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

Routine Use of Videolaryngoscopy in Airway Management

Tracheal intubation is a fundamental facet of airway management, for which the importance of achieving success at the first attempt is well recognized. Failure to do so can lead to significant morbidity and mortality if there is inadequate patient oxygenation by alternate means. The evidence supporting the benefits of a videolaryngoscope in attaining this objective is now overwhelming (in adults). This has led to its increasing recognition in international airway management guidelines and its promotion from an occasional airway rescue tool to the first-choice device during routine airway management. However, usage in clinical practice does not currently reflect the increased worldwide availability that followed the upsurge in videolaryngoscope purchasing during the coronavirus disease 2019 pandemic. There are a number of obstacles to widespread adoption, including lack of adequate training, fears over de-skilling at direct laryngoscopy, equipment and cleaning costs, and concerns over the environmental impact, among others. It is now clear that in order for patients to benefit maximally from the technology and for airway managers to fully appreciate its role in everyday practice, proper training and education are necessary. Recent research evidence has addressed some existing barriers to default usage, and the emergence of techniques such as awake videolaryngoscopy and video-assisted flexible (bronchoscopic) intubation has also increased the scope of clinical application. Future studies will likely further confirm the superiority of videolaryngoscopy over direct laryngoscopy, therefore, it is incumbent upon all airway managers (and their teams) to gain expertise in videolaryngoscopy and to use it routinely in their everyday practice..

The Clinical Usability Evaluation of an Attachable Video Laryngoscope in the Simulated Tracheal Intubation Scenario: A Manikin Study

The aim of this study was to assess the usefulness of an attachable video laryngoscope (AVL) by attaching a camera and a monitor to a conventional Macintosh laryngoscope (CML). Normal and tongue edema airway scenarios were simulated using a manikin. Twenty physicians performed tracheal intubations using CML, AVL, Pentax Airwayscope® (AWS), and McGrath MAC® (MAC) in each scenario. Ten physicians who had clinical experience in using tracheal intubation were designated as the skilled group, and another ten physicians who were affiliated with other departments and had little clinical experience using tracheal intubation were designated as the unskilled group. The time required for intubation and the success rate were recorded. The degree of difficulty of use and glottic view assessment were scored by participants. All 20 participants successfully completed the study. There was no difference in tracheal intubation success rate and intubation time in the normal airway scenario in both skilled and unskilled groups. In the experienced group, AWS had the highest success rate (100%) in the tongue edema airway scenario, followed by AVL (60%), MAC (60%), and CML (10%) (p = 0.001). The time required to intubate using AWS was significantly shorter than that with AVL (10.2 s vs. 19.2 s) or MAC (10.2 s vs. 20.4 s, p = 0.007). The difficulty of using AVL was significantly lower than that of CML (7.8 vs. 2.8; p < 0.001). For the experienced group, AVL was interpreted as being inferior to AWS but better than MAC. Similarly, in the unskilled group, AVL had a similar success rate and tracheal intubation time as MAC in the tongue edema scenario, but this was not statistically significant. The difficulty of using AVL was significantly lower than that of CML (8.8 vs. 3.3; p < 0.001). AVL may be an alternative for VL.

Tracheal Intubation during Advanced Life Support Using Direct Laryngoscopy versus Glidescope® Videolaryngoscopy by Clinicians with Limited Intubation Experience: A Systematic Review and Meta-Analysis

The use of the Glidescope® videolaryngoscope might improve tracheal intubation performance in clinicians with limited intubation experience, especially during cardiopulmonary resuscitation (CPR). The objective of this systematic review and meta-analysis is to compare direct laryngoscopy to Glidescope® videolaryngoscopy by these clinicians. PubMed/Medline and Embase were searched from their inception to 7 July 2020 for randomized controlled trials, including simulation studies. Studies on adult patients or adult-sized manikins were included when direct laryngoscopy was compared to Glidescope® videolaryngoscopy by clinicians with limited experience in tracheal intubation (<10 intubations per year). The primary outcome was the intubation first-pass success rate. Secondary outcomes were time to successful intubation and chest compression interruption duration during intubation. The risk of bias was assessed with the Cochrane risk of bias tool. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). We included 4 clinical trials with 525 patients and 20 manikin trials with 2547 intubations. Meta-analyses favored Glidescope® videolaryngoscopy over direct laryngoscopy regarding first-pass success (clinical trials: risk ratio [RR] = 1.61; 95% confidence interval [CI]: 1.16−2.23; manikin trials: RR = 1.17; 95% CI: 1.09−1.25). Clinical trials showed a shorter time to achieve successful intubation when using the Glidescope® (mean difference = 17.04 s; 95% CI: 8.51−25.57 s). Chest compression interruption duration was decreased when using the Glidescope® videolaryngoscope. The certainty of evidence ranged from very low to moderate. When clinicians with limited intubation experience have to perform tracheal intubation during advanced life support, the use of the Glidescope® videolaryngoscope improves intubation and CPR performance compared to direct laryngoscopy.

Educational suitability of new channel-type video-laryngoscope with AI-based glottis guidance system for novices wearing personal-protective-equipment

The aim of this study was to determine which of 4 laryngoscopes, including A-LRYNGO, a newly developed channel-type video-laryngoscope with an embedded artificial intelligence-based glottis guidance system, is appropriate for tracheal intubation training in novice medical students wearing personal protective equipment (PPE).Thirty healthy senior medical school student volunteers were recruited. The participants underwent 2 tests with 4 laryngoscopes: Macintosh, McGrath, Pentax Airway-Scope and A-LRYNGO. The first test was conducted just after a lecture without any hands-on workshop. The second test was conducted after a one-on-one hands-on workshop. In each test, we measured the time required for tracheal intubation, intubation success rate, etc, and asked all participants to complete a short questionnaire.The time to completely insert the endotracheal tube with the Macintosh laryngoscope did not change significantly (P = .177), but the remaining outcomes significantly improved after the hands-on workshop (all P < .05). Despite being novice practitioners with no intubation experience and wearing PPE, the, 2 channel-type video-laryngoscopes were associated with good intubation-related performance before the hands-on workshop (all P < .001). A-LRYNGO's artificial intelligence-based glottis guidance system showed 93.1% accuracy, but 20.7% of trials were guided by the vocal folds.To prepare to manage the airway of critically ill patients during the coronavirus disease 2019 pandemic, a channel-type video-laryngoscope is appropriate for tracheal intubation training for novice practitioners wearing PPE.

