Difficult Laryngoscopy Scenarios Research Articles

A comparison of the Trachway intubating stylet and the Macintosh laryngoscope in tracheal intubation: a manikin study

The Trachway intubating stylet (Trachway(®)), when used by experienced anesthesiologists, has been shown to be effective for difficult airway management. We evaluated the efficacy of this intubating stylet for tracheal intubation in a manikin when used by experienced laryngoscopists with little experience using this device. Thirty-eight nurse anesthesiologists intubated the trachea of a manikin (Laerdal Airway Management Trainer) with a Trachway intubating stylet or a Macintosh laryngoscope in easy and difficult laryngoscopy scenarios. The duration of the intubation attempts, success rates, dental trauma, and ease of use (0=very easy; 10=very difficult) were recorded. The primary endpoint was the duration of the successful tracheal intubation attempt in the difficult laryngoscopy scenario. Data are presented as means (SD). Both devices resulted in similar tracheal intubation performance in the easy laryngoscopy scenario. However, the Trachway intubating stylet provided shorter intubation times (20.8±5.6 vs. 25.5±7.3s; p=0.003) and easier intubations (2.4±1.6 vs. 5.7±1.8; p<0.001) compared with the Macintosh laryngoscope in the difficult laryngoscopy scenario. All tracheal intubations were successful and no dental trauma was observed when using the Trachway intubating stylet. We concluded that the Trachway intubating stylet, when used by novices, is effective in both easy and difficult laryngoscopy scenarios. In difficult laryngoscopy scenarios, this device provided faster, easier, and less traumatic intubation than the Macintosh laryngoscope.

Efficacy of the Airtraq® laryngoscope with a fiberoptic bronchoscope compared with that of Airtraq® alone for tracheal intubation: a manikin study

Successful intubation using the Airtraq(®) requires optimal positioning of the glottis in the middle of the viewfinder. If the glottic view cannot be optimized, some glottic manipulation is essential for the Airtraq-assisted successful intubation. We evaluated the efficacy of the combined use of the Airtraq and a fiberoptic bronchoscope (FOB) compared with that of the Airtraq alone for tracheal intubation in simulated airway scenarios. Eight anesthesia providers (four staff and four residents) were enrolled in this study. The participants intubated the trachea of the ALS Simulator manikin in five tongue edema scenarios simulating modified Cormack-Lehane grade 1, 2a, 2b, 3, and 4 views and one cervical immobilization scenario. No significant difference in the rate of successful intubation was detected between the combined use and the use of Airtraq alone in all scenarios. However, the duration of intubation attempts with the combined use was significantly shorter in difficult laryngoscopy scenarios (Cormack-Lehane grade 2b-4) (P<0.01) and were significantly longer in easy laryngoscopy scenarios (grade 1 and 2a) (P<0.05) than those with Airtraq alone. The rate of successful intubation and duration of intubation attempts were similar between the anesthetists and residents in each intubation technique in all scenarios. The combined use of Airtraq(®) and a FOB enables rapid intubation in simulated difficult airway scenarios compared with intubation using Airtraq alone, and the speed of intubation performed by anesthetists and residents is similar in all airway scenarios.

Correspondence: Comparison of the C‐MAC® videolaryngoscope with the Macintosh, Glidescope® and Airtraq® laryngoscopes in easy and difficult laryngoscopy scenarios in manikins

The C-MAC comprises a Macintosh blade connected to a video unit. The familiarity of the Macintosh blade, and the ability to use the C-MAC as a direct or indirect laryngoscope, may be advantageous. We wished to compare the C-MAC with Macintosh, Glidescope and Airtraq laryngoscopes in easy and simulated difficult laryngoscopy. Thirty-one experienced anaesthetists performed tracheal intubation in an easy and difficult laryngoscopy scenario. The duration of intubation attempts, success rates, number of intubation attempts and of optimisation manoeuvres, the severity of dental compression, and difficulty of device use were recorded. In easy laryngoscopy, the duration of tracheal intubation attempts were similar with the C-MAC, Macintosh and Airtraq laryngoscopes; the Glidescope performed less well. The C-MAC and Airtraq provided the best glottic views, but the C-MAC was rated as the easiest device to use. In difficult laryngo-scopy the C-MAC demonstrated the shortest tracheal intubation times. The Airtraq provided the best glottic view, with the Macintosh providing the worst view. The C-MAC was the easiest device to use.

