Cervical Spine Biomechanics During Endotracheal Intubation

This study has been completed.
Sponsor:
Collaborators:
National Institute for Biomedical Imaging and Bioengineering (NIBIB)
Colorado State University
Information provided by (Responsible Party):
Bradley J. Hindman, University of Iowa
ClinicalTrials.gov Identifier:
NCT01369381
First received: May 31, 2011
Last updated: August 3, 2012
Last verified: August 2012
  Purpose

Current methods for endotracheal intubation in the presence of cervical spine (c-spine) instability are not evidence-based. This is so because the relationships between the forces applied during intubation (by the laryngoscope) and the resulting c-spine movement have not yet been quantitatively characterized. As a result, with the current level of knowledge, it is not known, and it is not possible to predict, which types of c-spine instability have the greatest risk of cervical spinal cord injury with intubation. This shortcoming makes it impossible to know which intubation devices and techniques are likely to be safest in the presence of c-spine instability.

To address this critical lack of knowledge, the overarching purpose of the proposed research is to: 1) quantitatively relate c-spine movement that results from the forces applied to the peri-airway tissues during intubation (force-motion relationships), and 2) use these data to develop a mathematical model of the c-spine that will predict which types of c-spine instability result in the greatest amount of abnormal c-spine motion and associated spinal cord compression during intubation.

This clinical study will utilize laryngoscope blades that are instrumented with a high resolution pressure mapping system to make high-resolution measurements of the forces and pressures of intubation while making simultaneous measurements of c-spine motion. In this study, study subjects will be intubated using both a conventional (Macintosh) laryngoscope and an alternative (Airtraq) laryngoscope. By using two different laryngoscopes, we, the investigators, will introduce forces of differing magnitudes and distributions to peri-airway tissues. The Airtraq does not require a direct line of sight to visualize the vocal cords, and among the various new alternative laryngoscopes it is the only one that has been shown to result in 30-50% less cervical motion than a conventional (Macintosh) laryngoscope. Accordingly, we hypothesize 1) 30-50% less force will be applied with the Airtraq laryngoscope than with the conventional (Macintosh) laryngoscope and 2) 30-50% less c-spine motion will occur with the Airtraq. By studying (intubating) each subject twice, any differences in the c-spine force-motion relationships between devices will be due to the devices themselves. By studying each subject twice, we can account for (and eliminate) differences among study subjects in c-spine biomechanical properties.


Condition Intervention
Spinal Diseases
Other Biomechanical Lesions of Cervical Region
Tracheal Intubation Morbidity
Procedure: Endotracheal intubation

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Intubation Mechanics of the Stable and Unstable Cervical Spine

Resource links provided by NLM:


Further study details as provided by University of Iowa:

Primary Outcome Measures:
  • Cervical spine segmental intervertebral motion [ Time Frame: Data collection takes place during two sequential endotracheal intubations (40-45 seconds), with follow-up assessments on postoperative days 1, 3, and 7. ] [ Designated as safety issue: No ]
    Lateral fluoroscopy is used to measure cervical spine motion during endotracheal intubation.


Secondary Outcome Measures:
  • Laryngoscope blade force distribution [ Time Frame: Data collection takes place during two sequential endotracheal intubations (40-45 seconds), with follow-up assessments on postoperative days 1, 3, and 7. ] [ Designated as safety issue: No ]
    "Pressure-mat" technology is used to measure spacially distributed forces applied by the laryngoscope blade during endotracheal intubation.

  • Glottic visualization [ Time Frame: Data collection takes place during two sequential endotracheal intubations (40-45 seconds), with follow-up assessments on postoperative days 1, 3, and 7. ] [ Designated as safety issue: No ]
    An image of the glottis during intubation is obtained for off-line measurement of the percentage of glottic opening as seen by the laryngoscopist.


Enrollment: 14
Study Start Date: December 2011
Study Completion Date: July 2012
Primary Completion Date: July 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Airtraq laryngoscope
The Airtraq is an alternative indirect laryngoscope that appears to cause less cervical spine motion during intubation that conventional direct laryngoscopy (Macintosh blade)
Procedure: Endotracheal intubation
Study patients undergo endotracheal intubation using both a conventional direct laryngoscope (Macintosh) and an alternative indirect laryngoscope (Airtraq). The order of intubation (Macintosh then Airtraq--or--Airtraq then Macintosh) is randomized.
Active Comparator: Macintosh laryngoscope
This arm constitutes intubation with a conventional direct laryngoscopy with a Macintosh blade which has been shown to result in cervical spine extension, particularly in the upper cervical segments.
Procedure: Endotracheal intubation
Study patients undergo endotracheal intubation using both a conventional direct laryngoscope (Macintosh) and an alternative indirect laryngoscope (Airtraq). The order of intubation (Macintosh then Airtraq--or--Airtraq then Macintosh) is randomized.

  Eligibility

Ages Eligible for Study:   18 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Patient Height: 5-feet, 0-inches to 6-feet, 0-inches
  • Patient body mass index: less than 30 kg/m2
  • Planned surgery requires use of C-arm fluoroscopy
  • Planned surgery to take place at University of Iowa and requires general anesthesia and orotracheal intubation

Exclusion Criteria:

  • The patient is a prisoner
  • The patient is pregnant
  • The patient is not competent to personally give consent
  • Neurological signs and symptoms indicating cervical spinal cord myelopathy
  • Cervical spine images demonstrating anatomic instability, traumatic injury, significant cervical stenosis, and/or spinal immobility
  • Condition associated with cervical spine anatomic abnormalities such as Rheumatoid arthritis, Down Syndrome, Ankylosing spondylitis, Osteogenesis imperfecta
  • Prior cervical spine surgery of any type
  • History of difficult endotracheal intubation
  • Currently symptomatic gastroesophageal reflux disease
  • Currently symptomatic asthma or other reactive airway disease
  • Any history of coronary artery disease
  • Any history of cerebral aneurysm(s)
  • History of vocal cord and/or glottic disease or dysfunction
  • Contraindication to receiving 100% oxygen
  • Systolic blood pressure greater than 180 mmHg
  • Diastolic blood pressure greater than 100 mmHg
  • American Society of Anesthesiologists Physical Status class of 4, 5, or 6
  • Known allergy or other adverse response to study drugs: midazolam, lidocaine, fentanyl, propofol [eggs, soy beans], rocuronium, or sevoflurane.
  • Mallampati oropharyngeal class of III or IV
  • Thyromental distance less than 6.0 cm
  • Sternomental distance less than 12.5 cm
  • Maxillary incisors loss or in poor condition
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01369381

Locations
United States, Iowa
University of Iowa Hospitals and Clinics
Iowa City, Iowa, United States, 52242
Sponsors and Collaborators
University of Iowa
National Institute for Biomedical Imaging and Bioengineering (NIBIB)
Colorado State University
Investigators
Principal Investigator: Bradley J Hindman, M.D. University of Iowa
  More Information

Publications:
Responsible Party: Bradley J. Hindman, Professor, Department of Anesthesia, University of Iowa
ClinicalTrials.gov Identifier: NCT01369381     History of Changes
Other Study ID Numbers: 201102721, R01EB012048
Study First Received: May 31, 2011
Last Updated: August 3, 2012
Health Authority: United States: Institutional Review Board

Keywords provided by University of Iowa:
Cervical spine
Endotracheal intubation
Laryngoscope
Biomechanics

Additional relevant MeSH terms:
Spinal Diseases
Bone Diseases
Musculoskeletal Diseases

ClinicalTrials.gov processed this record on September 30, 2014