Videolaryngoscopes for Double Lumen Tube Intubations
Condition: Thoracic Surgery; Need for Double Lumen Tubes
Study type: Interventional

Summary: 
      Introduction: Compared with the Macintosh laryngoscopy (MAC), the videolaryngoscopes (VL)
      provide superior glottis views and longer times to double-lumen tube (DLT) intubation. We
      hypothesize that the use of the King Vision™ (KVL) and the Airtraq® VLs may reduce the time
      for DLT intubation compared with the Glidescope® (GVL) and MAC in patients undergoing
      thoracic procedures.

      Methods: One hundred-forty patients who will be scheduled for elective thoracic procedures
      using the DLT for one-lung ventilation will be randomly assigned to one of four groups (n=35
      per group) to intubate using the MAC, GVL, Airtraq®, or KVL. Time to DLT intubation, glottis
      view, ease of intubation, number of optimization maneuvers, and failure to intubation (>150
      s.) will be recorded.
    

Detailed description: 
      Several regional surveys among thoracic anesthesiologists showed that the double-lumen
      endobronchial tubes (DLT) is still the first choice for lung separation.[1-3] The
      introduction of videolaryngoscopes (VL) enables the use of the DLTs instead of a bronchial
      blockers for lung separation in patients with difficult airway.[4-5]

      There are numerous VLs, including, stylets, channeled and traditional VLs. The
      GlideScope®-assisted DLT insertion (Verathon Inc., Bothell, WA, USA), has been associated
      with variable intubation durations according to the experience of the intubating operators,
      despite superior vocal cord views.[6-7] The channeled VL, like as the Airtraq® (Prodol
      Limited, Viscaya, Spain) and the standard non-channeled blade of the King Vision™ (KVL™)
      (King Systems, Indianapolis, IN, USA), may offer additional benefits for DLT intubation in
      patients with limited mouth opening or restricted neck movement, [8-10] in whom the use of
      traditional VL like as the Glidescope® could be difficult. This is because of the larger
      outer diameter, the distal curvature and the increased rigidity of the DLT.[11]

      Of note, the longer intubation durations with the use of different VL-assisted DLT insertion
      could be shortened with building up the operator's experience.

      Comparing the effects of the three studied VLs on the time to DLT intubation in humans has
      not yet been studied.

      We hypothesize that time to successful DLT intubation using the channeled VL, namely, the
      Airtraq® and KVL™, will be shorter than with the Macintosh (MAC) laryngoscope and GlideScope®
      VL when used by non-expert anesthesiologists. We will compare the effects of the MAC,
      GlideScope®, Airtraq® and KVL™ on the time to DLT intubation, laryngoscopic view, ease of
      intubation, number of intubation attempts, and number of optimization maneuvers in patients
      undergoing thoracic procedures using DLTs for one-lung ventilation (OLV).

      Standard monitoring, and bispectral index (BIS), or state and response entropy based depth of
      anesthesia, (GE Healthcare, Helsinki, Finland) will be applied to all patients. Neuromuscular
      blockade will be measured with a train of four stimulation (TOF) of the ulnar nerve. Invasive
      blood pressure monitoring will be achieved by cannulation of the radial artery. After
      preoxygenation, general anesthesia will be induced with propofol 1.5 to 3mg kg-1 and fentanyl
      2-3 µg kg-1 or remifentanil 0.05-0.2 ug Kg-1 min-1, titrated to achieve a BIS value < 60 or a
      state entropy values of less than 50 and a difference between response and state entropy of
      less than 10. Rocuronium (0.6 mg kg-1) will be given to facilitate intubation with an
      appropriate sized left-sided DLT.

      In all groups, during the insertion of the DLT, exercise caution to avoid damage to the
      tracheal cuff by the upper teeth during its passage through the mouth opening. After DLT
      intubation, the tracheal cuff will be inflated and ventilation of the lungs commenced. Then,
      the correct position of its tip will be confirmed with a fiberoptic bronchoscope.

      The first intubation attempt will be considered a failure if the trachea is not successfully
      intubated within 150 s or if the peripheral oxygen saturation (SpO2) decreases by 5%.
      Following an initial tracheal intubation failure, the participants will be allowed to use any
      maneuver and device they would normally use to navigate the DLT into the trachea.

      Demographic data will be recorded including grade, experience with the VLs, and previous DLT
      intubation experience with the VLs.

      All data, with the exception of the difficulty of device use score, will be recorded by
      blinded investigators.

      A pilot study showed that the mean time to DLT intubation using the GlideScope® VL was 72
      seconds with a standard deviation of 45.2 seconds. An a priori power analysis indicated that
      a sample size of 32 participants was sufficiently large to detect a 50% difference in the
      time to DLT intubation, during the use of the channeled VL, a type-I error of 0.008 (0.05/6
      possible comparisons) and a power of 90%. We will add more patients (10%) for a final sample
      size of 35 participants to compensate dropping out during the study.

      Data will be tested for normality using Kolmogorov-Smirnov test. Categorical data will be
      analyzed using the Fisher's exact test. Repeated-measures analysis of variance (ANOVA) will
      be used for continuous parametric variables, and the differences will be corrected by the
      post hoc Bonferroni test. Kruskal-Wallis test will be used for nonparametric values, and post
      hoc pairwise comparisons will be performed using the Wilcoxon rank-sum t test Continuous data
      will be presented as mean (standard deviation, SD), ordinal data will be presented as median
      (inter-quartile range), and categorical data will be presented as number (%). A value of p<
      0.05 will be considered to be statistically significant.
    

Intervention name(s): Macintosh; Glidescope®; Airtraq®; King Vision™
Intervention type(s): Device; Device; Device; Device
Intervention description(s): double lumen tube intubation using the Macintosh laryngoscope; double lumen tube intubation using the Glidescope® videolaryngoscope. The distal portion of a left-sided DLT will be angulated to the right concealing the distal orifice of the tracheal lumen. The DLT will be advanced directly through the vocal cords after initial 90° clockwise rotation, the stylet will be removed, and then the DLT will be advanced gently while rotating in a 180° couterclockwise direction; double lumen tube intubation using the Airtraq® videolaryngoscope.; double lumen tube intubation using the King Vision™ videolaryngoscope. the distal 21 cm of the left-sided DLT will be bended to replicate the curve of the non-channeled blade and the proximal curve of the DLT remains directed to the right side. Then, after initial 90° clockwise rotation, the bronchial cuff passes through the vocal cords, the stylet of the DLT will be withdrawn and the DLT will be rotated 180°counterclockwise while advancing the DLT to the desired depth.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: Laryngoscope; Macintosh; Glidescope®; King Vision™; Airtraq®; intubation; double lumen tube