Visual Examination of Airway Via Flexible Fiberoptic Scope After Cervical Spine Surgery
Condition: Airway Edema
Study type: Observational

Summary: 
      Airway swelling and edema after cervical spine surgery(CSS) especially in prone position is
      the direct cause that prohibits patient from extubation. Anterior cervical discectomy and
      fusion causes severe peri-vertebral soft tissue swelling that was associated with increased
      postoperative airway complications.

      Facial, lip and tongue edema in combination with the cuff leak test and risk factors are
      currently served as the bases on whether patient can be extubated after spine surgery. Direct
      visualization of the larynx and inside trachea post-operatively to assess the airway directly
      using flexible fiberoptic scope as well as to quantify the degree of airway edema has not
      been investigated.

      Investigators are comparing airway before and after cervical spine surgery for any degree of
      narrowing in the airway using flexible fiberoptic scope. Investigators are also studying the
      risk factors affecting the degree of narrowing in the airway if any
    

Detailed description: 
      Because direct visualization of the airway is the most reliable way for the diagnosing and
      assessing the degree of laryngeal and trachea edema or swelling, investigators sought to do a
      study to evaluate the degree of airway edema in adult patients undergoing for CSS using
      direct visualization via flexible fiberoptic and compare the results pre and post-
      operatively.

      The primary outcome will be severity of larynx and trachea edema after cervical spine
      surgery.

      Secondary outcome will be assessment of reliability of airway leak technique and association
      between face swelling and airway edema.

      18 years old and above, 63 number of patient will be enrolled in the study. Patient enrolled
      who are under going elective cervical spine surgery.Patients involved in the study will be
      taken to the OR, after induction and prior to intubation asleep flexible fiberoptic scope
      will be inserted nasally and video record will be taken above and below the glottis, surgery
      will be continued as planned.

      The primary analysis is to test the association of the severity of the laryngeal and tracheal
      edema with surgical time and number of levels involved in surgery. Investigators will also
      perform an exploratory analysis to examine the impact of other potential risk factor,
      including age, fluids and blood products transfusions, ASA( American Society of
      Anesthesiology) physical status, facial swelling and cuff leak After conclusion of surgery,
      and when patients are ready for extubation. Quantitative cuff leak will be done, flexible
      fiber optic scope will be placed through the endotracheal tube, and at the same time of
      extubation fiber optic scope will be pulled slowly with the endotracheal tube while recording
      video until we reach a point that approximate same point video was taken prior to intubation,
      patients who will remain intubated nasal scope will be placed and video will be taken above
      the glottis with the endotracheal tube in place, another video will be taken for the airway
      from inside the endotracheal tube.

      Study will be aborted if significant resistance during placement of the fiberoptic scope,
      nasal bleeding happens or hypoxemia requiring ventilation.

      Pictures will be saved on USB device and will be assigned a random code that is non-leading
      to which videos were taken before surgery and which were taken after surgery. Recording prior
      to intubation will be done as we are withdrawing the scope out, so the motion will be similar
      to the motion in the video recorded with extubation, hoping that this will be less leading to
      the blinded ENT surgeon to which was taken before and which after. Patient that will be kept
      intubated are not blinded.

      Pictures will be then shown to ENT surgeon to assess and compare preoperative and
      postoperative outcome.

      Severity of the laryngeal tracheal edema is classified into mild, moderate, and severe.
      According to the reduction of the cross-section of the trachea lumen, Mild edema is defined
      as reduction <30%, Moderate < 50%, severe >50% (8).

      ENT surgeon will grade the degree of narrowing in the trachea to:

        1. No edema to < 30%

        2. 31%-50%

        3. > 50%.

      And above the trachea into

        1. none.

        2. mild.

        3. severe.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients undergoing multilevel cervical spine surgery are recruited as study subjects.

        Inclusion and exclusion criteria as described above
      
Keywords: leak test; cervical spine surgery