Influence of Dexmedetomidine on the Evoked Potentials During Spine Surgery

The purposes of this study are:

1. To evaluate the safety and efficacy of Dexmedetomidine as an adjunct for anesthesia during spine surgery and
2. To investigate the influence of Dexmedetomidine on the evoked potentials.

Study Overview

• Status: Completed
• Conditions: Spine Surgery
• Intervention / Treatment: Drug: Dexmedetomidine; Drug: Normal Saline

Detailed Description

Use of evoked potentials can significantly improve neurologic outcome after major spine surgery. Modalities of evoked potentials commonly used are Somato-Sensory Evoked Potentials (SSEP's), Motor Evoked Potentials (MEP's), and Visual Evoked Potentials (VEP's).

Dexmedetomidine (DEX) is an alpha-2 agonist and has been FDA approved as an adjunct sedative agent to general anesthesia. It has been purported to reduce the amount of anesthetic required and potentiate the analgesic effect of opiates. In addition, DEX was shown to have minimal effect on SSEP's and VEP's in both rats and humans. Any decrease in the dose of general anesthesia that improves the monitoring of evoked potentials, supports DEX as an adjunct.

It is known that all anesthetic agents can interfere with the recording of evoked potentials. The choice of anesthetic however, depends on the modality of neurophysiologic monitoring planned for the patient. Total intravenous anesthesia (TIVA) and Sevoflurane, a low dose inhalational anesthetic are the usual agents for spine surgery. Both have a dose-related depressant effect on the quality of evoked potentials. As a result, it is common practice for the anesthesiologist to adjust the depth of anesthesia to improve signaling. The use of either anesthetic must accompany continuous infusion of Propofol and an opioid, Remifentanil or Fentanyl. The anesthesiologist then decides whether DEX should be as an adjunct. In our experience, DEX did not impair evoked potentials. In fact, it improved the quality of signals in a few patients. Yet, there are no published data of such effects in medical literature.

We hypothesize that Dexmedetomidine will not influence evoked potentials when used as an adjunct to general anesthesia. Our study is prospective, randomized, double-blinded and will be carried out on a set of anesthetics. We will first evaluate DEX as an adjunct in TIVA, then as an adjunct to Sevoflurane. The probable benefit of DEX may avoid the use of potent inhaled anesthetics which would improve VEP's monitoring. Quality recording of evoked potentials can enhance our ability to detect iatrogenic injury to the spinal cord and vision.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Washington
    • Seattle, Washington, United States, 98195
      • University of Washington Medical Center
    • Seattle, Washington, United States, 98104
      • Harborview Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Adult spine surgery patients requiring evoked potentials monitoring.

Exclusion Criteria:

• Age younger than 18 and older than 80 years
• Patients with moderate neurological deficit
• ASA grade above 3
• Any chronic psychiatric disorder
• Body mass index (BMI) above 35
• Patients with cortical blindness, cataracts, retinal or optic neuropathy, glaucoma, untreated diabetes, active hepatitis, active coronary artery disease, untreated arrhythmias and patients with renal or hepatic insufficiency

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Dexmedetomidine; Dexmedetomidine infusion	Drug: Dexmedetomidine; 10 minutes loading dose of 0.9 mcg/kg Maintenance dose of 0.6 mcg/kg/hour; Other Names: Dexmedetomidine hydrochloride
Placebo Comparator: Placebo; Normal Saline infusion	Drug: Normal Saline; 10 minutes loading dose of 0.9 mcg/kg Maintenance dose of 0.6 mcg/kg/hour; Other Names: 0.9% Sodium Chloride

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change in evoked potentials	Duration of surgery

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: Hospira, now a wholly owned subsidiary of Pfizer
• Investigators: Principal Investigator: Irene Rozet, MD, University of Washington

Publications and helpful links

General Publications

• Rozet I, Metzner J, Brown M, Treggiari MM, Slimp JC, Kinney G, Sharma D, Lee LA, Vavilala MS. Dexmedetomidine Does Not Affect Evoked Potentials During Spine Surgery. Anesth Analg. 2015 Aug;121(2):492-501. doi: 10.1213/ANE.0000000000000840.

Study record dates

Study Major Dates

• Study Start: February 1, 2008
• Primary Completion (Actual): May 1, 2010
• Study Completion (Actual): May 1, 2010

Study Registration Dates

• First Submitted: June 28, 2007
• First Submitted That Met QC Criteria: June 28, 2007
• First Posted (Estimate): July 2, 2007

Study Record Updates

• Last Update Posted (Estimate): September 14, 2012
• Last Update Submitted That Met QC Criteria: September 12, 2012
• Last Verified: September 1, 2012

More Information

Terms related to this study

• Keywords: Dexmedetomidine; Spine surgery; Evoked potentials
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Analgesics, Non-Narcotic; Adrenergic alpha-2 Receptor Agonists; Adrenergic alpha-Agonists; Adrenergic Agonists; Hypnotics and Sedatives; Dexmedetomidine
• Other Study ID Numbers: 31416-A; 064705 A01 (Other Identifier: University of Washington)