Comparison of the Glidescope, the McGrath, the Airtraq and the Macintosh laryngoscopes in simulated difficult airways*

Comparison of Intubation Conditions Between Airtraq, McGrath Video Laryngoscopes, and Macintosh Under Conditions of Simulated Trauma Airway and Rapid Sequence Induction Intubation

BACKGROUND

Patients arriving at the emergency department with a potential cervical spine injury and immobilized in a rigid cervical collar often require emergency airway management and rapid sequence induction intubation (RSII). There have been several advances in airway management with the advent of channeled (Airtraq^Ⓡ; Prodol Meditec) and nonchanneled (McGrath^Ⓡ; Meditronics) video laryngoscopes, which enable intubation without the removal of the cervical collar, but their efficacy and superiority over conventional laryngoscopy (Macintosh) in the presence of a rigid cervical collar and cricoid pressure have not been evaluated.

OBJECTIVE

Our aim was to compare the channeled (Airtraq [group A]) and nonchanneled (McGrath [Group M]) video laryngoscopes with a conventional laryngoscope (Macintosh [Group C]) in a simulated trauma airway.

METHODS

A prospective randomized controlled study was conducted in a tertiary care center. Participants were 300 patients requiring general anesthesia (American Society of Anesthesiologists class I or II), of both sexes, and aged 18-60 years. Airway management was simulated without removal of a rigid cervical collar and using cricoid pressure during intubation. After RSI, patients were intubated with one of the study techniques according to randomization. Intubation time and intubation difficulty scale (IDS) score were noted.

RESULTS

Mean intubation time was 42.2 s in group C, 35.7 s in group M, and 21.8 s in group A (p = 0.001). Intubation was easy in group M and group A (median IDS score of 0; interquartile range [IQR] 0-1 for group M and median IDS score of 1; IQR 0-2 for group A and group C; p < 0.001). A higher proportion (95.1%) of patients had an IDS score of < 1 in group A.

CONCLUSIONS

The performance of RSII with cricoid pressure in the presence of a cervical collar was easier and more rapid with channeled video laryngoscope than with other techniques.

A Comparison of McGrath Videolaryngoscope versus Macintosh Laryngoscope for Nasotracheal Intubation: A Systematic Review and Meta-Analysis

Background: In this study, it was shown that the routine use of McGrath videolaryngoscopy may improve intubation success rates. The benefits to using a videolaryngoscope in nasotracheal intubation were also demonstrated. However, no solid evidence concerning the effectiveness of the use of McGrath videolaryngoscopes in nasotracheal intubation has previously been reported. As a result, we questioned whether, in adult patients who underwent oral and maxillofacial surgeries with nasotracheal intubation (P), the use of a McGrath videolaryngoscope (I) compared with a Macintosh laryngoscope (C) could reduce the intubation time, improve glottis visualization to a score of classification 1 in the Cormack–Lehane classification system, and improve the first-attempt success rate (O). The secondary outcomes measured were the rate of the use of Magill forceps and the external laryngeal pressure (BURP) maneuver used. Methods: An extensive literature search was conducted using databases. Only randomized controlled trials that compared the McGrath videolaryngoscopy and Macintosh laryngoscopy techniques in nasotracheal intubation in adult patients were included. Results: Five articles met the inclusion criteria and were included in the final analysis (n = 331 patients). The results showed a significant decrease in intubation time and a higher rate of classification 1 scores in the Cormack–Lehane classification system, but no difference in the first-attempt success rates were found between the McGrath group and the Macintosh group. Decreases in the rate of the use of Magill forceps and the use of the external laryngeal pressure maneuver were also found in the pooled analysis. With regard to the overall risk of bias, the selected trials were classified to have at least a moderate risk of bias, because none of the trials could blind the operator to the type of laryngoscope used. Conclusions: Our analysis suggests that the use of a McGrath videolaryngoscope in nasotracheal intubation resulted in shorter intubation times, improved views of the glottis and similar first-success rates in adult patients who received general anesthesia for dental, oral, maxillofacial, or head and neck cancer surgery, and also reduced the use of Magill forceps and the BURP maneuver.

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.

A Comparative Study in Airway Novices Using King Vision Videolaryngoscope and Conventional Macintosh Direct Laryngoscope for Endotracheal Intubation

Background and Objectives

Tracheal intubation using laryngoscopy is a fundamental skill, for an anesthesiologist. However, teaching this skill is difficult since Macintosh direct laryngoscope (DL) allows only one individual to view the larynx during the procedure. Hence, this study aimed to determine whether King Vision® videolaryngoscope (KVL) provides any advantage over direct laryngoscopy in teaching this skill to airway novices.

Materials and Methods

In this prospective randomized crossover study, Ethical Committee clearance was obtained from the institutional review board (MSRMC/EC/2017) and the study was registered with Clinical Trial Registry. After informed consent, 53 medical students were allotted to perform laryngoscopy and endotracheal intubation on a manikin by using either KVL or Macintosh DL. The participants first performed laryngoscopy with either KVL or Macintosh DL following a brief instruction and then crossed over to the second arm of the study to perform laryngoscopy using the other scope. The primary outcome measure was the time for successful endotracheal intubation. The secondary outcome measures were incidence of esophageal intubation (EI), excess application of pressure on maxillary teeth excess maxillary pressure, and success rate.

Results

Mean time for endotracheal intubation was significantly faster using KVL than in DL (44.64 vs. 87.72 s; P < 0.001). No significant difference was found in the incidence of esophageal intubation 15.1% in KVL group versus 24.5% in DL group (P = 0.223). In the KVL group, 81.1% did not apply pressure on maxillary teeth versus 26.4% in the DL group (P < 0.001). The success rate of intubation was 100% in the KVL group versus 86.8% in the DL group (P = 0.006).

Conclusion

The KVL is a more effective tool to teach endotracheal intubation in comparison to Macintosh laryngoscope in airway novice medical students. Clinical trial registry India registration number: CTRI/2017/11/010491.

A randomized controlled trial comparing nociception level (NOL) index, blood pressure, and heart rate responses to direct laryngoscopy versus videolaryngoscopy for intubation: the NOLint project

PURPOSE

The effect of direct laryngoscopy using a Macintosh blade (MAC) vs GlideScope™ videolaryngoscopy using a Spectrum LoPro blade (GVL) on nociceptive stimulation has not been quantitatively studied. This study used the new nociception level (NOL) index to compare the nociceptive response induced by GVL or MAC during laryngoscopy with or without intubation.

METHODS

Patients underwent two laryngoscopies at four-minute intervals (L1, L2), one with GVL and the other with MAC (first randomization). A third laryngoscopy (L3) followed by tracheal intubation was performed four minutes after L2 (GVL or MAC, second randomization). Nociception was quantitatively assessed by NOL and standard hemodynamic parameters (heart rate [HR] and mean arterial pressure). For the crossover design, blade comparisons accounted for sequence and blade type. A possible carryover effect between laryngoscopies was assessed.

RESULTS

In the 50 patients randomized, there was no carryover effect from one laryngoscopy to the next for all analyzed parameters. Nociception level index peak values were higher with MAC than GVL. Analysis of ΔNOL showed a lower nociceptive response with GVL for L1+L2 combined. Mean peak NOL values were significantly higher after L3+intubation than after L1+L2, for both GVL and MAC groups. Analysis of ΔHR values did not show a significant difference between GVL and MAC for any laryngoscopy.

CONCLUSION

Laryngoscopy alone with GVL induces less nociception than with MAC. The NOL was more sensitive than HR at detecting nociceptive responses to MAC vs GVL. Additionally, and irrespective of which technique/blade was used, the combination of laryngoscopy + tracheal intubation produced a much greater nociceptive response than the laryngoscopy alone.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03277872); registered 29 August 2017.