Comparison of the C‐MAC® videolaryngoscope with the Macintosh, Glidescope®, and Airtraq® laryngoscopes in easy and difficult laryngoscopy scenarios in manikins

The C-MAC comprises a Macintosh blade connected to a video unit. The familiarity of the Macintosh blade, and the ability to use the C-MAC as a direct or indirect laryngoscope, may be advantageous. We wished to compare the C-MAC with Macintosh, Glidescope and Airtraq laryngoscopes in easy and simulated difficult laryngoscopy. Thirty-one experienced anaesthetists performed tracheal intubation in an easy and difficult laryngoscopy scenario. The duration of intubation attempts, success rates, number of intubation attempts and of optimisation manoeuvres, the severity of dental compression, and difficulty of device use were recorded. In easy laryngoscopy, the duration of tracheal intubation attempts were similar with the C-MAC, Macintosh and Airtraq laryngoscopes; the Glidescope performed less well. The C-MAC and Airtraq provided the best glottic views, but the C-MAC was rated as the easiest device to use. In difficult laryngo-scopy the C-MAC demonstrated the shortest tracheal intubation times. The Airtraq provided the best glottic view, with the Macintosh providing the worst view. The C-MAC was the easiest device to use.

Determination of the optimal stylet strategy for the C‐MAC® videolaryngoscope

The C-MAC videolaryngoscope is a novel intubation device that incorporates a camera system at the end of its blade, thereby facilitating obtaining a view of the glottis without alignment of the oral, pharyngeal and tracheal axes. It retains the traditional Macintosh blade shape and can be used as a direct or indirect laryngoscope. We wished to determine the optimal stylet strategy for use with the C-MAC. Ten anaesthetists were allowed up to three attempts to intubate the trachea in one easy and three progressively more difficult laryngoscopy scenarios in a SimMan manikin with four tracheal tube stylet strategies: no stylet; stylet; directional stylet (Parker Flex-It); and hockey-stick stylet. The use of a stylet conferred no advantage in the easy laryngoscopy scenario. In the difficult scenarios, the directional and hockey-stick stylets performed best. In the most difficult scenario, the median (IQR [range]) duration of the successful intubation attempt was lowest with the hockey-stick stylet; 18 s (15-22 [12-43]) s, highest with the unstyletted tracheal tube; 60 s (60-60 [60, 60]) s and styletted tracheal tube 60 s (29-60 [18-60]) s, and intermediate with the directional stylet 21 s (15-60 [8-60]) s. The use of a stylet alone does not confer benefit in the setting of easy laryngoscopy. However, in more difficult laryngoscopy scenarios, the C-MAC videolaryngoscope performs best when used with a stylet that angulates the distal tracheal tube. The hockey-stick stylet configuration performed best in the scenarios tested.

A comparison of the Glidescope®, Pentax AWS®, and Macintosh laryngoscopes when used by novice personnel: a manikin study

Direct laryngoscopic tracheal intubation is a potentially lifesaving procedure, but a difficult skill to acquire and maintain. The consequences of poorly performed intubation attempts are potentially severe. The Pentax AWS and the Glidescope are indirect laryngoscopes that may require less skill to use. We therefore hypothesized that AWS and Glidescope would prove superior to the Macintosh laryngoscope when used by novices in the normal and simulated difficult airway. In this prospective randomized crossover trial following standardized didactic instruction, medical students with no prior experience of laryngoscopy performed tracheal intubation using each device. Each student was allowed up to three attempts to intubate in a Laerdal Intubation Trainer in two laryngoscopy scenarios and in a Laerdal SimMan manikin in one scenario. The students then performed tracheal intubation of the normal airway a second time to characterize the learning curve for each device. The Pentax AWS provided better intubation conditions than the Glidescope or the Macintosh, resulting in greater success of intubation, particularly in the difficult laryngoscopy scenarios. The Glidescope demonstrated advantages over the Macintosh, particularly in the more difficult scenarios. Both the AWS and the Glidescope decreased the duration of intubation attempts, reduced the number of maneuvers required, and reduced the potential for dental trauma. In direct comparisons, the AWS provided the best intubation conditions. The Pentax AWS appears to constitute a better alternative to the Macintosh for novice personnel to acquire the skills of tracheal intubation.