Comparison of a New Video Intubation Stylet and McGrath® MAC Video Laryngoscope for Intubation in an Airway Manikin with Normal Airway and Cervical Spine Immobilization Scenarios by Novice Personnel: A Randomized Crossover Study

The use of both a video laryngoscope and a video intubation stylet, compared with the use of a direct laryngoscope, is not only easier to learn but also associated with a higher success rate in performing endotracheal intubation for novice users. However, data comparing the two video devices used by novice personnel are rarely found in literature. Nondelayed intubation is an important condition to determine the prognosis in critically ill patients; hence, exploring intubation performance in various situations is of clinical significance. This study is aimed at comparing a video stylet and a video laryngoscope for intubation in an airway manikin with normal airway and cervical spine immobilization scenarios by novice personnel. We compared the performance of intubation by novices between the Aram Video Stylet and the McGrath® MAC video laryngoscope in an airway manikin. Thirty medical doctors with minimal experience of endotracheal intubation attempted intubation on a manikin five times with each device in each setting (normal airway and cervical spine immobilization scenarios). The order of use of the devices in each scenario was randomized for each participant. In the normal airway scenario, the Aram stylet showed a significantly higher rate of successful intubation than the McGrath® (98.7% vs. 92.0%; odds ratio (95% CI): 6.4 (1.4–29.3); p = 0.006). The intubation time was shorter using the Aram Stylet than that using the McGrath® video laryngoscope (p < 0.001). In the cervical immobilization scenario, successful endotracheal intubation was also more frequent using the Aram stylet than with the McGrath® (96.0% vs. 87.3%; odds ratio (95% CI): 3.5 (1.3–9.0); p = 0.007). The Aram Stylet intubation time was shorter (p < 0.001). In novice personnel, endotracheal intubation appears to be more successful and faster using the Aram Video Stylet than the McGrath® MAC video laryngoscope.

Protection afforded by respirators when performing endotracheal intubation using a direct laryngoscope, GlideScope®, and i-gel® device: A randomized trial

Emergency physicians are at risk of infection during invasive procedures, and wearing a respirator can reduce this risk. The aim of this study was to determine whether the protection afforded by a respirator during intubation is affected by the type of airway device used. In this randomized crossover study, 26 emergency physicians underwent quantitative fit tests for a N95 respirator (cup-type or fold-type) before and during intubation with a direct laryngoscope, GlideScope®, or i-gel® airway device. The primary outcome was the fit factor value of the respirator and the secondary outcome was the level of acceptable protection provided (percentage of fit factor scores above 100). Compared with the GlideScope and i-gel device, the fit factor values and level of acceptable protection provided were lower when physicians wore the cup-type respirator while intubating using the direct laryngoscope (200 fit factor [152–200] and 200 fit factor [121.25–200] versus 166 fit factor [70–200], 100% and 100% versus 75%, respectively; all P < 0.001). There were no significant differences in the fit factor value or level of acceptable protection provided when the physicians wore the fold-type respirator while intubating using any of the three airway devices (all P > 0.05). The type of airway device used for endotracheal intubation may influence the protective performance of some types of respirators. Emergency physicians should consider the effects of airway device types on fit factor of N95 respirators, when they perform intubation at risk of infection.

Comparison of the GlideScope® with the Macintosh Laryngoscope in Endotracheal Intubation during Uninterrupted Mechanical Chest Compression: A Randomised Crossover Manikin Study

Background

The GlideScope® (GS) has been shown to improve the first-attempt success rate of endotracheal intubation during continuous mechanical chest compressions compared with the conventional Macintosh laryngoscope (ML) in inexperienced hands. Yet, its value for operators with experience of emergency airway management has remained uncertain. We set out to compare their performance in the hands of experienced operators in a manikin receiving continuous mechanical chest compressions delivered by LUCAS®.

Method

This was a randomised crossover study. Thirty-five emergency physicians and intensivists performed intubation using GS and ML in 3 different scenarios: (1) normal airway without chest compressions; (2) normal airway with uninterrupted mechanical chest compressions; and (3) normal airway with cervical spine (C-spine) immobilisation and uninterrupted mechanical chest compressions. The sequence of scenarios and devices used were randomised. The primary outcome was the first-attempt success rate of intubation. Other data including demographics, the time required for successful intubation, complications during intubation, the visual analog scale of perceived difficulty of intubation and the preference on devices in each scenario were also collected and analyzed.

Results

In scenario 1, the first-attempt success rate with both laryngoscopes was 100%. In scenario 2, there was a higher first-attempt success rate with ML but it was not statistically significant (GS 97.14% vs ML 100%, p=1.00). In scenario 3, one participant failed to intubate in the first attempt with each of the laryngoscopes (GS 97.14% vs ML 97.14%, p=0.754). More dental compression was noted with GS but the difference was not statistically significant (GS 42.86% vs ML 22.86%, p=0.126). Overall, the median time for intubation with GS was significantly longer in all 3 scenarios (Scenario 1: GS 18.5s; interquartile range [IQR] 13.8 -22.2s vs ML 11.2s, IQR 9.5-14.2s, p<0.001; Scenario 2: GS 18.7s, IQR 13.1-25.2s vs ML 13.4s, 10.3-15.8s, p<0.001; Scenario 3: GS 20.8s, IQR 16.5-29.2s vs ML 14.0s, IQR 10.5-18.0s, p<0.001). More participants preferred GS in scenario 3, while ML remained the device of choice in the other two scenarios. Conclusion: GS is not superior to ML in terms of the first-attempt success rate of intubation and it takes significantly longer to intubate for experienced operator. Yet more participants prefer its use when the C-spine motion is limited. Further studies are warranted to explore its role in trauma resuscitation. (Hong Kong j.emerg.med. 2016;23:159-167)

Efficacy of Pentax airway scope versus Macintosh laryngoscope when used by novice personnel: A prospective randomized controlled study

Objective

To determine whether intubation education using the Pentax Airway Scope (AWS) in normal airways is more useful than direct laryngoscopy (Macintosh laryngoscope) in novice personnel.

Methods

Eleven intern doctors without intubation experience performed 60 sequential intubations with each device on a manikin and 10 sequential intubations in adult patients. The time required for successful intubation, percentage of glottic opening (POGO) score, number of intubation attempts, and number of dental injuries were analyzed for each intubation technique.

Results

The mean (standard deviation) time required for successful intubation decreased as the number of intubations increased and was significantly shorter with the Pentax AWS than direct laryngoscope [22.6 (7.3) vs. 29.6 (10.0) and 33.0 (8.0) vs. 44.7 (5.6) s, respectively] in both the manikin and clinical studies. The Pentax AWS was also associated with higher POGO scores than the direct laryngoscope [81.7 (8.9) vs. 55.1 (13.2) and 80.9 (9.7) vs. 49.6 (16.5), respectively] and fewer intubation attempts. Fewer dental injuries occurred with the Pentax AWS in the manikin study.

Conclusions

Novices performed intubation more rapidly and easily with an improved laryngeal view using the Pentax AWS. We suggest that intubation education with video laryngoscopy should be mandatory along with direct laryngoscope training.