Face-To-Face Double-Lumen Tube Intubation With the Airtraq Video Laryngoscope for Emergency Thoracic Surgery: A Case Report

Double-lumen intubation is commonly used for thoracic surgery as it allows rapid and effective one-lung ventilation. However, it is more difficult than single-lumen tube intubation, notably in the context of emergency surgery and/or in hypoxemic patients. We report the case of a 57-year-old patient requiring emergency revision surgery after an upper right lobectomy due to postoperative pneumothorax and pleuropneumonia. As rapid lung isolation was required due to a bronchopleural fistula, rapid sequence induction and double-lumen tube intubation were performed. In addition, as the patient was hypoxemic with incomplete pre-oxygenation and too uncomfortable to tolerate the recumbent position despite high-flow oxygen, intubation was performed in face-to-face position. The patient was successfully intubated in 22 seconds and the right lung immediately isolated, allowing the surgeon to clean the pleural cavity. This is the first report of a double-lumen tube intubation in face-to-face position. The expected difficulties related to this type of intubation were successfully prevented using an Airtraq laryngoscope. Although such a strategy cannot be recommended from this one case, this report is encouraging for future studies evaluating the potential advantages of Airtraq use for double-lumen face-to-face intubation for emergency thoracic surgery.

Comparative Evaluation of McGrath MAC, Truview Video Laryngoscopes and Macintosh Laryngoscope for Endotracheal Intubation in Patients Undergoing Surgery under General Anaesthesia

Background:

Videolaryngoscopy is a newly developed technique to improve tracheal intubation success. It was made to bypass the need of directly visualising the glottic inlet. These devices are advantageous as there is no need of aligning the laryngeal, pharyngeal and oral axes for a clear view, thus making intubation easier and faster.

Aim and Objectives:

Primary objective of the study was to determine the duration of laryngoscopy and intubation and Cormack - Lehane grading when intubating with McGrath MAC, Truview video laryngoscope and Macintosh laryngoscope. Secondary objectives of the study were to determine the number of attempts and optimization manouveres required to intubate.

Materials and Methods:

This study was conducted on total of 120 patients in age 20-70 years, either sex, with American Society of Anaesthesiologists physical status classes I or II scheduled for elective surgery under general anaesthesia. They were randomly assigned equally to group 1, 2 and 3 (n = 40) to be intubated by Mcgrath MAC video laryngoscope, Truview video laryngoscope and Macintosh laryngoscope respectively. Parameters recorded were duration of laryngoscopy and intubation, Cormack Lahane grading, ease of intubation, number of attempts and optimisation manouveres required for intubation.

Statistical Analysis:

Comparison of mean value among the three groups was done using student t test and percentage comparison was done using chi square test. To compare more than two variables ANOVA test was used. The P values of less than 0.05 was considered statistically significant.

Results:

Duration of laryngoscopy was significantly less in McGrath MAC group when compared to Truview group (P = 0.02) and to Macintosh group (P < 0.001) and the duration of intubation was comparable among all three study groups (P > 0.05). The difference in Cormack - Lehane grading was not significant between McGgrath MAC and Trueview (P = 0.71) but was significant between McGrath MAC and Macintosh (P = 0.002) and Trueview and Macintosh (P = 0.002). Ease of intubation was better in McGrath MAC and Truview groups compared to Macintosh group (P < 0.05). Intubation was successful in the first attempt in 39 (97.50%) patients in McGrath MAC group, 40 (100%) patients in Truview group and 35 (87.50%) patients in Macintosh group. McGrath MAC and Truview groups performed better with respect to optimization manoeuvres compared to Macintosh group (P < 0.05). Trauma was observed in 2 (5%) patients in Truview group and 5 (12.50%) patients in Macintosh group. In McGrath MAC group, no patient underwent any trauma.

Conclusion:

Although duration of laryngoscopy was significantly shorter in McGrath as compared to Truview video laryngoscope and Macintosh laryngoscope but the duration of intubation was comparable between the three groups. Both these video laryngoscopes performed significantly better than Macintosh laryngoscope with respect to laryngoscopic view, requirement of optimization manoeuvre and need for second attempt for intubation.

Video Assisted Laryngoscope Facilitates Intubation Skill Learning in the Emergency Department

Background

Up-to-date technology has been increasingly useful for learning resuscitation skills in the emergency and resuscitation settings. It improves the learning curve of the learners and helps them to avoid making mistakes on real patients. This study aimed to evaluate the educational efficiency for tracheal intubation by comparing Macintosh (direct) laryngoscope (DL) and video laryngoscope (VL) learning in novices.

Methods

This prospective randomized controlled study was conducted in an emergency department between 2013 and 2014. Fifth- and sixth-year medical students were enrolled and assigned to normal airway and difficult airway groups, respectively. They were then further randomized into using a VL or DL for tracheal intubation learning. Participants had three practices before proceeding to the post-course assessment. Our primary outcome was post-course assessment performance, which included intubation success rate, total intubation time and best glottic view. The secondary outcome was the sum of total intubation learning times during the three practices.

Results

We recruited 177 undergraduate students. Of these, 97 were assigned to the normal airway group (49 VL and 48 DL) and 80 were placed in the difficult airway group (40 each for VL and DL). VL significantly quickened the intubation learning time in both the normal airway and difficult airway groups (140 s vs. 158 s, 141 s vs. 221.5 s; both p < 0.05). The learning curve was much improved with VL when compared using time-to-event analysis (p < 0.001). VL also improved the glottic view performance during post-course assessments.

Conclusions

VL improves the learning curve in acquiring intubation skills compared with traditional DL. It shortens the time undergraduate students take to develop such skills and increased their first attempt success rates.

First-Pass Success Intubations Using Video Laryngoscopy Versus Direct Laryngoscopy: A Retrospective Prehospital Ambulance Service Study

OBJECTIVE

In emergency medicine, endotracheal intubation is the gold standard for airway management. First-pass intubation success is beneficial because it secures the patient airway more quickly and avoids complications associated with repeated attempts, such as bleeding and swelling of soft tissue. The key to first-pass success is the ability to visualize the laryngeal inlet. Visualization can be accomplished using traditional direct laryngoscopy or video laryngoscopy. The purpose of our study was to compare the rate of successful first-pass endotracheal intubations using a video laryngoscope with that using a direct visualization laryngoscope in a prehospital emergency setting.

METHODS

We retrospectively reviewed data that had been prospectively collected in our emergency department regarding patients who underwent endotracheal intubation performed by personnel from a single local ambulance service from January 1, 2014, through December 31, 2015.

RESULTS

One hundred eighty-one patients were intubated using video laryngoscopy and 115 using direct visualization laryngoscopy. The first-pass endotracheal intubation success rate using video laryngoscopy was 12.6% higher than with direct laryngoscopy.

CONCLUSION

This retrospective study shows that video laryngoscopy had a higher first-pass success rate than direct laryngoscopy. This is promising because decreasing failure rates provide better patient outcomes.

