Influence of Dexmedetomidine on the Evoked Potentials During Spine Surgery

Spine Surgery Clinical Trial

Official title:

Influence of Dexmedetomidine on the Evoked Potentials During Spine Surgery

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00494832
• Other study ID #: 31416-A
• Secondary ID: 064705 A01
• Status: Completed
• Phase: N/A
• First received: June 28, 2007
• Last updated: September 12, 2012
• Start date: February 2008
• Est. completion date: May 2010

Study information

• Verified date: September 2012
• Source: University of Washington
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 40
• Est. completion date: May 2010
• Est. primary completion date: May 2010
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 80 Years

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Spine Surgery

Intervention

Drug:
• Dexmedetomidine
10 minutes loading dose of 0.9 mcg/kg Maintenance dose of 0.6 mcg/kg/hour
• Normal Saline
10 minutes loading dose of 0.9 mcg/kg Maintenance dose of 0.6 mcg/kg/hour

Locations

Country	Name	City	State
United States	Harborview Medical Center	Seattle	Washington
United States	University of Washington Medical Center	Seattle	Washington

Sponsors (2)

Lead Sponsor	Collaborator
University of Washington	Hospira, Inc.

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in evoked potentials		Duration of surgery	Yes