36 - 40 SBAs for the Final FRCA

36 - 40 SBAs for the Final FRCA
Photo by Unseen Studio / Unsplash

Question 36

You are anaesthetisting a 7 year old girl for scoliosis surgery.

Which of the following is least likely to affect the spinal cord monitoring during surgery?

  • Ketamine
  • Nitrous oxide
  • Isoflurane
  • Alfentanil
  • Midazolam


  • Alfentanil

When discussing spinal cord monitoring we're usually referring to somatosensory and motor evoked potentials, or SSEPs and MEPs.

Volatile agents decrease the amplitude of these signals and increase the latency.

Ketamine increase the amplitude.

Nitrous oxide and midazolam reduce amplitude.

Propofol and opioids have the least impact on spinal cord monitoring so usually these cases are done under propofol and remifentanil TIVA.