Impact of a custom-made 3D printed ergonomic grip for direct laryngoscopy on novice intubation performance in a simulated easy and difficult airway scenario-A manikin study

Direct laryngoscopy using a Macintosh laryngoscope is the most widely used approach; however, this skill is not easy for novices and trainees. We evaluated the performance of novices using a laryngoscope with a three-dimensional (3D)-printed ergonomic grip on an airway manikin. Forty second-year medical students were enrolled. Endotracheal intubation was attempted using a conventional Macintosh laryngoscope with or without a 3D-printed ergonomic support grip. Primary outcomes were intubation time and overall success rate. Secondary outcomes were number of unsuccessful attempts, first-attempt success rate, airway Cormack-Lehane (CL) grade, and difficulty score. In the easy airway scenario, intubation time, and the overall success rate were similar between two group. CL grade and ease-of-use scores were significantly better for those using the ergonomic support grip (P < 0.05). In the difficult airway scenario, intubation time (49.7±37.5 vs. 35.5±29.2, P = 0.013), the first-attempt success rate (67.5% vs. 90%, P = 0.029), number of attempts (1.4±0.6 vs. 1.1±0.4, P = 0.006), CL grade (2 [2, 2] vs. 2 [1, 1], P = 0.012), and ease-of-use scores (3.5 [2, 4] vs. 4 [3, 5], P = 0.008) were significantly better for those using the ergonomic support grip. Linear mixed model analysis showed that the ergonomic support grip had a favorable effect on CL grade (P<0.001), ease-of-use scores (P<0.001), intubation time (P = 0.015), and number of intubation attempts (P = 0.029). Our custom 3D-printed ergonomic laryngoscope support grip improved several indicators related to the successful endotracheal intubation in the easy and difficult scenario simulated on an airway manikin. This grip may be useful for intubation training and practice.

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)

A Manikin Study Comparing McGrath Mac® and Airtraq® with Macintosh Laryngoscope in Tracheal Intubation by Intensive Care Unit Doctors

Objective

To compare the performance of the McGrath Mac® and the Airtraq® with the Macintosh laryngoscope for tracheal intubation.

Design

A manikin study with different simulated difficult airway scenarios.

Methods

Thirty intensive care unit (ICU) doctors (10 specialists and 20 non-specialists) performed intubation by using the 3 airway devices in the manikin with (i) normal airway, (ii) cervical rigidity, and (iii) tongue oedema. The intubation time, success rate, oesophageal intubation and number of episodes of dental injury were measured and compared.

Results

The mean intubation time was significantly less by using the Airtraq® comparing to the McGrath Mac® in the manikin with normal airway (12.77 sec vs. 24.23 sec; p<0.001). Similarly, the mean intubation time was less by using Airtraq® when comparing to the McGrath Mac® in the manikin with cervical rigidity (12.73 sec vs. 17.5 sec; p=0.013). In the scenario of simulated tongue oedema, the mean intubation time of Airtraq® was shorter than Macintosh laryngoscope (24.83 sec vs. 34.20 sec; p=0.011) while there was no difference between Airtraq® and the McGrath Mac®. Less dental injury was noted when using the Airtraq® compared to the Macintosh laryngoscope in simulated cervical rigidity (p=0.005) and tongue oedema (p<0.001). Less dental injury was also noted when using the McGrath Mac® compared to the Macintosh laryngoscope in simulated tongue oedema (p<0.001).

Conclusion

Even with prior limited experience in using the McGrath Mac®, the performance of tracheal intubation by using this new device is comparable with the Airtraq®. The McGrath Mac® can be a good alternative for tracheal intubation in difficult airway situations. (Hong Kong j.emerg.med. 2015;22:337-344)

Evaluation of the McGrath MAC and Macintosh laryngoscope for tracheal intubation in 2000 patients undergoing general anaesthesia: the randomised multicentre EMMA trial study protocol

INTRODUCTION

The direct laryngoscopy technique using a Macintosh blade is the first choice globally for most anaesthetists. In case of an unanticipated difficult airway, the complication rate increases with the number of intubation attempts. Recently, McGrath MAC (McGrath) video laryngoscopy has become a widely accepted method for securing an airway by tracheal intubation because it allows the visualisation of the glottis without a direct line of sight. Several studies and case reports have highlighted the benefit of the video laryngoscope in the visualisation of the glottis and found it to be superior in difficult intubation situations. The aim of this study was to compare the first-pass intubation success rate using the (McGrath) video laryngoscope compared with conventional direct laryngoscopy in surgical patients.

METHODS AND ANALYSIS

The EMMA trial is a multicentre, open-label, patient-blinded, randomised controlled trial. Consecutive patients requiring tracheal intubation are randomly allocated to either the McGrath video laryngoscope or direct laryngoscopy using the Macintosh laryngoscope. The expected rate of successful first-pass intubation is 95% in the McGrath group and 90% in the Macintosh group. Each group must include a total of 1000 patients to achieve 96% power for detecting a difference at the 5% significance level. Successful intubation with the first attempt is the primary endpoint. The secondary endpoints are the time to intubation, attempts for successful intubation, the necessity of alternatives, visualisation of the glottis using the Cormack & Lehane score and percentage of glottic opening score and definite complications.

ETHICS AND DISSEMINATION

The project was approved by the local ethics committee of the Medical Association of the Rhineland Palatine state and Westphalia-Lippe. The results of this study will be made available in the form of manuscripts for publication and presentations at national and international meetings.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT 02611986; pre-results.

A comparison of the Airtraq®, McGrath®, and Macintosh laryngoscopes for difficult paediatric intubation: A manikin study

BACKGROUND

The efficacy of devices for difficult intubation in paediatric patients, especially with a Cormack-Lehane grade 4 view, has yet to be established. We compared intubating parameters among three devices (the Airtraq®, McGrath®, and Macintosh laryngoscopes).

METHODS

This study is a randomised cross-over trial. Participants were 20 anaesthetists. Each device was tested three times using a paediatric manikin with a Cormack-Lehane grade 4 view. The order to use each device was randomised by a computer-generated random sequence. The primary endpoint was the rate of successful intubation. Secondary endpoints included the time taken to intubate, percentage of glottic opening score, and severity of potential dental trauma.

RESULTS

The successful intubation rates of the Airtraq®, McGrath®, and Macintosh laryngoscopes were 100%, 72%, and 45%, respectively. The risk ratio of the success rates of Airtraq® compared with McGrath® and Macintosh laryngoscopes were 1.40 (95% CI; 1.19-1.64, P < 0.001) and 2.22 (95% CI; 1.68-2.94, P < 0.001), respectively. The modified Cormack-Lehane grade and percentage of the glottic opening score were better for the Airtraq® than for the other devices. The dental trauma score was lower for the Airtraq® than for the other devices. There were no significant differences in the intubation time among the groups.

CONCLUSIONS

The Airtraq® had higher success rate, had better visibility, and was associated with less dental trauma than the other devices in a difficult paediatric intubation model with a Cormack-Lehane grade 4 view.

Video Laryngoscopy Improves Odds of First-Attempt Success at Intubation in the Intensive Care Unit. A Propensity-matched Analysis

RATIONALE

Urgent tracheal intubation is performed frequently in intensive care units and incurs higher risk than when intubation is performed under more controlled circumstances. Video laryngoscopy may improve the chances of successful tracheal intubation on the first attempt; however, existing comparative data on outcomes are limited.

OBJECTIVES

To compare first-attempt success and complication rates during intubation when using video laryngoscopy compared with traditional direct laryngoscopy in a tertiary academic medical intensive care unit.

METHODS

We prospectively collected and analyzed data from a continuous quality improvement database of all intubations in one medical intensive care unit between January 1, 2012, and December 31, 2014. Propensity matching and multivariable logistic regression were used to reduce the risk of bias and control for confounding.

