerations
general assessment including IV access
normal postop eval
neuro assessment
med assessment (anticonvulsants)
medications used intraop
continue antiseizure usually ancef and vanc as abx diuretics mannitol steroids (usually a big dose up front)
preop considerations: head positioning with mayfield pins
premedicate before stimulation with 2cc remi or prop bolus
-these pins are sharp, patient will bleed
MEP neuromonitoring (motor evoked potentials)
used in surgeries where motor tract is at risk
direct and scalp electrodes
more sensitive to ischemia than SSEP by 15 minutes and degree detection
pt bleeds when these are taken out-theyre like screws
SSEP neuromonitoring (somatosensory)
most commonly monitored
stimulation of peripheral sensory nerve
mapping in spinal cord and sensory cortex
ischemia detection in cortical tissues
reduce risk of spinal cord/brainstem
mechanical or ischemic insults
-can use paralytic if needed
-does have motor monitoring, not as specific.
-does not measure deficits
-hypothermia can increase latency and decrease amplitude
EMG neuromonitoring (electromyography)
records muscle electrical activity using needle pairs
continuous recording
triggered responses
uses: detect nerve irritation, nerve mapping, assess nerve function, monitoring cranial nerves.
good for spinals to detect if screws are misplaced
which two drugs increase neuromonitoring wave amplitude
ketamine and etomidate
what is stereotactic neurosurgery
applies the rules of geometry to radiologic images to allow for precise localization within the brain, providing up to 1mm accuracy. less invasive approach to certain intracranial procedures. small markers (fudicials) are affixed to scalp and forehead with adhesive. important that these fudicials do not move between time of imaging and entry into OR
anesthesia for stereotactic neurosurgery
smaller brain biopsies may be done under local/mac
GETA for larger resections
craniotomy meds to decrease ICP
decadron 10mg
mannitol 50-100g (.25-.5g/kg)
lasix (+/-)
craniotomy induction meds
fentanyl, prop, rocuronium
craniotomy maintenance meds
TIVA with prop at max 40mcg/kg/min ABW for asleep motor mapping and awake crane
remifentanil .2mcg/kg/min IBW(why doe?)
neo gtt strung up
-increase remi before increasing prop if patient is light
for what types of surgeries can you consider redosing rocuronium
aneurysms, pituitary tumors
craniotomy meds: antiepileptics
keppra 1g, vimpat
craniotomy meds: abx
usually vanc and ancef
craniotomy meds: analgesics
tylenol 30m before close
hydromorphone or fentanyl
drugs specifically for awake crani
caffeine 60mg/3mL (adenosine receptor antagonist)
physostigmine (anti cholinesterase) .5-1mg q2m
why are cranies usually a delayed wake up (not anesthesia related)
CT reveals air that will absorb, delays wake up
types of intracranial mass lesions
congenital
neoplastic (benign versus malignant)
infectious (abcess or cyst)
vascular (hematoma or av malformation)
typical presentation of intracranial mass in order from most reported to least reported sx
HA, seizures, focal neurological deficits, sensory loss, cognitive dysfunction
supratentorial intracranial mass lesions sx (general)
seizures, hemiplegia, aphasia