Endotracheal Intubation Using a Direct Laryngoscope and the Protective Performances of Respirators: A Randomized Trial

Purpose. Emergency physicians are at risk for infection during invasive procedures, and the respirators can reduce this risk. This study aimed to determine whether endotracheal intubation using direct laryngoscopes affected protection performances of respirators. Methods. A randomized crossover study of 24 emergency physicians was performed. We performed quantitative fit tests using respirators (cup type, fold type without a valve, and fold type with a valve) before and during intubation. The primary outcome was respirators' fit factors (FF), and secondary outcomes were acceptable protection (percentage of scores above 100 FF [FF%]). Results. 24 pieces of data were analyzed. Compared to fold-type respirator without a valve, FF and FF% values were lower when participants wore a cup-type respirator (200 FF [200-200] versus 200 FF [102.75-200], 100% [78.61-100] versus 74.16% [36.1-98.9]; all P < 0.05) or fold-type respirator with a valve (200 FF [200-200] versus 142.5 FF [63.50-200], 100% [76.10-100] versus 62.50% [8.13-100]; all P < 0.05). There were no significant differences in intubation time and success rate according to respirator types. Conclusions. Motion during endotracheal intubation using direct laryngoscopes influenced the protective performance of some respirators. Therefore, emergency physicians should identify and wear respirators that provide the best personalized fit for intended tasks.

Effects of an elevated position on time to tracheal intubation by novice intubators using Macintosh laryngoscopy or videolaryngoscopy: randomized crossover trial

Objective

To investigate the time to tracheal intubation using Glidescope videolaryngoscopy (GVL) compared to that of standard laryngoscopy, by using a Macintosh blade (SLM) in a human patient simulator in supine and elevated (ramped) positions.

Methods

In this randomized crossover design, novice intubators (first-year medical students), using both laryngoscopic techniques, attempted tracheal intubation on a human patient simulator with a “normal airway” anatomy (Cormack-Lehane grade I). The simulator was placed in both supine and ramped positions using a commercial mattress system. The mean time to intubation and complications were compared between GVL and SLM in both positions. The percentage of glottic opening (POGO, GVL only) was estimated during intubation in the ramped and supine positions. The primary outcome was time to intubation, and the secondary outcomes included complication rates such as esophageal intubation and dental trauma.

Results

There was no difference in the mean time to intubation in either position (P=0.33). The SLM intubation was significantly faster than GVL (mean difference, 1.5 minutes; P<0.001). The mean POGO score for GVL improved by 8% in the ramped position compared to that in supine position (P=0.018). The esophageal intubation rate for SLM was 15% to 17% compared to 1.3% for GVL; dental trauma occurred in 53% to 56% of GVL, compared to 2% to 6% for SLM (P<0.001, respectively).

Conclusion

Novices had shorter intubation times using standard laryngoscopy with a SLM compared to GVL in both supine and ramped positions. GVL resulted in fewer esophageal intubations, but more dental trauma than standard laryngoscopy.

Usefulness of video-laryngoscopy with the Airway Scope for intubation performance and learning: an experimental manikin controlled study

Background

Different video-laryngoscopes (VDLs) for endotracheal intubation (ETI) have recently been developed. We compared the performance of the VDL Airway Scope (AWS) with the direct laryngoscopy by Macintosh (DLM) for ETI success, time and learning.

Methods

We performed an experimental manikin controlled study. Twenty experienced (experts) and 40 inexperienced operators (novices) for DLM-ETI were enrolled. None of them had experience with the use of AWS-VDL. Novices were assigned to start learning with DLM or AWS, and two sub-groups of 20 novices were formed. Experts group constituted the control group. Each participant performed 10 ETI attempts with each device on the same standard manikin. The primary endpoint was the ETI success probability. Secondary endpoints were ETI time, technical validity and qualitative evaluation for each technique. We also assessed the learning order and the successive attempts effects for these parameters.

Results

Overall, 1200 ETI attempts were performed. ETI success probability was higher with the AWS than with the DLM for all operators (98 vs. 81 %; p < 0.0001) and for experts compared to novices using devices in the same order (97 vs. 83 %; p = 0.0002). Overall ETI time was shorter with the AWS than with the DLM (13 vs. 20 s; p < 0.0001) and for experts compared to novices using devices in the same order (11 vs. 21 s; p < 0.0001). Among novices, those starting learning with AWS had higher ETI success probability (89 vs. 83 %; p = 0.03) and shorter ETI time (18 vs. 21 s; p = 0.02). Technical validity was found better with the AWS than DLM for all operators. Novices expressed global satisfaction and device preference for the AWS, whereas experts were indifferent.

Conclusions

AWS-VDL permits faster, easier and more reliable ETI compared to the DLM whatever the previous airway ETI experience and could be a useful device for DLM-ETI learning.

Learning and performance of endotracheal intubation by paramedical students: Comparison of GlideScope(®) and intubating laryngeal mask airway with direct laryngoscopy in manikins

Background and Aims:

GlideScope video laryngoscope (GVL) and intubating laryngeal mask airway (I-LMA) may be used to facilitate intubation and secure the airway in patients with normal and abnormal airways. The aim of this study was to evaluate whether (GVL) and (I-LMA) facilitate and improve the tracheal intubation success rate and could be learned and performed easily by paramedic students when compared with Macintosh direct laryngoscopy (DL).

Methods:

This study was a prospective, randomised crossover trial that included 100 paramedic students. Macintosh DL, I-LMA and GVL were tested in both normal and difficult airway scenarios. Each participant was allowed up to three intubation attempts with each device, in each scenario. The time required to perform tracheal intubation, the success rate, number of intubation attempts and of optimisation manoeuvres and the severity of dental trauma were recorded. Statistical analysis was performed using Chi-square, one-way ANOVA, or Kruskal-Wallis test as appropriate, followed by post hoc test.

Results:

GVL and I-LMA required less time to successfully perform tracheal intubation, showed a greater success rate of intubation, reduced the number of intubation attempts and optimization manoeuvres required and reduced the severity of dental trauma compared to Macintosh DL in both normal and difficult airway scenarios.

Conclusion:

GVL and I-LMA provide better airway management than Macintosh DL in both normal and difficult airway scenarios.

Comparison of the force applied on oral structures during intubation attempts by novice physicians between the Macintosh direct laryngoscope, Airway Scope and C-MAC PM: a high-fidelity simulator-based study

OBJECTIVE

We examined whether the use of Airway Scope (AWS) and C-MAC PM (C-MAC) decreased the force applied on oral structures during intubation attempts as compared with the force applied with the use of Macintosh direct laryngoscope (DL).

DESIGN

Prospective cross-over study.

PARTICIPANTS

A total of 35 novice physicians participated.

INTERVENTIONS

We used 6 simulation scenarios based on the difficulty of intubation and intubation devices.

OUTCOME MEASURES

Our primary outcome measures were the maximum force applied on the maxillary incisors and tongue during intubation attempts, measured by a high-fidelity simulator.

RESULTS

The maximum force applied on maxillary incisors was higher with the use of the C-MAC than with the DL and AWS in the normal airway scenario (DL, 26 Newton (N); AWS, 18 N; C-MAC, 52 N; p<0.01) and the difficult airway scenario (DL, 42 N; AWS, 24 N; C-MAC, 68 N; p<0.01). In contrast, the maximum force applied on the tongue was higher with the use of the DL than with the AWS and C-MAC in both airway scenarios (DL, 16 N; AWS, 1 N; C-MAC, 7 N; p<0.01 in the normal airway scenario; DL, 12 N; AWS, 4 N; C-MAC, 7 N; p<0.01 in the difficult airway scenario).