MEASUREMENTS AND MAIN RESULTS

A total of 809 intubations took place over the study period. Of these, 673 (83.2%) were performed using video laryngoscopy and 136 (16.8%) using direct laryngoscopy. First-attempt success with video laryngoscopy was 80.4% (95% confidence interval [CI], 77.2-83.3%) compared with 65.4% (95% CI, 56.8-73.4%) for intubations performed with direct laryngoscopy (P < 0.001). In a propensity-matched analysis, the odds ratio for first-attempt success with video laryngoscopy versus direct laryngoscopy was 2.81 (95% CI, 2.27-3.59). The rate of arterial oxygen desaturation events during the first intubation attempt was significantly lower for video laryngoscopy than for direct laryngoscopy (18.3% vs. 25.9%; P = 0.04). The rate of esophageal intubation during any attempt was also significantly lower for video laryngoscopy (2.1% vs. 6.6%; P = 0.008).

CONCLUSIONS

Video laryngoscopy was associated with significantly improved odds of first-attempt success at tracheal intubation by nonanesthesiologists in a medical intensive care unit. Esophageal intubation and oxygen desaturation occurred less frequently with the use of video laryngoscopy. Randomized clinical trials are needed to confirm these findings.

McGRATH MAC video laryngoscope for insertion of a transoesophageal echocardiography probe: A randomised controlled trial

BACKGROUND

Transoesophageal echocardiography (TOE) probe insertion in anaesthetised patients can cause pharyngeal and oesophageal injuries. Kim et al. have shown that insertion assisted by a Macintosh laryngoscope can reduce such complications but it may sometimes be difficult to observe the passage of a TOE probe. The McGRATH MAC (McGRATH) has been shown to provide a better view of the glottis, piriform fossa and oesophageal inlet during tracheal intubation than the Macintosh.

OBJECTIVE

We hypothesised that the McGRATH provided better visualisation of the oesophageal inlet and was useful as an aid to TOE probe placement, possibly reducing the incidence of pharyngeal injury related to insertion, compared with the Macintosh.

DESIGN

A randomised controlled trial.

SETTING

The study was conducted in a university hospital from February to December 2014.

PATIENTS

One hundred patients undergoing elective surgery under intraoperative TOE monitoring were randomised to either a Macintosh group or a McGRATH group.

INTERVENTIONS

Macintosh and McGRATH were used to visualise the passage of the TOE probe and guide its insertion.

MAIN OUTCOME MEASURES

Visibility of the oesophageal inlet, the number of TOE insertion attempts and incidence of pharyngeal mucosal injury after the TOE probe had been removed were assessed.

RESULTS

The percentage of patients in whom the oesophageal inlet was visible was higher in the McGRATH group (88%) than in the Macintosh group (41%) (P < 0.01). The number of TOE probe insertion attempts was significantly smaller in the McGRATH group than in the Macintosh group (P = 0.039). The incidence of pharyngeal mucosal injury was significantly smaller in the McGRATH group (4%) than in the Macintosh group (16%; P = 0.042).

CONCLUSION

The McGRATH provided a better view of the oesophageal inlet and was useful as an aid to TOE probe placement, possibly reducing the incidence of pharyngeal injury related to its insertion.

TRIAL REGISTRATION

University Hospital Medical Information Network in Japan (UMIN) 000012970.

McGrath Series 5 videolaryngoscope vs Airtraq DL videolaryngoscope for double-lumen tube intubation: A randomized trial

BACKGROUND

Many studies have shown Airtraq videolaryngoscope provided faster tracheal intubation and a higher success rate than other videolaryngoscopes. Recently, different types of videolaryngoscopes have been reported for use in double-lumen tube (DLT) intubation. However, the advantages and disadvantages between them remain undetermined for DLT intubation. In this study, we compared the Airtraq DL videolaryngoscope with the McGrath Series 5 videolaryngoscope for DLT intubation by experienced anesthesiologists.

METHODS

Ninety patients with expected normal airways were randomly allocated to either the Airtraq or McGrath group. The primary outcome was DLT intubation time. The secondary outcomes were glottic view, success rate, subjective ease of intubation (100-mm visual analog scale, 0 = easy; 100 = difficult), incidence of DLT malposition, and postoperative intubation-related complication.

RESULTS

The airway characteristics were comparable between the 2 groups. Cormack and Lehane grades significantly improved with the use of the McGrath and Airtraq videolaryngoscopes, compared with the Macintosh laryngoscope. The intubation success rate on the first attempt was 93% in the Airtraq group and 95% in the McGrath group (P > 0.05). The intubation time in the McGrath group is longer than that in the Airtraq group (39.9 [9.1]s vs 28.6 [13.6]s, P < 0.05). But intubation difficulty score, the incidence of DLT malposition and intubation-related complication were comparable between groups (P > 0.05).

CONCLUSIONS

When using videolaryngoscopes for DLT intubation, the Airtraq DL is superior to the McGrath Series 5 in intubation time, but it does not decrease intubation difficulty.

Comparing McGRATH® MAC, C-MAC®, and Macintosh Laryngoscopes Operated by Medical Students: A Randomized, Crossover, Manikin Study

We hypothesized that the McGRATH MAC would decrease the time of intubation compared to C-MAC for novices. Thirty-nine medical students who had used the Macintosh blade to intubate a manikin fewer than 3 times were recruited. The participants performed sequential intubations on the manikin in two simulated settings that included a normal airway and a difficult airway (tongue edema). The intubation time, success rate of intubation, Cormack-Lehane grade at laryngoscopy, and difficulty using the device were recorded. Each participant was asked to identify the device that was most useful. The intubation time decreased significantly and by a similar amount to the McGRATH MAC and C-MAC compared to the Macintosh blade (P < 0.001 and P = 0.017, resp.). In the difficult airway, the intubation times were similar among the three devices. The McGRATH MAC and C-MAC significantly increased the success rate of intubation, improved the Cormack-Lehane grade, and decreased the difficulty score compared to the Macintosh blade in both airway settings. The majority of participants selected the McGRATH MAC as the most useful device. The McGRATH MAC and C-MAC may offer similar benefits for intubation compared to the Macintosh blade in normal and difficult airway situations.

Retention of laryngoscopy skills in medical students: a randomised, cross-over study of the Macintosh, A.P. Advance(™) , C-MAC(®) and Airtraq(®) laryngoscopes

In addition to being effective and easy to learn how to use, the ideal laryngoscope should be associated with minimal reduction in skill performance during gaps in practice over time. We compared the time taken to intubate the trachea of a manikin by novice medical students immediately after training, and then after 1 month, with no intervening practice. We designed a two-period, four-group, randomised, cross-over trial to compare the Macintosh, Venner(™) A.P. Advance(™) with difficult airway blade, C-MAC(®) with D-Blade and Airtraq(®) with wireless video-viewer. A bougie was used to aid intubation with the Macintosh and the C-MAC. After training, there was no significant difference in median (IQR [range]) intubation time using the videolaryngoscopes compared with the Macintosh, which took 30 (26.5-35 [12-118])s. One month later, the intubation time was longer using the C-MAC (41 (29.5-52 [20-119])s; p = 0.002) and A.P. Advance (40 (28.5-57.5 [21-107])s; p = 0.0003)m compared with the Macintosh (27 (21-29 [16-90])s); there was no difference using the Airtraq (27 (20.5-32.5 [15-94])s; p = 0.258) compared with the Macintosh. While skill acquisition after a brief period of learning and practice was equal for each laryngoscope, performance levels differed after 1 month without practice. In particular, the consistency of performance using the C-MAC and A.P. Advance was worse compared with the Macintosh and the Airtraq. While the clinical significance of this is doubtful, we believe that reliable and consistent performance at laryngoscopy is desirable; for the devices that we tested, this requires regular practice.

Intubation Performance of Advanced Airway Devices in a Helicopter Emergency Medical Service Setting

OBJECTIVE

This study attempts to determine if newer indirect laryngoscopes or intubating devices are superior to a standard laryngoscope for intubation success among helicopter emergency medical service (HEMS) personnel.

