Which laryngeal mask for fiberoptic-aided wire-guided catheter exchange tracheal intubation? The Classic-LMATM or the Proseal-LMATM: a mannequin study

摘要

Study Objective: To compare the ease of use, operator preference, time to completion, and failure rates while performing a fiberoptic-aided wire-guided airway exchange tracheal intubation through the the LMA-Classic TM and LMA-Proseal TM.Design: Prospective, randomized trialSetting: SimulationInterventions: Twenty-five participants of various experience grades performed four intubations each, one hundred intubations total, on an AirSim TM airway trainer through a #3 laryngeal mask using a fiberoptic endoscope and an Arndt Airway Exchange Catheter Set.Measurements: Laryngeal view after LMA insertion was graded by one of the investigators. The time to intubation and any intubation failures were recorded. Participants were asked to rate the ease of performing the intubation through each LMA and which device they preferred.Main Results: Intubation was reported to be easier through the cLMA than the pLMA. Consequently, participants preferred the cLMA for use as an airway conduit. However, the time to completion and failure rates were essentially the same in all groups. First attempt intubation success rate was 92% overall.Conclusion: Fiberoptic-aided wire-guided catheter exchange intubation can be performed successfully through either the cLMA or the pLMA. Personal experience with each device should dictate which device is chosen initially. Grants, sponsors, and funding sources The AirSim TM airway trainer used in this study was supported by intramural departmental funds Introduction Use of a laryngeal mask (LMA) as a conduit for fiberoptic-aided tracheal intubation when unanticipated airway difficulty is encountered has been previously reported. One such technique, which utilizes a pre-packaged, commercially available, wire-guided airway exchange catheter set (Arndt Airway Exchange Catheter Set, Cook Critical Care, Bloomington, Indiana) and an LMA Classic TM (cLMA, LMA North America, Inc., San Diego, California) as the airway conduit has been reported in the setting of the adult critical airway (1). The cLMA was so chosen by the authors based upon reports of superior visualization of the laryngeal aperture compared to other laryngeal mask devices (2-3). However, the relatively low-pressure pharyngeal seal of the cLMA (median pressure 16-22 cmH2O) (4) may limit its utility under commonly encountered situations in the intensive care unit (ICU). In contrast, the LMA-prosealTM (pLMA, LMA North America, Inc., San Diego, California) creates a pharyngeal seal that is on average 50% higher than the cLMA (4) and the presence of a built-in esophageal drain tube allows confirmation of the functional separation of the respiratory and alimentary tracts. This may be an advantage in the ICU in the presence of both a difficult airway and when high inflation pressures are needed for effective ventilation (5). Nonetheless, compared to the cLMA, the termination of the airway tube of the pLMA is further back and slightly off-center from the glottic opening, possibly making it more difficult to intubate the trachea with a fiberoptic endoscope (FOS). Therefore, the primary aim of our study was to compare ease of use, operator preference, time to completion, and failure rates while performing a fiberoptic-aided wire-guided airway exchange tracheal intubation through the cLMA and the pLMA. Materials and Methods The University of Wisconsin Health Sciences Minimal Risk Institutional Review Board approved the study. Written informed consent was obtained from all participants. Twenty-five physicians were invited and agreed to participate in the study (5 senior staff, 5 fellows, 5 third-year anesthesia trainees, 5 second-year anesthesia trainees, and 5 first-year anesthesia trainees). The 5 anesthesia staff were chosen for their considerable experience in this technique and served as the reference standard for intergroup comparisons. The least experienced anesthesia trainee had performed > 25 fiberoptic intubations in the operating room prior to participation