Table 4.
Operative Effects on Intraoperative Neuromonitoring
| Anesthetic Effect on Electrophysiologic Monitoring | ||||
| Agent | SSEP | MEP | ||
| Volatile anesthetics | Increased latency and decreased amplitude | Depressed | ||
| Nitrous oxide | Decreased amplitude | |||
| Propofol | Increased latency and decreased amplitude | Depressed | ||
| Neuromuscular blockade | – | Depressed | ||
| Opioids | Minimal changes | |||
| Dexmedetomidine | Minimal changes | |||
| Etomidate | Increased amplitude | |||
| Ketamine | Increased amplitude | |||
| Benzodiazepines | – | Depressed | ||
| Physiologic Considerations on Electrophysiologic Monitoring | ||||
| SSEP | MEP | |||
| Lower body temp | Increased latencies | Depressed | ||
| Decreased blood pressure (flow) | <18 mL/100g/m | Increased latencies | ||
| <15 mg/100g/m | Loss of SSEP | |||
| Fluid near nerve roots | – | Depressed | ||
| Surgical Considerations on Electrophysiologic Monitoring | ||||
| Neural Insult | Increased latency and decreased amplitude | Neurotonic discharges | ||