METHODS

Flight nurses and paramedics intubated standardized mannequins with a normal airway, a trauma airway, and a difficult airway using a standard laryngoscope, a gum elastic bougie, the Airtraq laryngoscope (King System Corp, Noblesville, IN), the Glidescope Ranger laryngoscope (Verathon Inc, Bothell, WA), and the S.A.L.T. device (Microtek Medical, Inc, Lehmberg, IN) in grounded helicopters wearing helmets and flight gear. Participant demographics, time to glottic view, the modified Cormack-Lehane score, total intubation time, number of attempts, and overall successful intubation were recorded for each type of airway.

RESULTS

Two-hundred thirty-six subjects were initially enrolled across 107 bases in 15 states, and 177 completed the study. First-attempt success rates did not vary by device for the normal airway (P = .203), but the Airtraq laryngoscope and the S.A.L.T. device were highest in the difficult airway (82.0% and 85.0%, respectively; P < .0001). The time to first-attempt success in the difficult airway was lowest for the S.A.L.T. device and the Airtraq laryngoscope (mean = 9.72 seconds and 19.70 seconds, respectively; P < .0001).

CONCLUSION

Using HEMS providers, the Airtraq laryngoscope and the S.A.L.T. device showed the fastest and highest intubation success on the first attempt in difficult simulated HEMS airway scenarios.

Intubation of a Paediatric Manikin in Tongue Oedema and Face-to-Face Simulations by Novice Personnel: a Comparison of Glidescope, Airtraq and Direct Laryngoscopy

OBJECTIVE

Glidescope and Airtraq were designed for facilitating intubation and for teaching regarding the airway anatomy. We aimed to evaluate their efficacy in normal airway, tongue oedema and face-to-face orotracheal intubation models when used by novice personnel.

METHODS

After the local human research ethics committee approval, 36 medical students who were in the beginning of their third year were enrolled in this study. After watching a video regarding intubation using one of these devices, the students intubated a paediatric manikin with a Glidescope or Airtraq via the normal airway, tongue oedema and face-to-face approach.

RESULTS

Although the insertion and intubation times were similar among the groups, the intubation success rate of the Glidescope was higher in the normal airway (100% vs 67%) and tongue oedema (89% vs. 50%) compared with the Airtraq (p=0.008 and p=0.009). The success rates with the paediatric manikin by the face-to-face approach were similar among the groups (50%) (p=0.7). The need for manoeuvres in the Glidescope was lower in the normal and tongue oedema models (p=0.02 and p=0.002). In addition, oesophageal intubation was low in the control and tongue oedema models with the Glidescope (p=0.03 and p<0.001).

CONCLUSION

Novice personnel could more easily intubate the trachea with the Glidescope than with the Airtraq. Intubation with the Glidescope was superior to that with the Airtraq in the normal and tongue oedema models. The face-to-face intubation success rates were both low with both the Glidescope and Airtraq groups.

Comparison of the GlideScope and the McGrath method using vascular forceps and a tube exchanger in cases of simulated difficult airway intubation

Background

A "difficult airway" can be simulated with an extrication collar, which restricts cervical motion and mouth opening. The purpose of this study is to compare the efficacy of the GlideScope and the McGrath in difficult airway simulation.

Methods

Patients were randomized using computer-generated numbers and were placed into the GlideScope group or the McGrath group. The total intubation time was defined as the time measured from when the anesthesiologist picks up the device to the time at which three successive end-tidal CO₂ values are acquired after intubation.

Results

There was no significant difference in total intubation time between the two groups (73.0 ± 25.3 sec vs. 72.3 ± 20.9 sec, P = 0.92). The success rates of the first intubation attempt did not differ between the two groups (82.8% vs. 83.3%, P = 0.95).

Conclusions

Our results suggest that there are no significant differences in the intubations with GlideScope and McGrath using vascular forceps and tube exchangers in difficult intubation scenarios.

[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 of hemodynamic responses to laryngoscopy and intubation with Truview PCD™, McGrath® and Macintosh laryngoscope in patients undergoing coronary artery bypass grafting: A randomized prospective study

CONTEXT

We hypothesized that reduced oropharyngolaryngeal stimulation with video laryngoscopes would attenuate hemodynamic response to laryngoscopy and intubation.

AIM

Comparison of hemodynamic response to laryngoscopy and intubation with video laryngoscopes and Macintosh (MC) laryngoscope.

SETTING AND DESIGN

Superspecialty tertiary care public hospital; prospective, randomized control study.

METHODS

Sixty adult patients undergoing elective coronary artery bypass grafting (CABG) were randomly allocated to three groups of 20 each: MC, McGrath (MG), and Truview™. Hemodynamic parameters were serially recorded before and after intubation. Laryngoscopic grade, laryngoscopy, and tracheal intubation time, ST segment changes, and intra-/post-operative complications were also recorded and compared between groups.

STATISTICAL ANALYSIS

SPSS version 17 was used, and appropriate tests applied. P < 0.05 was considered significant.

RESULTS

Heart rate and diastolic arterial pressure increased at 0 and 1 min of intubation in all the three groups (P < 0.05) while mean arterial pressure increased at 0 min in the MG and TV groups and at 1 min in all three groups (P < 0.05). A significant increase in systolic arterial pressure was only observed in TV group at 1 min (P < 0.05). These hemodynamic parameters returned to baseline by 3 min of intubation in all the groups. The intergroup comparisons of all hemodynamic parameters were not significant at any time of observation. Highest intubation difficulty score was observed with MC (2.16 ± 1.86) as compared with MG (0.55 ± 0.88) and TV (0.42 ± 0.83) groups (P = 0.003 and P = 0.001, respectively). However, duration of laryngoscopy and intubation was significantly less in MC (36.68 ± 16.15 s) as compared with MG (75.25 ± 30.94 s) and TV (60.47 ± 27.45 s) groups (P = 0.000 and 0.003, respectively).

CONCLUSIONS

Video laryngoscopes did not demonstrate any advantage in terms of hemodynamic response in patients with normal airway undergoing CABG.

Tracheal intubation in patients with anticipated difficult airway using Boedeker intubation forceps and McGrath videolaryngoscope

BACKGROUND

Videolaryngoscopes with sharp angulated blades improve the view of the vocal cords but this does not necessarily result in higher success rates of intubation The aim of this study was to evaluate the efficacy of using Boedeker intubation forceps in conjunction with McGrath Series 5 Videolaryngoscope (MVL) in patients with predictors for difficult intubation.

METHODS

The study was conducted at the Department of Anaesthesia, Copenhagen University Hospital from September to December 2013. Patients with one or more predictors of difficult intubation scheduled for general anaesthesia were assessed for eligibility. Patients were intubated using Boedeker intubation forceps and MVL. The primary endpoint was time to intubation. The secondary endpoints were intubation success rate, number of intubation attempts, intubation conditions and post-operative hoarseness.

RESULTS

Thirty-three patients were assessed for eligibility, and 25 patients were included in the study with a median SARI score of 3 (IQR 3-4). Twenty-two (88%, 95% confidence interval [74-100%]) of the patients were successfully intubated by the method with a median time to intubation of 115 s (IQR 78-247). Steering and advancement of the tube were reported as acceptable in 21 (84%) and 22 cases (88%), respectively, and excellent in 10 cases (45%) for both measures. Ten cases (40%) were intubated on the first attempt. There were three cases (12%) of failed intubation; in these cases, successful intubation was obtained by using a styletted tube.

CONCLUSION(S)

Most patients with anticipated difficult intubation can be successfully intubated with Boedeker intubation forceps and MVL. However, endotracheal tube placement failed in 3/25 patients despite a good laryngeal view.