CONCLUSIONS

The use of C-MAC, compared with the DL and AWS, was associated with the higher maximum force applied on maxillary incisors during intubation attempts. In contrast, the use of video laryngoscopes was associated with the lower force applied on the tongue in both airway scenarios, compared with the DL. Our study was a simulation-based study, and further research on living patients would be warranted.

[A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin]

OBJECTIVE

Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios.

METHODS

Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway.

RESULTS

Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001).

CONCLUSION

In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

Comparison between bougies and stylets for simulated tracheal intubation with the C-MAC D-blade videolaryngoscope

BACKGROUND

The C-MAC D-blade is a new, highly angulated, videolaryngoscope blade designed for use in patients with difficult airways. Directing a tracheal tube into the trachea with any indirect viewing laryngoscope can be difficult, even with a good view of the laryngeal inlet.

OBJECTIVE

To determine which introducing strategy is most suitable for use with the C-MAC D-blade videolaryngoscope.

DESIGN

Observational manikin study.

SETTING

Centre for Simulation and Patient Safety.

PARTICIPANTS

Twenty-four anaesthetists of at least 12 months' of experience.

INTERVENTIONS

Six tracheal tube introducer strategies (no tracheal tube introducer (TX); hockey stick stylet (SH); Gliderite stylet (SG); bougie with tube loaded distally, near its curved tip (BD); bougie with tube loaded proximally (BP); bougie unloaded until tracheal placement (BU)) for each of two laryngoscopy settings (easy and difficult) in a SimMan 3G manikin. Two intubation attempts, with a maximum time allowance of 60 s each, were allowed for all laryngoscopy setting/introducer combinations.

MAIN OUTCOME MEASURES

Time to intubate in seconds. Secondary outcome was overall subjective difficulty using a visual analogue scale.

RESULTS

In the easy laryngoscopy setting, time to intubation was [median (interquartile range): SH 8.5 sec (7 to 11); SG 10 (8 to 11.5); BD 11 (10 to 12.5); TX 11 (7 to 31.5); BP 12 (11 to 13.5); BU 13 (11 to 14.5). There was no evidence of an overall difference in introducer strategies for time to intubate (P <  .025) with SG and SH found to be favourable when compared with BU, and SH was also favourable when compared with BP. In the difficult laryngoscopy setting, time to intubation was: SG 11.5 (10 to 17.5); SH 14 (12 to 22); BD 15.5 (12 to 23.5); BU 16.5 (14 to 21); BP 16.5 (15.5 to 20.5); TX 60 (26.5 to 60). There was evidence of an overall difference in introducer strategies for time to intubate (P < 0.025) with all introducers found to be favourable compared with TX. SG was found to be favourable when compared with BU and BP. In groups TX and SH, anaesthetists failed to intubate in 13 of 24 cases and 1 of 24 cases, respectively. The visual analogue scores tended to reflect intubation times, more so in the difficult setting.

CONCLUSION

The differences in time to intubate in both the easy and difficult laryngoscopy settings were minor for the different introducer strategies studied. The stylet introducers tended to take less time, but this did not result in important statistical differences. When using the C-MAC D-blade videolaryngoscope for simulated tracheal intubation, stylets and bougies performed in a similar fashion.

Defining the learning curve for endotracheal intubation using direct laryngoscopy: A systematic review

More than two failed intubation attempts and failed endotracheal intubations (ETIs) are associated with severe complications and death. The aim of this review was to determine the number of ETIs a health care provider in training needs to perform to achieve proficiency within two attempts. A systematic search of the literature was conducted covering the time frame of January 1990 through July 2014. We identified 13 studies with a total of 1462 students who had attempted to intubate 19,108 patients. This review shows that in mostly elective circumstances, at least 50 ETIs with no more than two intubation attempts need to be performed to reach a success rate of at least 90%. However, the evidence is heterogeneous, and the incidence of difficult airways in non-elective settings is up to 20 times higher compared to elective settings. Taking this factor into account, training should include a variety of exposures and should probably exceed 50 ETIs to successfully serve the most vulnerable patients.

A randomised crossover trial comparing the Airtraq(®) NT, McGrath(®) MAC and Macintosh laryngoscopes for nasotracheal intubation of simulated easy and difficult airways in a manikin

OBJECTIVE

Several devices can aid nasotracheal intubation when managing difficult airways. The McGrath MAC and Airtraq NT were compared with a Macintosh laryngoscope when studying the performance of anaesthetists with different levels of experience, in a manikin model of easy or difficult airway scenarios.

METHODS

Sixty-three anaesthetists were recruited into a randomised trial in which each performed nasotracheal intubation with all laryngoscopes, in both scenarios. The main endpoint was intubation time. Additional endpoints included laryngoscopic view, intubation success, number of optimisation manoeuvres, audible dental clicks and the force applied to the upper airway.

RESULTS

Intubation time was significantly shorter using the McGrath MAC in both scenarios and using the Airtraq in the difficult scenario, when compared with the Macintosh laryngoscope. Both devices gave more Cormack and Lehane grade 1 or 2 views than the Macintosh in the difficult scenario (p<0.001). The McGrath MAC had the best first-attempt success rate (98.4% vs. 96.8% and 95.8%, p<0.001 for the Airtraq NT and Macintosh laryngoscopes respectively). The number of optimisation manoeuvres, audible dental clicks and subjective assessment of the degree of force applied were significantly lower for indirect laryngoscopes versus the Macintosh laryngoscope (p<0.001).

CONCLUSION

In a manikin, the Airtraq and the McGrath laryngoscopes appeared superior to the Macintosh laryngoscope when dealing with simulated airway scenarios. Both devices were associated with better views, intubation times and rates of success, especially in a simulated "difficult airway". Overall satisfaction was highest with the McGrath laryngoscope. Similar clinical studies are needed.

Performance of intubation with 4 different airway devices by unskilled rescuers: manikin study

INTRODUCTION

This study was designed to compare the performances of 4 airway devices in achieving successful ventilation.

METHODS

A randomized crossover trial was conducted to evaluate 4 airway devices: laryngeal mask airway (LMA), i-gel (iGEL), PENTAX Airway Scope (AWS), and Macintosh laryngoscope (MCL). Thirty-eight unskilled rescuers performed intubation on a manikin during chest compressions in normal and difficult airway scenarios. The time to ventilation, intubation success rate, and difficulty of intubation were measured.

RESULTS

The time to ventilation of the airway devices in the normal scenario had a median value of 8.8 seconds (interquartile range, 7.3-10.5 seconds) for iGEL, 16.1 seconds (13.9-19.3 seconds) for LMA, 30.6 seconds (24.6-37.6 seconds) for AWS, and 35.0 seconds (29.5-45.9 seconds) for MCL. In the difficult airway scenario, the respective time to ventilation was 8.6 seconds (7.8-10.0 seconds), 15.3 seconds (14.3-20.2 seconds), 29.4 seconds (25.7-36.3 seconds) and 59.0 seconds (46.1-103.3 seconds). The success rates were 100% and 100% for LMA, 100% and 100% for iGEL, 97.4% and 94.7% for AWS, and 78.9% and 47.4% for MCL in the normal and difficult airway scenarios. The difficulties of intubation expressed as numerical rating scale were 2.0 and 2.0 (median values) for LMA, 1.0 and 2.0 for iGEL, 3.0 and 3.0 for AWS, and 4.0 and 5.0 for MCL in the normal and difficult airway scenarios, respectively.

