A comparison of the GlideScope with the Macintosh laryngoscope for tracheal intubation in patients with simulated difficult airway

We compared the use of the GlideScope and the conventional Macintosh laryngoscope in a simulated difficult airway. The primary hypothesis was that time to intubation would be shorter using the GlideScope than using the Macintosh laryngoscope. After obtaining approval from the ethics committee and written informed consent, we recruited 60 ASA 1 and 2 patients to our randomized controlled trial. Group G (n = 30) had tracheal intubation performed using the GlideScope and Group M (n = 30) were intubated using a Macintosh laryngoscope. We simulated a difficult airway in each patient by having an experienced assistant provide in-line manual stabilization of the head and neck. We recorded the best laryngeal view; difficulty of the tracheal intubation; time taken for successful tracheal intubation; manoeuvre needed to aid tracheal intubation and complications associated with the tracheal intubation. The median Cormack and Lehane grade was significantly better in Group G than Group M. Group G had a significantly shorter intubation time than group M (mean 41.8s +/- SD 20.2 vs mean 56.2s +/- 26.6, P < 0.05). The GlideScope improved the laryngeal view and decreased time for tracheal intubation time when compared with the Macintosh laryngoscope in patients with simulated difficult airway. The GlideScope may be a good alternative for managing the difficult airway but clinical trials evaluating its use on patients with an actual difficult airway are needed.     

A randomised, crossover study of the Dorges, McCoy and Macintosh laryngoscope blades in a simulated difficult intubation scenario

The use of alternative adult laryngoscope blades in an unexpected difficult intubation was evaluated with a human patient simulator manikin. Twenty anaesthetists of varying experience attempted to intubate the trachea of a high fidelity simulator in both its normal and difficult intubation settings using Macintosh, Dorges and McCoy laryngoscopes in a randomised order. The time taken to intubate, Cormack and Lehane scores, percentage of glottic opening visible, failure rate, number of attempts and subjective ease of use were recorded. The Dorges and McCoy blades did not perform any better than the standard Macintosh blade in either the easy or difficult tracheal intubation settings. Guidelines recommending the use of an alternative blade in an unexpected difficult intubation scenario have limited supporting evidence. This study does not support this recommendation.     

预计困难插管患者使用Airtraq喉镜、Shikani喉镜和Macintosh喉镜行气管插管的比较

目的 探讨Airtraq喉镜、Shikani喉镜和Macintosh喉镜在预计困难插管患者中行气管插管的应用价值.方法 行全麻插管手术预计困难插管患者75例,随机分为Airtraq喉镜组(A组)、Shikani喉镜组(S组)和Macintosh喉镜组(M组),三次内插管成功者入选本研究,每组25例.记录插管时间,麻醉诱导前(T1)、诱导后(T2)、插管结束即刻(T3)和插管后3 min(T4)时的MAP和HR.同时观察各组患者的声门暴露程度以及有无咽喉损伤.结果 A组插管时间最短,其次为S组,M组最慢,A组明显短于S组和M组(P＜0.05).A组插管成功率高于S组和M组(P＜0.05).与T2时比较,T3、T4时M组MAP明显升高、HR明显增快(P＜0.05).T3、T4时M组MAP高于A组,HR快于A组(P＜0.05).A组声门完全显露率最高,其次为S组,M组最低,A组明显优于S组和M组(P＜0.05).A组咽喉损伤发生率低于M组(P＜0.05).结论 在预计困难插管条件下,与Shikani喉镜和Macintosh喉镜比较,使用Airtraq喉镜可以缩短插管时间,提高插管成功率,减少气管插管时心血管应激反应,维持血流动力学稳定,降低咽喉损伤的发生率.     