A prospective, randomised, clinical study to compare the use of McGrath(®), Truview(®) and Macintosh laryngoscopes for endotracheal intubation by novice and experienced Anaesthesiologists

Background and Aims:

Video laryngoscopy has been recommended as an alternative during difficult conventional direct laryngoscopy using the Macintosh blade (MAC). However, successful visualisation of the larynx and tracheal intubation using some of the indirect laryngoscopes or video laryngoscopes (VL) requires hand-eye coordination. We conducted this study to determine whether non-channel VLs are easy to use for novices and whether there is any association between expertise with MAC and ease of tracheal intubation with VLs.

Methods:

Anaesthesiologists participating in the study were divided into three groups: Group novice to intubation (NTI), Group novice to videoscope (NVL)- experienced with MAC, novice to VLs and Group expert (EXP) experienced in all. Group NTI, NVL received prior mannequin training. VLs- Truview^® and McGrath series 5 (MGR) were compared with MAC. One hundred and twenty six adult patients with normal airway were randomised to both, the intubating anaesthesiologist and laryngoscope. The time taken to intubate (TTI) and participants’ rating of the ease of use was recorded on a scale of 1–10 (10-most difficult).

Results:

In Group NTI, there was no difference in mean TTI with the three scopes (P = 0.938). In Group NVL, TTI was longer with the VLs than MAC (P < 0.001). In Group EXP, TTI with VL took 20 s more (P < 0.001). There was significant difference in participants’ rating of ease of use of laryngoscope in Group NVL (P = 0.001) but not in the NTI (P = 0.205), EXP (P = 0.529) groups. A high failure was seen with MGR in Group NTI and NVL.

Conclusion:

In Group NTI, TTI and the ease of use were similar for all scopes. Expertise with standard direct laryngoscopy does not translate to expertise with VLs. Separate training and experience with VLs is required.

The AirView Study: Comparison of Intubation Conditions and Ease between the Airtraq-AirView and the King Vision

We conducted a study assessing the quality and speed of intubation between the Airtraq with its new iPhone AirView app and the King Vision in a manikin. The primary endpoint was reduction of time needed for intubation. Secondary endpoints included times necessary for intubation. 30 anaesthetists randomly performed 3 intubations with each device on a difficult airway manikin. Participants had a professional experience of 12 years: 60.0% possessed the Airtraq in their hospital, 46.7% the King Vision, and 20.0% both. Median time difference [IQR] to identify glottis (1.1 [-1.3; 3.9] P = 0.019), for tube insertion (2.1 [-2.6; 9.4] P = 0.002) and lung ventilation (2.8 [-2.4; 11.5] P = 0.001), was shorter with the Airtraq-AirView. Median time for glottis visualization was significantly shorter with the Airtraq-AirView (5.3 [4.0; 8.4] versus 6.4 [4.6; 9.1]). Cormack Lehane before intubation was better with the King Vision (P = 0.03); no difference was noted during intubation, for subjective device insertion or quality of epiglottis visualisation. Assessment of tracheal tube insertion was better with the Airtraq-AirView. The Airtraq-AirView allows faster identification of the landmarks and intubation in a difficult airway manikin, while clinical relevance remains to be studied. Anaesthetists assessed the intubation better with the Airtraq-AirView.

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 of the Airtraq laryngoscope and the GlideScope for double-lumen tube intubation in patients with predicted normal airways: a prospective randomized trial

BACKGROUND

The Airtraq laryngoscope and the GlideScope are commonly used in many airway scenarios. However, their features have not been fully described for double-lumen tube intubation. A prospective randomized study was designed to compare their intubation performances in thoracic surgery patients.

METHODS

Seventy ASA physical status I and II patients with predicted normal airway were scheduled for thoracic surgeries with double-lumen tube intubation. They were randomly assigned to one of two groups and intubated with either the Airtraq laryngoscope (group A, n = 35) or the GlideScope (group G, n = 35). Airway assessments were performed prior to anesthesia, and all patients were induced with a standard anesthetic regimen. The Cormack-Lehane grades were initially evaluated with a Macintosh laryngoscope and subsequently with the group-specific laryngoscope before intubation. Intubation time was recorded as the primary outcome. The Cormack-Lehane grade, the success of the first intubation attempt, the intubation difficulty scales and ease of tube advancement were noted. Hemodynamic variables during intubation and incidence of post-operative sore throat were documented as well.

RESULTS

The intubation time of group A was shorter than that of group G (36.6 ± 20.2 s vs. 54.6 ± 25.7 s, p = 0.002). The Cormack-Lehane grade (I/II/III/IV) was significantly better in group A (33/2/0/0 vs. 28/7/0/0, p = 0.042). The mean arterial pressure and heart rate rose to higher levels during intubation with the GlideScope than with the Airtraq laryngoscope. The success of the first intubation attempt and the intubation difficulty scales were comparable between the two groups. The numbers of patients who experienced postoperative sore throat were similar (6 vs. 8) in the two groups.

CONCLUSIONS

Compared with the GlideScope, the specially designed Airtraq laryngoscope might be more suitable for double-lumen tube intubations in patients with predicted normal airway.

TRIAL REGISTRATION

www.chictr.org Identifier: ChiCTR-TRC-11001628.

[Comparison of GlideScope® Cobalt and McGrath® Series 5 video laryngoscopes with direct laryngoscopy in a simulated regurgitation/aspiration scenario]

BACKGROUND

Video laryngoscopy has become increasingly important in airway management in the pre- and intrahospital settings. However, using video laryngoscopes in the presence of body fluids can make visualization of the airway difficult. A simulated regurgitation model was used to compare two video laryngoscopes (VL) with direct laryngoscopy.

MATERIALS AND METHODS

A total of 72 physicians participated in this randomized trial. The hypopharynx from an Airway Management Trainer was filled with artificially warmed turbid liquid. In addition, the cervical spine of the manikin was immobilized. The VL GlideScope® (GS) and McGrath® Series 5 (McG) were examined with the laryngoscope with Macintoshspatel (DL). Fogging of the camera optics in percent (0 %= clear view, 100 %= no view), the visibility of the glottis by Cormack and Lehane classification (C&L), and the POGO Score (percentage of glottic opening), the time until the endotracheal tube placement, and the success rate were evaluated.

RESULTS

No fogging (median 0 %) was present using the GS (interquartile range [IQR]: 0-4), in contrast 45 % fogging was found in the McG group (IQR: 30-60; p < 0.001). Glottic visualization using C&L was better using VL (p < 0.001). A similar result was observed using the POGO Scale: GS 90 % (IQR: 76-100), McG 80 % (IQR: 70-90), and DL 20 % (IQR: 0-50). The time for correct placement was in the DL with 27.6 s (IQR: 22.5-35) faster (p < 0.001), with the GS 48.5 s (IQR: 34.3-65.1) and the McG 66.3 s (IQR: 45.4-90). Successful placement was possible with GS in all cases (72/72), with DL in 71/72 cases, and with the McG in 70/72 cases.

CONCLUSION

Using a video laryngsocope with an "anti-fogging" system improved visualization in a simulated aspiration model. In this scenario, VL showed no advantage to direct laryngoscopy in terms of success rate and speed of intubation.

[Effectiveness of the GlideScope video laryngoscope in a case of unexpected difficult airway due to lingual tonsil hypertrophy]

Lingual tonsil hypertrophy can cause varying degrees of airway obstruction and is considered a risk factor for difficult mask ventilation and tracheal intubation. We report a case of unexpected difficult airway in a patient with unknown lingual tonsil hypertrophy that was solved with the use of the GlideScope video laryngoscope.

