Cervical Spine Biomechanics During Endotracheal Intubation
Condition: Spinal Diseases; Other Biomechanical Lesions of Cervical Region; Tracheal Intubation Morbidity
MeSH terms: Spinal Diseases
Study type: Interventional

Summary: 
      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.
    


Intervention name(s): Endotracheal intubation
Intervention type(s): Procedure
Intervention description(s): 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.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Basic Science
Keywords: Cervical spine; Endotracheal intubation; Laryngoscope; Biomechanics