A Comparison Between Two Video Laryngoscopes,in Successfully Intubating Pediatric Mannequins w/wo Difficult Airways

Overview

The study is a randomized crossover study where anesthesia practitioners will intubate three different pediatric infant mannequins (normal airway, anterior larynx, Pierre Robin syndrome anatomy) using three different intubation devices (the Miller blade, the Truview VL, the Glidescope Cobalt video-laryngoscope) in two different scenarios (normal neck and with an immobile neck). The order of presentation will be randomized. As this is a cross over study, all subjects will complete all scenarios. There is no placebo group, and each subject wil be his or her own control.

Participants will be given individual, standardized instructions and demonstrations for each device as per the manufacturers' instructions. The participants will practice with instructor's feedback on an infant mannequin with a normal airway until he/she feel comfortable with each of the three devices. The investigator will record the prior experience of the participant in using each of the 3 devices in clinical situations. Each subject will be asked to intubate each of the mannequins with each of the devices. The choice of the order of device and mannequin will be based on a Latin square design and the sequence will be assigned to participants based on a computer generated random number. A closed envelope technique will blind participants and investigators to the order of airway device and mannequin till the start of the individual trial. Participants will first finish the test on unchanged conditions and then repeat the process using the same order of mannequins and devices but with the neck held immobile to simulate a scenario of a child with an unstable cervical spine. Data from different scenarios will be recorded from a total number of 18 attempts of tracheal intubation per participant. Participants will be asked to proceed as though they were in the operating room with an assistant available to follow their commands. The order of presentation of each mannequin, airway device and scenario will be randomized as described above. The time from placing the device in the mannequin's mouth to the time the Ambu bag is connected to the end of the tracheal tube and a positive pressure breath is given will constitute the intubation time. During each intubation the participant will be asked to state when he or she has obtained the best view for intubation and this time this will be recorded as the time for visualization. The subject will assess the quality of the best glottic view on the Cormack - Lehane grade of 1 -4. The investigators will record all maneuvers to optimize visualization of the larynx such as tracheal pressure, lip retraction, pulling the tongue forward etc. The time from entry of the device in the mouth to the time the tracheal tube is started to be advanced is the visualization time. The time a positive pressure breath is given at the end of the tracheal tube will constitute the end of the attempt of intubation. A failed attempt is defined as removal of the laryngoscope from the mouth without a successful intubation. The number of times the endotracheal tube is advanced will also be recorded. Failure of intubation will be defined as unrecognized esophageal intubation, abandoned procedure, intubation taking longer than 120 seconds and intubation requiring more than 3 attempts. The observer will estimate the maximum force applied to the maxilla on a 0 -10 scale where 0= no force and 10 = maximum force with distortion of the maxilla. The observer will also estimate potential damage of laryngeal structures on a 0 -10 scale.