Comparison of the Macintosh, McCoy, Airtraq laryngoscopes and the intubating laryngeal mask airway in a difficult airway with manual in-line stabilisation: a cross-over simulation-based study

CONTEXT

Patients with multisystem trauma undergoing intubation with manual in-line stabilisation (MILS) have a higher incidence of difficult or failed intubations.

OBJECTIVE

To compare the effectiveness of the Macintosh laryngoscope with three other intubating devices in a high fidelity simulation model.

DESIGN

Cross-over, simulation-based study.

SETTING

Tertiary referral and level 1 trauma centre between June and November 2011.

PARTICIPANTS

Thirty-five experienced airway physicians.

INTERVENTION

Each participant performed tracheal intubations on a Laerdal SimMan manikin in both a normal airway and a difficult airway scenario with MILS. The devices utilised in a randomised order were the Macintosh, McCoy, Airtraq laryngoscopes and the intubating laryngeal mask airway (iLMA).

MAIN OUTCOME MEASURES

The primary outcome was time to intubation. Success rates, grade of laryngoscopy and force of intubation were also measured.

RESULTS

One hundred and forty intubations were attempted by 35 participants in both the normal and MILS scenarios. In the normal airway, there was no difference in success rates and time to intubation. In the difficult airway with MILS, there was no difference in success rates. However, the Airtraq was associated with a longer time to intubation than the Macintosh, McCoy and iLMA, 39.3, 26.7, 23.3, 39.3, 22.8 s, respectively (P < 0.0001). The Airtraq delivered the best glottic view and lowest force of intubation in both scenarios (P < 0.0001), but was associated with the only failed intubation in the study. The McCoy was associated with a significant improvement in the glottic visualisation (P < 0.05) and reduction in the force of intubation (P <0.0001) compared with the Macintosh.

CONCLUSION

In this manikin study, the McCoy demonstrated multiple advantages over the Macintosh. The iLMA was associated with the fastest time to intubation and minimum force of insertion.

Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios: a randomised controlled manikin study

BACKGROUND

Flexible fibreoptic endoscopic (FFE) intubation is considered the 'gold-standard' when difficult airway management is anticipated. Several videolaryngoscopes have been developed to facilitate intubation by laryngoscopy.

OBJECTIVE

The aim of the study was to compare the performance of the McGrath series 5 videolaryngoscope (McGrath videolaryngoscope) and the FFE for tracheal intubation in manikins with a simulated difficult airway, hypothesizing that the McGrath videolaryngoscope intubation would prove faster than FFE intubation.

DESIGN

A randomised controlled study.

SETTING

The Danish Institute for medical simulation between December 2009 and June 2010.

PARTICIPANTS

Twenty-eight anaesthesia residents participating in the Danish mandatory 3-day airway management course.

INTERVENTIONS

All participants received instructions and training in the use of the McGrath videolaryngoscope and FFE. The participants then performed tracheal intubation on a SimMan manikin once with the McGrath videolaryngoscope and once with the FFE in three difficult airway scenarios: (1) pharyngeal obstruction; (2) pharyngeal obstruction and cervical rigidity; (3) tongue oedema.

MAIN OUTCOME MEASURES

We measured successful intubations, defined as intubation within 120  s, and time to tracheal intubation.

RESULTS

The trachea was intubated within 120  s with the McGrath videolaryngoscope in 25 out of 27 (93%), 25 out of 28 (89%) and 18 out of 28 (64%) occasions compared with 11 out of 28 (40%), 11 out of 28 (40%) and 16 out of 28 (57%) with the FFE in scenarios (1), (2) and (3), respectively. Time to tracheal intubation was shorter with the McGrath videolaryngoscope in scenarios (1) and (2) than with the FFE (Wilcoxon signed rank sum test, P < 0.0001).

CONCLUSION

The McGrath videolaryngoscope is a valuable device with higher success rate and a quicker performance in simulated difficult airways. In patients, videolaryngoscopy may have a role in difficult airway algorithms, but the optimal device has yet to be found.

Comparison of Airtraq optical laryngoscope and Storz video laryngoscope in a cadaver model

BACKGROUND

Airway management in the emergency department is a critical intervention that requires both standard techniques and rescue techniques to ensure a high rate of success. Recently, video laryngoscope (VL) systems have become increasingly common in many large urban EDs, but these systems may exceed the budgets of smaller rural EDs and EMS services and the Airtraq optical laryngoscope (OL) may provide an effective, low-cost alternative. We hypothesized that laryngeal view and time to endothracheal tube placement for OL and VL intubations would not be significantly different.

METHODS

This was a prospective, crossover trial.

SETTING

University-based emergency medicine residency program procedure laboratory utilizing lightly embalmed cadavers.

SUBJECTS

PGY1-3 emergency medicine residents. The study subjects performed timed endotracheal intubations alternately using the OL and VL. The subjects then rated the Cormack-Lehane laryngeal view for each device.

STATISTICAL ANALYSIS

Mean time to intubation and the mean laryngeal view score were calculated with 95% confidence intervals and statistical significance was determined by Student's t test.

RESULTS

Fourteen subjects completed the study. The average laryngeal view achieved with the OL vs. the VL was not significantly different, with Cormack-Lehane grade of 1.14 vs. 1.07, respectively. Time to endotracheal intubation, however, was significantly different (P<0.001) with the average time to intubation for the OL 25.49 seconds (95% CI: 17.95-33.03) and the VL 13.41 seconds (10.27-16.55).

CONCLUSION

The Airtraq OL and the Storz VL yielded similar laryngeal views in the lightly embalmed cadaver model. Time to endotracheal tube placement, however, was less for the VL.

Effect of rigid cervical collar on tracheal intubation using Airtraq(®)

Background and Aims:

Cervical spine immobilisation with rigid cervical collar imposes difficulty in intubation. Removal of the anterior part of the collar may jeopardize the safety of the cervical spine. The effect of restricted mouth opening and cervical spine immobilisation that result from the application of rigid cervical collar on intubation using Airtraq^® was evaluated.

Methods:

Seventy healthy adults with normal airways included in the study were intubated Using Airtraq® with (group C) and without rigid cervical collar (group NC). The ease of insertion of Airtraq^® into the oral cavity, intubation time, intubation difficulty score (IDS) were compared using Wilcoxon sign ranked test and McNemar test, using SPSS version 13.

Results:

Intubation using Airtraq^® was successful in the presence of the cervical collar in 96% which was comparable to group without collar (P = 0.24). The restriction of mouth opening resulted in mild difficulty in insertion of Airtraq^®. The median Likert scale for insertion was - 1 in the group C and + 1 in group NC (P < 0.001). The intubation time was longer in group C (30 ± 14.3 s vs. 26.9 ± 14.8 s) compared to group NC. The need for adjusting manoeuvres was 18.5% in group C versus 6.2% in group NC (P = 0.003) and bougie was required in 12 (18.5%) and 4 (6.2%) patients in group C and NC, respectively, to facilitate intubation (P = 0.02). The modified IDS score was higher in group C but there was no difference in the number of patients with IDS < 2.

Conclusion:

Tracheal intubation using Airtraq^® in the presence of rigid cervical collar has equivalent success rate, acceptable difficulty in insertion and mild increase in IDS.

Can the new McGrath laryngoscope rival the GlideScope Ranger portable video laryngoscope? A randomized manikin study

PURPOSE

We hypothesized that novices would be able to use the McGrath MAC (Aircraft Medical Ltd, Edinburgh, UK) equally as well as the GlideScope Ranger (Verathon, Inc, Bothell, WA) for intubation in regular simulated airways.