CONCLUSION

With novice intubators who were unfamiliar with the airway devices, the LMA, iGEL, and AWS were superior to the MCL for establishing an airway without interruption of chest compressions in a manikin study. Intubation with the iGEL was faster and easier than with the other airway devices.

A comparison of the force applied on oral structures during intubation attempts between the Pentax-AWS airwayscope and the Macintosh laryngoscope: a high-fidelity simulator-based study

OBJECTIVE

We sought to determine whether the use of Pentax-AWS Airwayscope (AWS) applied less force on oral structures during intubation attempts than a conventional direct laryngoscope (DL).

DESIGN

Prospective cross-over study.

PARTICIPANTS

A total of 37 physicians (9 transitional-year residents, 20 emergency medicine residents and 8 emergency physicians) were enrolled.

INTERVENTIONS

We used four simulation scenarios according to the difficulty of intubation and devices and used a high-fidelity simulator to quantify the forces applied on the oral structures.

OUTCOME MEASURES

Primary outcomes were the maximum force applied on the maxillary incisors and tongue. Other outcomes of interest were time to intubation and glottic view during intubation attempts.

RESULTS

The maximum force applied on the maxillary incisors in the normal airway scenario was higher with the use of AWS than that with DL (107 newton (N) vs 77 N, p=0.02). By contrast, the force in the difficult airway scenario was significantly lower with the use of AWS than that of the DL (89 N vs 183 N, p<0.01). Likewise, the force applied on the tongue was significantly lower with the use of AWS than the use of DL in both airway scenarios (11 N vs 27 N, p<0.001 in the normal airway scenario; 12 N vs 40 N, p<0.01 in the difficult airway scenario).

CONCLUSIONS

The use of AWS during intubation attempts was associated with decreased forces applied to oral structures in the simulated difficult airway scenario.

Comparison of the C-MAC D-Blade, Conventional C-MAC, and Macintosh Laryngoscopes in Simulated Easy and Difficult Airways

OBJECTIVE

Recently, to further enhance the potential in the management of difficult airways, the highly angulated D-Blade was added to the C-MAC system. The purpose of this study was to investigate the laryngoscopic view and intubation parameters using the new C-MAC D-Blade in comparison to the conventional C-MAC video laryngoscope and Macintosh direct laryngoscope in simulated easy and difficult airways.

METHODS

We recruited 26 experienced anaesthesia providers into a randomized trial. Each performed tracheal intubation of a Laerdal SimMan(®) manikin with each laryngoscope in the following laryngoscopy scenarios: (1) normal airway, (2) cervical spine immobilization, and (3) tongue edema. The intubation times, success rates, number of intubation attempts, laryngoscopic views, and severity of dental compression were recorded.

RESULTS

In all scenarios, video laryngoscopes provided better laryngeal exposure than the ML and appeared to produce less dental pressure. In the cervical spine immobilization scenario, D-Blade caused less dental pressure and showed better Cormack-Lehane (CL) classes than the other devices (p<0.001). There were no differences between video laryngoscopes in success of tracheal intubation (p>0.05). The CMAC provided the most rapid intubation. The rate of failure was 19% with ML. In the tongue edema scenario, the CMAC provided the most rapid and successful intubation (p<0.001). There were no differences between video laryngoscopes in laryngoscopic views according to CL classification and dental pressure (p>0.05). The rate of failure was 46% with the ML and 7% with the D-Blade.

CONCLUSION

The CMAC D-Blade caused less dental pressure than the conventional C-MAC and ML in the cervical immobilization scenario. The conventional CMAC performed better than the D-Blade and ML in the tongue edema scenario. These two video laryngoscopes may complement each other in various difficult airway situations.

Pentax Airway Scope® vs Macintosh laryngoscope for tracheal intubation in adult patients: a systematic review and meta-analysis

The Pentax Airway Scope(®) is a single-use optical videolaryngoscope designed to assist with difficult tracheal intubation. We systematically reviewed the efficacy of the Pentax Airway Scope with that of a conventional laryngoscope for tracheal intubation in adults with 'normal' and 'difficult' airways. We included 17 randomised controlled trials with a total of 1801 participants. We used the DerSimonian and Laird random-effects model to calculate pooled relative risk or weighted mean differences. The relative risk (95% CI) of a Cormack-Lehane grade-1 laryngeal view was 2.40 (1.76-2.49) with the Pentax Airway Scope compared with the Macintosh laryngoscope, p < 0.00001. We found no other differences between the two laryngoscopes. Despite a superior laryngeal view, the Pentax Airway Scope provides little clinical benefit over the conventional laryngoscope.

Learning curves of macintosh laryngoscope in nurse anesthetist trainees using cumulative sum method

Background. Tracheal intubation is a potentially life-saving procedure. This skill is taught to many anesthetic healthcare professionals, including nurse anesthetists. Our goal was to evaluate the learning ability of nurse anesthetist trainees in their performance of orotracheal intubation with the Macintosh laryngoscope. Methods. Eleven nurse anesthetist trainees were enrolled in the study during the first three months of their training. All trainees attended formal lectures and practice sessions with manikins at least one time on performing successful tracheal intubation under supervision of anesthesiology staff. Learning curves for each nurse anesthetist trainee were constructed with the standard cumulative summation (cusum) methods. Results. Tracheal intubation was attempted on 388 patients. Three hundred and six patients (78.9%) were successfully intubated on the trainees' first attempt and 17 patients (4.4%) on the second attempt. The mean ± SD number of orotracheal intubations per trainee was 35.5 ± 5.1 (range 30-47). Ten (90.9%) of 11 trainees crossed the 20% acceptable failure rate line. A median of 22 procedures was required to achieve an 80% orotracheal intubations success rate. Conclusion. At least 22 procedures were required to reach an 80% success rate for orotracheal intubation using Macintosh laryngoscope in nonexperienced nurse anesthetist trainees.

Utilization of exploration-based learning and video-assisted learning to teach GlideScope videolaryngoscopy

BACKGROUND

GlideScope (GS) is used in pediatric endotracheal intubation (ETI) but requires a different technique compared to direct laryngoscopy (DL).

PURPOSES

This article was written to evaluate the efficacy of exploration-based learning on procedural performance using GS for ETI of simulated pediatric airways and establish baseline success rates and procedural duration using DL in airway trainers among pediatric providers at various levels.

METHODS

Fifty-five pediatric residents, fellows, and faculty from Pediatric Critical Care, NICU, and Pediatric Emergency Medicine were enrolled. Nine physicians from Pediatric Anesthesia benchmarked expert performance. Participants completed a demographic survey and viewed a video by the GS manufacturer. Subjects spent 15 minutes exploring GS equipment and practicing the intubation procedure. Participants then intubated neonatal, infant, child, and adult airway simulators, using GS and DL, in random order. Time to ETI was recorded.

