SSEP and MEP Flashcards
When neuromonitoring, you need to have baseline what?
Baseline SSEP and MEP
SSEP: Compromise or injury to the pathway results in:
increase in latency and decrease in amplitude of evoked potential waveform
What do SSEPs evaluate?
The functional integrity of the ascending sensory pathways
A ___% reduction in amplitude is considered to be:
significant and warrants a change in action-either by anesthesia or the surgeon.
Don’t forget to place ___ during MEPs!
Bite block
What are some indications for SSEPs?
- Intramedullary/extramedullary spinal cord tumors or cysts
- Vascular lesions in spine
- Cervical or thoracic spine herniated discs that cause spinal cord compression
- Spinal cord decompression and stabilization after acute spinal cord injury
Benzos in low doses-do they affect SSEPs?
no, not at low doses
IV induction doses of thiopental, propofol, ketamine, or etomidate-does this affect SSEPs?
Not at induction doses, but propofol and thiopental can have an effect when given at high doses
How do high concentrations of volatiles affect SSEPs?
Dose dependent increase in latency and decrease in amplitude. Up to 0.5 Mac is acceptable
How does nitrous affect SSEPs? What about MEPs?
profound depressant effect on SSEPs-especially when used in combo with a volatile anesthetic. Nitrous doesn’t affect MEPs as much
Opioids and SSEPs?
minimal effect
SSEPs and temp?
Pressure?
Hypoxia?
Anemia
Temp-normothermic is what patient should be.
Pressure-hypotension decreases amplitude
Hypoxia: produces SSEP changes including decrease in amplitude
Anemia: increased latency
MEPs test what:
Integrity of descending motor pathway
Indications for MEP:
- Intramedullary (growths in the spinal cord-glial (non neuronal) cells) spinal cord tumors
- Removal of cerebral tumors involving motor Cortex or subcortical motor pathways
Contraindications to transcranial MEP:
hx of seizure
skull fracture
cardiac pacemakers
Central venous or PAC