METHODS

We performed a prospective, randomized crossover study of 39 medical students using the McGrath MAC, GlideScope Ranger, and Macintosh in a manikin with 2 normal airways. The primary outcome was the intubation time. Secondary outcomes included the success rates and the overall glottic view of the 3 laryngoscopes.

RESULTS

The mean intubation times for each attempt with the McGrath MAC were 30.8 ± 16.9 seconds or less and did not differ significantly from those obtained with the GlideScope Ranger or the Macintosh in both airway scenarios (P = .18; P = .49). The mean success rates at each attempt with the McGrath MAC were 82.0% ± 38.8% or more, equal to the Macintosh and the GlideScope Ranger in both scenarios (P = .026; P = .72) except during the first intubation attempt in a normal airway (P = .008). The median grades of the glottic view visible at each intubation attempt with the McGrath Mac were Cormack-Lehane grade 1 (scenario 1: interquartile range, 1-1; scenario 2: interquartile range, 1-2), which was significantly better than the Macintosh laryngoscope in both scenarios. However, the McGrath Mac did not produce a better glottic view than the GlideScope Ranger with either scenario.

CONCLUSIONS

The intubation performance of novices using the McGrath MAC was equal to their performance using the GlideScope Ranger in regular simulated airways.

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.

Tracheal intubation in patients with cervical spine immobilization: A comparison of McGrath(®) video laryngoscope and Truview EVO2(®) laryngoscope

BACKGROUND AND AIMS

Literature suggests that glottic view is better when using McGrath(®) Video laryngoscope and Truview(®) in comparison with McIntosh blade. The purpose of this study was to evaluate the effectiveness of McGrath Video laryngoscope in comparison with Truview laryngoscope for tracheal intubation in patients with simulated cervical spine injury using manual in-line stabilisation.

METHODS

This prospective randomised study was undertaken in operation theatre of a tertiary referral centre after approval from the Institutional Review Board. A total of 100 consenting patients presenting for elective surgery requiring tracheal intubation were randomly assigned to undergo intubation using McGrath(®) Video laryngoscope (n = 50) or Truview(®) (n = 50) laryngoscope. In all patients, we applied manual-in-line stabilisation of the cervical spine throughout the airway management. Statistical testing was conducted with the statistical package for the social science system version SPSS 17.0. Demographic data, airway assessment and haemodynamics were compared using the Chi-square test. A P < 0.05 was considered significant.

RESULTS

The time to successful intubation was less with McGrath video laryngoscope when compared to Truview (30.02 s vs. 38.72 s). However, there was no significant difference between laryngoscopic views obtained in both groups. The number of second intubation attempts required and incidence of complications were negligible with both devices. Success rate of intubation with both devices was 100%. Intubation with McGrath Video laryngoscope caused lesser alterations in haemodynamics.

CONCLUSIONS

Both laryngoscopes are reliable in case of simulated cervical spine injury using manual-in-line stabilisation with 100% success rate and good glottic view.

Cardiac arrest is a predictor of difficult tracheal intubation independent of operator experience in hospitalized patients

Background

Placement of advanced airways has been associated with worsened neurologic outcome in survivors of out-of-hospital cardiac arrest. These findings have been attributed to factors such as inexperienced operators, prolonged intubation times and other airway related complications. As an initial step to examine outcomes of advanced airway placement during in-hospital cardiac arrest (IHCA), where immediate assistance and experienced operators are continuously available, we examined whether cardiopulmonary resuscitation efforts affect intubation difficulty. Additionally, we examined whether or not the use of videolaryngoscopy increases the odds of first attempt intubation success compared with traditional direct laryngoscopy.

Methods

The study setting is a large urban university-affiliated teaching hospital where experienced airway managers are available to perform emergent intubation for any indication in any out-of-the-operating room location 24 hours a day, 7 days-a-week, 365 days-a-year. Intubations occurring in all adults >18 years-of-age who required emergent tracheal intubation outside of the operating room between January 1, 2008 and December 31, 2012 were examined retrospectively. Multivariate logistic regression was used to estimate the odds of difficult intubation during IHCA compared to other emergent non-IHCA indications with adjustment for a priori defined potential confounders (body mass index, operator experience, use of videolaryngoscopy versus direct laryngoscopy, and age).

Results

In adjusted analyses, the odds of difficult intubation were higher when taking place during IHCA (OR=2.63; 95% CI 1.1-6.3, p=0.03) compared to other emergent indications. Use of video versus direct laryngoscopy for initial intubation attempts during IHCA, however, did not improve the odds of success (adjusted OR = 0.71; 95% CI 0.35-1.43, p = 0.33).

Conclusions

Difficult intubation is more likely when intubation takes place during IHCA compared to other emergent indications, even when experienced operators are available. Under these conditions, direct laryngoscopy (versus videolaryngoscopy) remains a reasonable first choice intubation technique.

First comparison of the Venner(TM) A.P. Advance(TM) versus the Macintosh laryngoscope for intubations by non-anaesthetists: a manikin study

OBJECTIVE

The present study aims to study whether using a videolaryngoscope (A.P. Advance™) facilitates or hinders intubation by non-anaesthetists inexperienced in its use.

METHODS

Thirty doctors from Emergency and Intensive Care Medicine backgrounds performed laryngoscopy and tracheal intubation using the Macintosh laryngoscope (MAC), A.P. Advance™ Normal Blade (AP N) and A.P. Advance™ Difficult Airway Blade (AP DAB) in simulated normal and difficult airway manikins. The primary outcomes measured were time to successful tracheal intubation and failure to intubate within 3 min or three attempts. Secondary outcomes were number of intubation attempts, adjuncts used, glottic view and ease of intubation.

RESULTS

There was a higher rate of failed intubation in the simulated difficult airway in participants using the AP N blade than either the MAC or AP DAB (23% vs 3% and 7%, P = 0.031). This was associated with a longer median time to intubate with the AP N and the AP DAB versus MAC (56.6, 50.2 vs 39.9 s, P = 0.007 and P = 0.041). In the normal airway median time to intubate was longest with the AP N (27.8 s), and this was significantly slower than the MAC (18.1 s, P = 0.003) and the AP DAB (17.3 s, P < 0.001). No one failed to intubate the normal manikin.

CONCLUSIONS

The use of the A.P. Advance™ videolaryngoscope should not be considered, without adequate prior training and experience, in the management of a difficult airway. The level of adequate training has yet to be established.

Postoperative sore throat after laryngoscopy with macintosh or glide scope video laryngoscope blade in normal airway patients

Background:

The Glide Scope videolaryngoscope provides a suitable view for intubation, with less force required.

Objectives:

The present study was conducted, to compare postoperative sore throat and hoarseness after laryngoscopy and intubation, by Macintosh blade or Glide Scope video laryngoscope in normal airway patients.

Patients and Methods:

Three hundred patients were randomly allocated into two groups of 150: Macintosh blade laryngoscope or Glide Scope video laryngoscope. The patients were evaluated for 48 hours for sore throat and hoarseness by an interview.

Results:

The incidence and severity of sore throat in the Glide Scope group, at 6, 24 and 48 hours after the operation, were significantly lower than in the Macintosh laryngoscope group. In addition, the incidence of hoarseness in the Glide Scope group, at 6 and 24 hours after the operation, were significantly lower than in the Macintosh laryngoscope group. The incidence and severity of sore throat in men, at 6 and 24 hours after the operation, were significantly lower than in the women.

Conclusions:

The incidence and severity of sore throat and hoarseness after tracheal intubation by Glide Scope were lower than in the Macintosh laryngoscope. The incidence and severity of sore throat were increased by intubation and longer operation times.