Retention of tracheal intubation skills by novice personnel: a comparison of the Airtraq® and Macintosh laryngoscopes*

Direct laryngoscopic tracheal intubation is a potentially lifesaving manoeuvre, but it is a difficult skill to acquire and to maintain. These difficulties are exacerbated if the opportunities to utilise this skill are infrequent, and by the fact that the consequences of poorly performed intubation attempts may be severe. Novice users find the Airtraq laryngoscope easier to use than the conventional Macintosh laryngoscope. We therefore wished to determine whether novice users would have greater retention of intubation skills with the Airtraq rather than the Macintosh laryngoscope. Twenty medical students who had no prior airway management experience participated in this study. Following brief didactic instruction, each took turns performing laryngoscopy and intubation using the Macintosh and Airtraq devices in easy and simulated difficult laryngoscopy scenarios. The degree of success with each device, the time taken to perform intubation and the assistance required, and the potential for complications were then assessed. Six months later, the assessment process was repeated. No didactic instruction or practice attempts were provided on this latter occasion. Tracheal intubation skills declined markedly with both devices. However, the Airtraq continued to provide better intubating conditions, resulting in greater success of intubation, with fewer optimisation manoeuvres required, and reduced potential for dental trauma, particularly in the difficult laryngoscopy scenarios. The substantial decline in direct laryngoscopy skills over time emphasise the need for continued reinforcement of this complex skill.

Learning and performance of tracheal intubation by novice personnel: a comparison of the Airtraq® and Macintosh laryngoscope

Direct laryngoscopic tracheal intubation is taught to many healthcare professionals as it is a potentially lifesaving procedure. However, it is a difficult skill to acquire and maintain, and, of concern, the consequences of poorly performed intubation attempts are potentially serious. The Airtraq Laryngoscope is a novel intubation device which may possess advantages over conventional direct laryngoscopes for use by novice personnel. We conducted a prospective trial with 40 medical students who had no prior airway management experience. Following brief didactic instruction, each participant took turns in performing laryngoscopy and intubation using the Macintosh and Airtraq devices under direct supervision. Each student was allowed up to three attempts to intubate in three laryngoscopy scenarios using a Laerdal Intubation Trainer and one scenario in a Laerdal SimMan Manikin. They then performed tracheal intubation of the normal airway a second time to characterise the learning curve for each device. The Airtraq provided superior intubating conditions, resulting in greater success of intubation, particularly in the difficult laryngoscopy scenarios. In both easy and simulated difficult laryngoscopy scenarios, the Airtraq decreased the duration of intubation attempts, reduced the number of optimisation manoeuvres required, and reduced the potential for dental trauma. The Airtraq device showed a rapid learning curve and the students found it significantly easier to use. The Airtraq appears to be a superior device for novice personnel to acquire the skills of tracheal intubation.

Evaluation of intubation using the Airtraq® or Macintosh laryngoscope by anaesthetists in easy and simulated difficult laryngoscopy – a manikin study*

The Airtraq Laryngoscope is a novel intubation device which allows visualisation of the vocal cords without alignment of the oral, pharyngeal and tracheal axes. We compared the Airtraq with the Macintosh laryngoscope in simulated easy and difficult laryngoscopy. Twenty-five anaesthetists were allowed up to three attempts to intubate the trachea in each of three laryngoscopy scenarios using a Laerdal Intubation Trainer followed by five scenarios using a Laerdal SimMan Manikin. Each anaesthetist then performed tracheal intubation of the normal airway a second time to characterise the learning curve. In the simulated easy laryngoscopy scenarios, there was no difference between the Airtraq and the Macintosh in success of tracheal intubation. The time taken to intubate at the end of the protocol was significantly lower using the Airtraq (9.5 (6.7) vs. 14.2 (7.4) s), demonstrating a rapid acquisition of skills. In the simulated difficult laryngoscopy scenarios, the Airtraq was more successful in achieving tracheal intubation, required less time to intubate successfully, caused less dental trauma, and was considered by the anaesthetists to be easier to use.

Evaluation of ease of intubation with the GlideScope® or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy*

The GlideScope is a new video laryngoscope developed for management of the difficult airway. We compared the GlideScope with the Macintosh laryngoscope in simulated easy and difficult laryngoscopy. Twenty anaesthetists were allowed three attempts to intubate in each of four laryngoscopy scenarios in a high fidelity simulator. In the simulated easy laryngoscopy scenarios, the anaesthetists took longer to intubate using the GlideScope than the Macintosh laryngoscope (mean (SD) 19.0 (9.7) s vs. 12.7 (5.9) s, respectively; p = 0.006). There was no difference in the number of successful intubations, ease of intubation or choice of intubating device. In the simulated difficult laryngoscopy scenarios, the anaesthetists took less time to intubate using the GlideScope (23.5 (12.7) s vs. 70.5 (101.2) s, respectively; p = 0.001). The slightly higher success rate with the GlideScope was not statistically significant (20/20 vs. 18/20, respectively; p = 0.5). However, the anaesthetists found it easier to intubate using the GlideScope (median (interquartile range [range]) 1 (1-2 [1-2]) vs. 2 (2-3 [1-3]), respectively; p < 0.0001).