Effects of propofol, etomidate, midazolam and fentanyl on motor evoked responses to transcranial electrical or magnetic stimulation in humans

The effect of two low‐dose propofol infusions on the relationship between six‐pulse transcranial electrical stimulation and the evoked lower extremity muscle response

“…The effect of the induction dose of diazepam and fentanyl is limited after 10–20 min and a stable MEP is observed ( 3). The use of a target controlled infusion (TCI) of propofol is more and more accepted as an intravenous technique for the maintenance of anaesthesia ( 8).…”

“…Doubling the propofol infusion not only causes a deeper level of anaesthesia but, very likely, sets up inhibitory events to electrical stimulation at the level of the motor cortex. In our setup, those inhibitory events cannot be ruled out to be active at the motor neuron pool in the anterior horn as well ( 3).…”

“…Monitoring of motor evoked responses to transcranial electrical stimulation (tcMEP) may be useful in reflecting the functional integrity of the vulnerable motor pathways during thoracoabdominal aneurysm surgery ( 2). The depressive effects of most anaesthetic regimens interfere considerably with the recording of tcMEPs evoked by single or double electrical stimulation ( 3). Neuromuscular blocking drugs also decrease the tcMEP response ( 4).…”