A 60-year-old man on ICU is comatose following a cardiac arrest. The neuroprognostication team performs bilateral SSEP testing at 72 hours. Bilaterall...

Question

A 60-year-old man on ICU is comatose following a cardiac arrest. The neuroprognostication team performs bilateral SSEP testing at 72 hours. Bilaterally absent N20 cortical responses are found. Before concluding poor prognosis, what confounders must be excluded?

Accepted Answer

Confounders that can cause falsely absent N20 responses include: residual sedation (particularly barbiturates), therapeutic hypothermia (test should be performed after rewarming), profound hypotension, technical factors (electrode placement, electrical interference), and pre-existing peripheral neuropathy (which can affect afferent conduction to the cortex)

Answer

No confounders exist - absent N20 is always definitive

Answer

Only age affects SSEP

Answer

SSEPs are never affected by any drug

Answer

SSEPs should only be performed within 24 hours

uk-fficm MCQ (SBA): SSEP Confounders

A 60-year-old man on ICU is comatose following a cardiac arrest. The neuroprognostication team performs bilateral SSEP testing at 72 hours. Bilaterally absent N20 cortical responses are found. Before concluding poor prognosis, what confounders must be excluded?