Age Influence on the Modifications of the Oral, Pharyngeal and Laryngeal Axis Alignment in Children Induced by Head Extension: an MRI Study
Condition: Head Extension on the Anatomic Axes of the Superior Airway
Study type: Interventional

Summary: 
      In pediatric anesthesia and in pediatric intensive care, tracheal intubation is one of the
      most important procedure. To achieve this procedure as fast as possible and in is best
      conditions, the physician should choose the head posture which a priori will enable at first
      the best glottic visualisation during laryngoscopy, and at second will facilitate the route
      of the tube from the larynx to the trachea.

      Tracheal intubation is a procedure used for years, and many textbooks recommendations on the
      best head posture for tracheal intubation in paediatrics have been made. Briefly summarized,
      depending on the age of the child, the head should (or not) be slightly extended, and a
      pillow should (or not) be positioned under the occiput. These recommendations are
      questionable for three majors reasons:

        -  despite an apparent consensus, some recommendations are quite different.

        -  none are based on anatomical nor clinical studies

        -  if for all of them, the age of the child is considered as critical point, but children
           are only grossly categorized in three categories (newborn, infants and old children).
           And the clinician has no way, facing a child, to make his choice between dichotomic
           attitudes.

      Actually, the responses to these questions should need rigourous clinical studies on
      laryngoscopy, hard to design and very difficult to make. P.Adnet et coll. (Anesthesiology
      2001) showed that an anatomical study with resonance magnetic imaging (MRI) can bring
      indirect but strong evidence and can be a first step leading to clinical studies. Many
      children need MRI study for different reasons, and it is fast and easy to get during their
      examination additional images of the superior airway.

      In their unit, the investigators are experienced in this kind of study, as they recently
      published (Pediatric Anesthesia 2008) an MRI study demonstrating that in children, head
      extension improves the alignment of the visualisation axis on the laryngeal axis, but worsens
      the alignment of the pharyngeal axis on the laryngeal axis. However, patients included in
      their study were in major part infants, so the influence of the age could not be properly
      analyzed. Morevover, this study suffered of two main limitations, the lack of standardisation
      of head postures, and that a laryngeal mask the children, who were on general anesthesia
      (required for the MRI examination) were made using a laryngeal mask (as it was at this time
      the standard in their institution).

      The investigators propose an MRI study of the influence of age on the consequences of head
      extension on the anatomic axes of the superior airway in children, with a prospective
      stratified on age study. Several modifications and improvement in the design of this study
      would diminished the limitations of the first study.
    


Intervention name(s): MRI
Intervention type(s): Procedure
Intervention description(s): MRI during 35 to 65 minutes
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: child