Table 1. Effect of different anesthetic agents on evoked potentials

Anesthetic agents	Latency	Amplitude	Notes
1. Inhalation anesthesia
Volatile agents	↑	↓	Isoflurane >sevoflurane or desflurane, Effect increases at MAC >0.5
Nitrous oxide	↑	↓	Potent effect on neuronal nicotinic acetylcholine receptors
2. Intravenous anesthesia
Propofol	↑ Dose dependent	↑ Dose dependent	Rapid metabolism/titration, drug of choice during TIVA
Barbiturates	↑↑	↓↓	EPs are very sensitive to barbiturate
Midazolam	↑	↓	Marked suppression of all EPs in high dose
Ketamine	↑	↑	Potential risk for IICP, but enhance EP quality in combination with TIVA
Etomidate	↓	↑	Enhance EP quality in combination with TIVA
Dexmedetomidine	↑ or →	↑ or →	Combination with other agents in TIVA to decrease dose of other agentsVariable effect or scarcity of data
Fentanyl	→ EPs at high doses	Minimal to ↓ Dose dependent	Commonly used in TIVA.
Remifentanil	→ EPs at high doses	Minimal to ↓ Dose dependent	Commonly used in TIVA. Rapid metabolism/titration
3. Muscle relaxants			Abolish MEPs and EMG totally. No effect to SSEP, BAEP

MAC: minimal alveolar concentration; EP: evoked potential; IICP: increased intracranial pressure; TIVA: total intravenous anesthesia; MEP: motor-evoked potential; EMG: electromyography; SSEP: somatosensory evoked potentials; BAEP: brainstem auditory evoked potentials.