title: Somatosensory Evoked Potentials suppression due to remifentanil during spinal operations; a prospective clinical study.
abstract: BACKGROUND
  Somatosensory evoked potentials (SSEP) are being used for the investigation and monitoring of the integrity of neural pathways during surgical procedures. Intraoperative neurophysiologic monitoring is affected by the type of anesthetic agents. Remifentanil is supposed to produce minimal or no changes in SSEP amplitude and latency. This study aims to investigate whether high doses of remifentanil influence the SSEP during spinal surgery under total intravenous anesthesia.
  
  
  METHODS
  Ten patients underwent spinal surgery. Anesthesia was induced with propofol (2 mg/Kg), fentanyl (2 mcg/Kg) and a single dose of cis-atracurium (0.15 mg/Kg), followed by infusion of 0.8 mcg/kg/min of remifentanil and propofol (30-50 mcg/kg/min). The depth of anesthesia was monitored by Bispectral Index (BIS) and an adequate level (40-50) of anesthesia was maintained. Somatosensory evoked potentials (SSEPs) were recorded intraoperatively from the tibial nerve (P37) 15 min before initiation of remifentanil infusion. Data were analysed over that period.
  
  
  RESULTS
  Remifentanil induced prolongation of the tibial SSEP latency which however was not significant (p > 0.05). The suppression of the amplitude was significant (p < 0.001), varying from 20-80% with this decrease being time related.
  
  
  CONCLUSIONS
  Remifentanil in high doses induces significant changes in SSEP components that should be taken under consideration during intraoperative neuromonitoring.
authors.affiliation: 2nd Department of Anesthesiology "G,Papanikolaou" General Hospital, Exohi Thessaloniki, Greece. iasouhidou@aol.com.
authors.forename: Irene
authors.initials: I
authors.lastname: Asouhidou
authors.forename: Vasilios
authors.initials: V
authors.lastname: Katsaridis
authors.forename: Georgios
authors.initials: G
authors.lastname: Vaidis
authors.forename: Polimnia
authors.initials: P
authors.lastname: Ioannou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Givissis
authors.forename: Anastasios
authors.initials: A
authors.lastname: Christodoulou
authors.forename: Georgios
authors.initials: G
authors.lastname: Georgiadis
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