RESULTS

Procedural performance after exploration-based learning, measured as time to successful ETI, was shorter for DL than for GS for neonatal and child airways at the.05 significance level. Time to ETI in adult airway using DL was correlated with experience level (p =.01). Failure rates were not different among subgroups.

CONCLUSIONS

A brief video and period of exploration-based learning is insufficient for implementing a new technology. Pediatricians at various levels of training intubated simulated airways faster using DL than GS.

Comparison of GlideScope Videolaryngoscopy to Direct Laryngoscopy for Intubation of a Pediatric Simulator by Novice Physicians

Objective. To compare novice clinicians' performance using GlideScope videolaryngoscopy (GVL) to direct laryngoscopy (DL). Methods. This was a prospective, randomized crossover study. Incoming pediatric interns intubated pediatric simulators in four normal and difficult airway scenarios with GVL and DL. Primary outcomes included time to intubation and rate of successful intubation. Interns rated their satisfaction of the devices and chose the preferred device. Results. Twenty-five interns were included. In the normal airway scenario, there were no differences in mean time for intubation with GVL or DL (61.4 versus 67.4 seconds, P = NS) or number of successful intubations (19 versus 18, P = NS). In the difficult airway scenario, interns took longer to intubate with GVL than DL (87.7 versus 61.3 seconds, P = 0.018), but there were no differences in successful intubations (14 versus 15, P = NS). There was a trend towards higher satisfaction for GVL than DL (7.3 versus 6.4, P = NS), and GVL was chosen as the preferred device by a majority of interns (17/25, 68%). Conclusions. For novice clinicians, GVL does not improve time to intubation or intubation success rates in a pediatric simulator model of normal and difficult airway scenarios. Still, these novice clinicians overall preferred GVL.

Comparing the novel GlideScope Groove videolaryngoscope with conventional videolaryngoscopy: a randomized mannequin study of novice providers

STUDY OBJECTIVE

To compare the GlideScope Groove (GG) with conventional GlideScope videolaryngoscopy (GVL) and direct laryngoscopy (DL) on intubation times, intubation attempts, and glottic visualization of an airway mannequin by medical students.

DESIGN

Randomized crossover trial.

SETTING

Intensive care unit of an academic tertiary-care hospital.

PARTICIPANTS

34 medical students with no airway management experience.

MEASUREMENTS

Each participant received standardized video instruction on all three laryngoscopes and was given 10 minutes to practice with each device. The participants had two attempts using DL, and then had two attempts each with either the GG or GVL in random order.

MEASUREMENTS

Time-to-intubate the mannequin in seconds was recorded. Secondary outcomes were Cormack-Lehane grade and number of intubation attempts, also recorded.

MAIN RESULTS

The median number of seconds required to successfully intubate the mannequin with DL, GVL, and GG were 17.4 seconds [interquartile range (IQR) 13.2 - 22.1)], 17.7 seconds (IQR 14.9 - 21.0), and 21.7 seconds (IQR 15.4 - 37.0), respectively. No differences in time-to-intubate was noted among the three devices (P = 0.45). A Cormack-Lehane grade 1 view was obtained for 25 of 34 participants (74%) with DL, 32 of 34 participants (94%) with GVL, and 34 of 34 participants (100%) with GG. First-attempt intubation success was 30 of 34 participants (88%) with DL, 34 of 34 participants (100%) with GVL, and 11 of 34 participants (32%) with GG. Using the GG, 6 of 24 participants (18%) required three attempts. More attempts were required for the GG than for DL (P < 0.001) or GVL (P < 0.001).

CONCLUSIONS

GG was not superior to DL or GVL in time-to-intubate an airway mannequin.

Parker Flex-It intubation stylet versus a 90-degree curved stylet during intubation with the McGrath videolaryngoscope performed by novices: a manikin study with 5 airway scenarios

STUDY OBJECTIVE

To compare the Parker Flex-It intubation stylet with a 90-degree curved stylet using the McGrath videolaryngoscope in 5 airway scenarios (from easy to difficult) in a manikin.

DESIGN

Prospective, randomized study.

SETTING

Academic hospital.

SUBJECTS

20 staff anesthesiologists with no previous experience in videolaryngoscopy.

MEASUREMENTS

Subjects performed a total of 200 intubations with the McGrath Series 5 videolaryngoscope and completed a questionnaire afterwards.

RESULTS

Overall success rate was significantly higher with the Parker Flex-It intubation stylet (96 successful intubations with the Parker Flex-It vs 79 intubations in the 90° curved stylet group; P < 0.05). Intubation time was not significantly different. Subjects rated the Parker Flex-It intubation stylet as the better device for intubation with the McGrath videolaryngoscope in routine or emergency situations.

CONCLUSION

Intubation of the manikin with the McGrath videolaryngoscope had more success with the Parker Flex-It intubation stylet than a 90° curved stylet.

A comparison of the AMBU ISCOPE and Macintosh laryngoscopes: first experience with a new device for tracheal intubation: a manikin study

CONTEXT

Video laryngoscopes achieve laryngeal visualisation through indirect imaging using video cameras that look around the curve of the tongue. The new AMBU ISCOPE intubation device combines features from the laryngeal mask airway with video laryngoscopy enabling visual control of tracheal intubation without the use of a stylet.

OBJECTIVE

We hypothesised that the AMBU ISCOPE would shorten the time taken to intubate a manikin compared to the Macintosh laryngoscope.

DESIGN

Crossover study.

SETTING

University hospital in Denmark.

STUDY PERIOD

April 2011.

PARTICIPANTS

We enrolled 36 trainees (19 nurse anaesthetists and 17 anaesthetists) with a median of 7 months of experience in anaesthesia (interquartile range 5 to 7.5 months).

INTERVENTION

Tracheal intubation of a manikin, the Laerdal Airway Management Trainer, using either the AMBU ISCOPE, a new intubation conduit, or a conventional Macintosh laryngoscope. Every trainee performed three tracheal intubations with each device.

MAIN OUTCOME MEASURES

The primary end-point was time to intubation. Secondary end-points were Cormack & Lehane grade and dental contact.

RESULTS

Median time to tracheal intubation was 33.5 s using a Macintosh laryngoscope and 41.5 s using the AMBU ISCOPE device (P = 0.008). In both groups, 97% of intubations were successful. Ninety-seven percent of laryngeal visualisations achieved using the AMBU ISCOPE device were reported to be Cormack & Lehane grade 1 versus 57% for the Macintosh laryngoscope (P = 0.0001).

CONCLUSION

Tracheal intubation time was significantly longer in trainees using the AMBU ISCOPE intubation device compared to a Macintosh laryngoscope, but with a difference of only 8 s. Laryngeal visualisation was significantly better using the AMBU ISCOPE device, but success rates for intubation were the same.

Telebation: next-generation telemedicine in remote airway management using current wireless technologies

INTRODUCTION

Since the first remote intubation with telemedicine guidance, wireless technology has advanced to enable more portable methods of telemedicine involvement in remote airway management.

