Susceptibility of Motor-Evoked Potentials to Varying Targeted Blood Levels of Dexmedetomidine
Status:
Completed
Trial end date:
2009-01-01
Target enrollment:
Participant gender:
Summary
Reduction of the spinal cord injuries during scoliosis surgery is a major goal of the
anesthesia and surgical team. Despite improvement in scoliosis surgery over the years, the
development of neurological deficits remains the most feared complication of spine surgery.
During scoliosis surgery it is very important to monitor the spinal cord to detect spinal
cord injury with surgical manipulation. Continuous or intermittent intraoperative
electrophysiological monitoring (neuron-monitoring) is used routinely during these procedures
to provide the surgeon with information concerning the integrity of neurological structures
at risk. All neuron-monitoring modalities are affected by the anesthetic regimen used. Of the
various intravenous anesthetic drugs, the combination of propofol, remifentanil and
dexmedetomidine appear to impact neuron-monitoring the least. The current anesthetic practice
is to use the three drugs in combination at doses that do not depress the signals but there
is no data relating targeted dexmedetomidine and propofol blood levels to neuron-monitoring
signals. The lack of data results in wide variability in dosing with consequent variability
in patient response.
Hypothesis: Clinically relevant blood levels of dexmedetomidine will affect the amplitude of
transcranial motor-evoked potentials (TcMEP) either independently or by interaction with
propofol in a dose dependent manner.