A comparison of the ease of tracheal intubation using a McGrath MAC® laryngoscope and a standard Macintosh laryngoscope

We compared the McGrath MAC^® videolaryngoscope when used as both a direct and an indirect laryngoscope with a standard Macintosh laryngoscope in patients without predictors of a difficult tracheal intubation. We found higher median Intubation Difficulty Scores with the McGrath MAC as a direct laryngoscope, 1 (0–3 [0–5]) than when using it as an indirect videolaryngoscope, 0 (0–1 [0–5]) or when using the Macintosh laryngoscope, 0 (0–1 [0–5]), p = 0.04. This was mirrored in the subjective user reporting, scored out of 10, of difficulty for each method 3.0 (2.0–3.4 [0.5–80]); 2.0 (1.0–3.9 [0–70]) and 2.0 (1.0–3.3 [0–70]), respectively (p = 0.01). This difficulty is in part explained by the poorer laryngeal views recorded using the Cormack and Lehane classification system (p < 0.001) and reflected in the higher than normal operator force required (25%, 4%, 8% for each method, respectively, p < 0.001) and the increased use of rigid intubation aids (21%, 6%, 2%, respectively, p < 0.001). There was no difference between the groups in time taken to intubate or incidence of complications. There was no statistical difference in the performances as measured between the McGrath MAC used as an indirect videolaryngoscope and the Macintosh laryngoscope. We cannot recommend that the McGrath videolaryngoscope be used as a direct laryngscopic device in place of the Macintosh.     

A comparison of tracheal intubation using the Airtraq or the Macintosh laryngoscope in routine airway management: A randomised, controlled clinical trial

The Airtraq laryngoscope is a novel single use tracheal intubation device. We compared the Airtraq with the Macintosh laryngoscope in patients deemed at low risk for difficult intubation in a randomised, controlled clinical trial. Sixty consenting patients presenting for surgery requiring tracheal intubation were randomly allocated to undergo intubation using a Macintosh (n = 30) or Airtraq (n = 30) laryngoscope. All patients were intubated by one of four anaesthetists experienced in the use of both laryngoscopes. No significant differences in demographic or airway variables were observed between the groups. All but one patient, in the Macintosh group, was successfully intubated on the first attempt. There was no difference between groups in the duration of intubation attempts. In comparison to the Macintosh laryngoscope, the Airtraq resulted in modest improvements in the intubation difficulty score, and in ease of use. Tracheal intubation with the Airtraq resulted in less alterations in heart rate. These findings demonstrate the utility of the Airtraq laryngoscope for tracheal intubation in low risk patients.     

HC视频喉镜与Macintosh喉镜引导气管插管效果的比较

目的 比较HC视频喉镜与Macintosh喉镜引导气管插管的效果.方法 择期全麻患者60例,ASA分级Ⅰ或Ⅱ级,性别不限,年龄18 ～ 64岁,体重指数19 ～ 27 kg/m2,Mallampati分级Ⅰ或Ⅱ级,采用随机数字表法,将其随机分为2组(n=30):HC视频喉镜组(H组)和Macintosh喉镜组(M组).麻醉诱导后分别用HC视频喉镜和Macintosh喉镜引导经口气管插管.记录两组患者声门暴露时间、气管插管时间、Cormack-Lehane分级(用于计算声门暴露满意率)、环状软骨按压情况,观察气管插管并发症的发生情况.结果 与M组比较,H组声门暴露满意率升高,环状软骨按压次数降低(P＜0.05).两组患者声门暴露时间、气管插管时间和气管插管并发症发生率差异无统计学意义(P＞0.05).结论 HC视频喉镜引导气管插管的效果优于Macintosh喉镜.     

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

Purpose

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.

Methods

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).

Results

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 ± 7.3 s; 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.

Conclusion

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.     

A new curved laryngoscope blade for routine and difficult tracheal intubation

We have designed a new curved laryngoscope blade based on a new concept of reversing the peardrop phenomenon to facilitate a view of the larynx sufficient for intubation in a greater variety of patients than the current Macintosh blade affords. The new design has a bifid tip and S-shaped spatula to exert more effective pressure in the vallecula area, elevate the epiglottis and change directions of the forces on the tongue to prevent posteroinferior displacement of the compressed tongue in the submandibular space during laryngoscopy. A radiograph laryngoscopy technique was used to guide the new blade curvature design and compare the performance of the new blade with the Macintosh blade in patients with or without a difficult airway. Our results confirm that the new blade provides a laryngeal view sufficient to accomplish intubation by compressing the root of the tongue in an anterocephalad direction in the submandibular space and elevating the epiglottis effectively in patients with or without unanticipated difficult airway. The new curved blade can also effectively move the U-shaped epiglottis out of the laryngeal view to facilitate intubation in pediatric patients aged 2 mo-13 yr.     

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).     

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.     

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.