MATERIALS AND METHODS

Three voice over Internet protocol (VoIP) services were evaluated for quality of image transmitted, data lag, and audio quality with remotely observed and assisted intubations in an academic emergency department. The VoIP clients evaluated were Apple (Cupertino, CA) FaceTime(®), Skype™ (a division of Microsoft, Luxembourg City, Luxembourg), and Tango(®) (TangoMe, Palo Alto, CA). Each client was tested over a Wi-Fi network as well as cellular third generation (3G) (Skype and Tango).

RESULTS

All three VoIP clients provided acceptable image and audio quality. There is a significant data lag in image transmission and quality when VoIP clients are used over cellular broadband (3G) compared with Wi-Fi.

CONCLUSIONS

Portable remote telemedicine guidance is possible with newer technology devices such as a smartphone or tablet, as well as VoIP clients used over Wi-Fi or cellular broadband.

Comparison of 3 video laryngoscopes with the Macintosh in a manikin with easy and difficult simulated airways

OBJECTIVES

Tracheal intubation is used to maintain a patent airway and can occasionally be difficult in a potentially difficult airway, especially for novice managers. In this study, we evaluated the time required, extent of the difficulty, and number of dental clicks in the tracheal intubation for novice medical students between the Macintosh (Truphatek International Ltd, Netanya, Israel) and 3 video laryngoscopes in normal and difficult simulated intubation positions on manikins on both the table and floor.

METHODS

We recruited 20 medical students as novice airway managers. They used the Macintosh, Truview (Truphatek International Ltd, Netanya, Israel), Glidescope (Verathon Inc., Bothell, WA), and Airway Scope (AWS) (Pentax Corporation, Tokyo, Japan) laryngoscopes in normal and difficult simulated airways on manikins on both the table and floor. The time to intubate, modified Cormack-Lehane score, intubation difficulty score, and dental click number were estimated and compared.

RESULTS

All 20 medical students completed the study. The AWS required the shortest intubation time, provided the best glottic view and easiest intubation, and resulted in less dental clicks compared with the other 3 laryngoscopes; these phenomena were particularly prominent in the cervical-spine immobilization position on the floor. Although all video laryngoscopes provided better glottic views than the Macintosh laryngoscopy in terms of time to intubate, intubation difficulty score, and the number of dental clicks, the outcomes from the Macintosh laryngoscope were better than those of the Truview and Glidescope.

CONCLUSIONS

The AWS may have the potential for quicker, easier, and safer tracheal intubation in scenarios involving difficult airways for a novice airway manager.

Comparison of GlideScope(®) versus Macintosh laryngoscope for the removal of a hypopharyngeal foreign body: a randomized cross-over cadaver study

OBJECTIVE

This study aimed to evaluate whether GlideScope(®) is an effective and acceptable method for the removal of a hypopharyngeal foreign body.

METHODS

This was a prospective study conducted in 28 first year emergency residents with little prior airway management experience. Participants extracted hypopharyngeal foreign bodies using a Macintosh laryngoscope and GlideScope(®) with Magill and Sponge forceps. The primary endpoints were extraction time and success rate with each device. Participant preferences were also assessed.

RESULTS

The cumulative success rate in relation to time to extraction was significantly higher with the Macintosh laryngoscope than with the GlideScope(®) (p<0.001) regardless of the extraction device. Significantly fewer attempts were required for the first successful extraction with the Macintosh laryngoscope versus GlideScope(®) with Magill forceps (p=<0.001) and Sponge forceps (p=<0.001). The time for successful foreign body extraction using GlideScope(®) was significantly lower when using Magill (median 46 s, IQR 28-75 s) forceps than Sponge forceps (median 79 s, IQR 41-88 s).

CONCLUSIONS

In this cadaver model, the Macintosh laryngoscope appeared to be more efficient and preferred than GlideScope(®) for extracting hypopharyngeal airway foreign bodies that are associated with fatal asphyxiation.

Force and pressure distribution using Macintosh and GlideScope laryngoscopes in normal and difficult airways: a manikin study

BACKGROUND

The forces applied to the soft tissues of the upper airway may have a deleterious effect. This study was designed to evaluate the performance of the GlideScope compared with the Macintosh laryngoscope.

METHODS

Twenty anaesthetists and 20 trainees attempted tracheal intubation of a Laerdal SimMan manikin. Forces and pressure distribution applied by both laryngoscope blades onto the soft upper airway tissues were measured using film pressure transducers. The minimal force needed to achieve a successful intubation, in the same simulated scenario, was measured; additionally, we considered the visualization score achieved by using the Cormack-Lehane grades.

RESULTS

All participants applied, on average, lower force with the GlideScope than with the Macintosh in each simulated scenario. Forces [mean (sd)] applied in the normal airway scenario [anaesthetists: Macintosh 39 (22) N and GlideScope 27 (15) N; trainees: Macintosh 45 (24) N and GlideScope 21 (15) N] were lower than forces applied in the difficult airway scenario [anaesthetists: Macintosh 95 (22) N and GlideScope 66 (20) N; trainees: Macintosh 100 (38) N and GlideScope 48 (16) N]. All the intubations using the GlideScope were successful, regardless of the scenario and previous intubation experience. The average pressure on the blades was 0.13 MPa for the Macintosh and 0.07 MPa for the GlideScope, showing a higher uniformity for the latter.

CONCLUSIONS

The GlideScope allowed the participants to obtain a successful intubation applying a lower force. A flatter and more uniform pressure distribution, a higher successful rate, and a better glottic view were observed with the GlideScope.

Tracheal intubation in the emergency department: a comparison of GlideScope® video laryngoscopy to direct laryngoscopy in 822 intubations

BACKGROUND

Video laryngoscopy has, in recent years, become more available to emergency physicians. However, little research has been conducted to compare their success to conventional direct laryngoscopy.

OBJECTIVES

To compare the success rates of GlideScope(®) (Verathon Inc., Bothell, WA) videolaryngoscopy (GVL) with direct laryngoscopy (DL) for emergency department (ED) intubations.

METHODS

This was a 24-month retrospective observational study of all patients intubated in a single academic ED with a level I trauma center. Structured data forms were completed after each intubation and entered into a continuous quality improvement database. All patients intubated in the ED with either the GlideScope(®) standard, Cobalt, Ranger, or traditional Macintosh or Miller laryngoscopes were included. All patients intubated before arrival were excluded. Primary analysis evaluated overall and first-attempt success rates, operator experience level, performance characteristics of GVL, complications, and reasons for failure.

RESULTS

There were 943 patients intubated during the study period; 120 were excluded due to alternative management strategies. DL was used in 583 (62%) patients, and GVL in 360 (38%). GVL had higher first-attempt success (75%, p = 0.03); DL had a higher success rate when more than one attempt was required (57%, p = 0.003). The devices had statistically equivalent overall success rates. GVL had fewer esophageal intubations (n = 1) than DL (n = 18); p = 0.005.

