Randomized controlled trial of the Pentax AWS®, Glidescope®, and Macintosh laryngoscopes in predicted difficult intubation

The purpose of this study was to determine the potential for the Pentax AWS® and the Glidescope® to reduce the difficulty of tracheal intubation in patients at increased risk for difficult tracheal intubation, in a randomized, controlled clinical trial. Seventy-five consenting patients presenting for surgery requiring tracheal intubation, and who were deemed to possess characteristics indicating an increased risk for difficult tracheal intubation, were randomly assigned to undergo intubation using a Macintosh, AWS®, or Glidescope® laryngoscope (n=25 patients per group). All patients were intubated by one of three anaesthetists experienced in the use of each laryngoscope. Both the Glidescope® and the AWS® significantly reduced the intubation difficulty score compared with the Macintosh. The rate of successful tracheal intubation was lower with the Macintosh (84%) compared with the Glidescope® (96%) or the AWS® (100%). There were no differences in the duration of tracheal intubation attempts between the devices. Both the Glidescope® and the AWS® significantly reduced the need for additional manoeuvres and improved the Cormack and Lehane view obtained at laryngoscopy, compared with the Macintosh. Tracheal intubation with the AWS® but not the Glidescope® reduced the degree of haemodynamic stimulation compared with the Macintosh laryngoscope. The AWS® and the Glidescope® laryngoscopes reduced the difficulty of tracheal intubation to a similar extent compared with the Macintosh laryngoscope, in patients at increased risk for difficult tracheal intubation.