CONCLUSION

The two techniques performed equivalently overall, however, GVL had a higher overall success rate, and lower number of esophageal complications. In the setting of ED intubations, GVL offers an excellent option to maximize first-attempt success for airway management.

Validation of a model of graded difficulty in Laerdal SimMan: functional comparisons between Macintosh, Truview EVO2, Glidescope Video Laryngoscope and Airtraq

BACKGROUND AND OBJECTIVE

A randomised, cross-over study was designed to validate a new model of graded difficulty (based on mandibular space reduction) in the Laerdal 'SimMan' mannnequin and to suggest functional comparisons between Macintosh. Glidescope Video Laryngoscope, Truview EVO2 and Airtraq.

METHODS

Twenty anaesthetists attempted intubation with all four laryngoscopes in three settings: easy, intermediate (based on a custom-made removable prosthetic insert) and difficult ('tongue oedema', a mannnequin feature). Laryngoscopic view and time to intubate were the primary outcome measures. Other measures were successful intubation, ease of laryngoscopy [visual analogue scale (VAS)] and intubation (VAS), tongue compression score and number of attempts.

RESULTS

Between settings comparisons demonstrated that Macintosh, Glidescope and Airtraq had worsening scores from easy to intermediate with lesser changes for Truview. However, with the intermediate to difficult comparison, Airtraq was the only blade with no worsening of scores. Within-blade comparisons showed that Macintosh was superior over all in both the easy and intermediate settings, whereas Airtraq was the most successful blade in the difficult setting.

CONCLUSION

Our study suggests that Glidescope and, to some extent Truview, are functionally similar to Macintosh and suffer from similar limitations in the difficult setting. On the contrary, Airtraq was functionally unique in providing good laryngeal exposure in the difficult setting and without excessive tongue compression.

A randomized comparison of the GlideScope videolaryngoscope to the standard laryngoscopy for intubation by pediatric residents in simulated easy and difficult infant airway scenarios

BACKGROUND

Videolaryngoscopy has been developed mainly to assist difficult airway intubation. However, there is a lack of studies demonstrating the real efficacy of its use in children. In this study, we tested the hypothesis that GlideScope (Verathon Inc, Bothell, Wash) videolaryngoscope improves tracheal intubation when used by pediatric residents in an advanced patient simulation model.

METHODS

Pediatric residents who passed a pediatric advanced life support course were eligible for the study. An advanced infant simulator was used, and 4 scenarios were proposed: normal airway (NA), tongue edema (TE), tongue edema and oropharyngeal edema, and cervical collar. No participant had prior experience with any videolaryngoscope. After a brief instruction in GlideScope technique, each participant performed the 4 scenarios using both the standard Miller and GlideScope laryngoscopes, in a random sequence.

RESULTS

Sixteen residents were included. The number of failed intubations was higher with GlideScope in NA and TE scenarios (3 vs 0, in both cases). Mean (SD) time to successful intubation was significantly longer with GlideScope in the NA scenario (GlideScope, 38 [SD, 13] vs Miller, 26 [SD, 16] seconds; P = 0.043). The number of maneuvers was significantly higher with GlideScope in the tongue edema and oropharyngeal edema scenario (2.3 [SD, 1.5] vs 1.5 [SD, 1]; P = 0.04). Upper jaw injury index was significantly lower with GlideScope in NA (2.0 [SD, 1] vs 2.6 [SD, 0.8]; P = 0.008) and cervical collar (2.1 [SD, 1.0] vs 2.8 [SD, 0.5]; P = 0.011) scenarios. Participants considered GlideScope technique more difficult than standard Miller in NA (5 [SD, 2.0] vs 3 [SD, 1.3]; P = 0.04) and TE (5.9 [SD, 2.5] vs 3.9 [SD, 1.7]; P = 0.02) scenarios.

CONCLUSIONS

In simulated scenarios of infant NA and difficult airway, when used by pediatric residents, GlideScope did not improve intubation performance when compared with the standard laryngoscope. Nevertheless, GlideScope may be safer for upper jaw injury and could have advantages in the management of complicated airway. Further studies are needed to assess if specific training will improve GlideScope intubation performance and whether the "in simulator" results translate into clinical practice.

Cormack-Lehane classification revisited

BACKGROUND

The Cormack-Lehane (CL) classification is broadly used to describe laryngeal view during direct laryngoscopy. This classification, however, has been validated by only a few studies reporting inconclusive data concerning its reliability. This discrepancy between widespread use and limited evidence prompted us to investigate the knowledge about the classification among anaesthesiologists and its intra- and inter-observer reliability.

METHODS

One hundred and twenty interviews were performed at a major European anaesthesia congress. Participants were interviewed about their general knowledge on grading systems to classify laryngeal view during laryngoscopy and were subsequently asked to define the grades of the CL classification. Inter- and intra-observer reliabilities were tested in 20 anaesthesiologists well familiar with the CL classification, who performed 100 laryngoscopies in a full-scale patient simulator.

RESULTS

Although 89% of interviewed subjects claimed to know a classification to describe laryngeal view during laryngoscopy, 53% were able to name a classification. When specifically asked about the CL classification, 74% of the interviewed subjects stated to know this classification, whereas 25% could define all four grades correctly. In the simulator-based part of the study, inter-observer reliability was fair with a kappa coefficient of 0.35 and intra-observer reliability was poor with a kappa of 0.15.

CONCLUSIONS

The CL classification is poorly known in detail among anaesthesiologists and reproducibility even in subjects well familiar with this classification is limited.

The clinical effectiveness of the streamlined liner of pharyngeal airway (SLIPA) compared with the laryngeal mask airway ProSeal during general anesthesia

Background

The aim of this study was to compare the streamlined liner of the pharynx airway (SLIPA), a new supraglottic airway device (SGA), with the laryngeal mask airway ProSeal™ (PLMA) during general anesthesia.

Methods

Sixty patients were randomly allocated to two groups; a PLMA group (n = 30) or a SLIPA group (n = 30). Ease of use, first insertion success rate, hemodynamic responses to insertion, ventilatory efficiency and positioning confirmed by fiberoptic bronchoscopy were assessed. Lung mechanics data were collected with side stream spirometry at 10 minutes after insertion. We also compared the incidence of blood stain, incidence and severity of postoperative sore throat and other complications.

Results

First attempt success rates were 93.3% and 73.3%, and mean insertion time was 7.3 sec and 10.5 sec in PLMA and SLIPA. There was a significant rise in all of hemodynamic response from the pre-insertion value at one minute following insertion of SLIPA. But, insertion of PLMA was no significant rise in hemodynamic response. There was no statistically significant difference in the mean maximum sealing pressure, gas leakage, lung mechanics data, gastric distension, postoperative sore throat and other complication between the two groups. Blood stain were noted on the surface of the device in 40% (n = 12) in the SLIPA vs. 6.7% (n = 2) in the PLMA.

Conclusions

The SLIPA is a useful alternative to the PLMA and have comparable efficacy and complication rates. If we acquire the skill to use, SLIPA may be considered as primary SGA devices during surgery under general anesthesia.

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.