Ease of intubation with the GlideScope or Airway Scope by novice operators in simulated easy and difficult airways - 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.

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.

Medical student simulation training in intrauterine contraception insertion and removal: an intervention to improve comfort, skill, and attitudes

Background

Opportunities for medical students to place intrauterine contraception (IUC) in patients are rare. Our objective was to determine whether participation in an IUC insertion and removal simulation exercise would increase medical students’ comfort level with, attitudes towards, and willingness to recommend IUC.

Methods

A prospective cohort study was undertaken in all students completing the obstetrics and gynecology clerkship at a major academic hospital during the 2010–2011 academic year. The exposure consisted of a 45-minute interactive didactic session and a 30-minute, hands-on practicum in IUC placement and removal using medical instruments and realistic pelvic models. Both levonorgestrel and Cu380A IUC devices were utilized. Participants completed a pre- and post-simulation survey instrument, designed to examine students’ IUC-specific knowledge, comfort, and attitudes. Pre- and post-simulation responses were compared by McNemar’s test for paired samples.

Results

Thirty-five paired pre- and post-simulation surveys were analyzed, representing a 78 % response rate. Composite IUC-related knowledge scores increased by a median of 3 out of 10 points after the intervention (p < 0.01). Students were significantly more comfortable counseling patients about IUC as well as inserting IUC after the intervention, compared to before. Seven (20 %) students before, compared to 27 (77 %) after, agreed with the statement, “I feel comfortable placing an IUC in a patient under the supervision of an experienced doctor” (p < 0.01). Students developed significantly more favorable attitudes towards IUC through the intervention. Nineteen (54 %) participants before, compared to 27 (77 %) after, agreed with the statement, “I would recommend an IUC to my family member” (p = 0.02).

Conclusions

A hands-on simulation during the obstetrics and gynecology clerkship increased medical students’ knowledge of and comfort with IUC and resulted in more favorable attitudes toward the method. Intrauterine contraception simulation in medical curricula may help expand utilization of this effective contraceptive method.

A review of video laryngoscopes relevant to the intensive care unit

The incidence of difficult direct intubation in the intensive care unit (ICU) is estimated to be as high as 20%. Recent advances in video-technology have led to the development of video laryngoscopes as new intubation devices to assist in difficult airway management. Clinical studies indicate superiority of video laryngoscopes relative to conventional direct laryngoscopy in selected patients. They are therefore an important addition to the armamentarium of any clinician performing endotracheal intubation. We present a practical review of commonly available video laryngoscopes with respect to design, clinical efficacy, and safety aspects relevant to their use in the ICU.

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.

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.

Difficult Airway Management for Novice Physicians

Objectives

To detect a difference in (1) intubation success and (2) successful intubation times between novice physicians using a Macintosh-style or video-assisted laryngoscope on a difficult airway manikin.

Study Design

Prospective randomized trial.

Setting

Academic, tertiary medical center.

Methods

Forty first-year residents across a variety of disciplines with fewer than 5 total live intubations were recruited for the study. Testing took place during orientation prior to commencement of clinical duties. The entire group was provided training by faculty otolaryngologists and anesthesiologists using both laryngoscope types on a manikin airway simulator in a standard intubating scenario. Subjects were then randomized into 2 testing groups, using either a Macintosh laryngoscope or video-assisted laryngoscope in a difficult intubation scenario. The difficult airway simulation entailed oral cavity/oropharyngeal obstruction using inflation of the tongue, as well as cervical spine immobilization with a rigid collar preventing extension and elevation of the head and limiting oral cavity opening. Success was defined as a confirmed endotracheal intubation by the testing instructor in 120 seconds or less.

Results

The Macintosh laryngoscope group (n = 19) had an intubation success rate of 47.4% with a mean intubation time of 69.0 seconds (95% confidence interval [CI]: 52.7, 85.2). The video-assisted group (n = 21) demonstrated a significantly higher success rate of 100% ( P < .0001) and a decreased mean intubation time of 23.1 seconds (95% CI: 18.4, 27.8; P < .0001). The mean difference in success rate between groups was 52.6% (95% CI: 30.0%, 75.3%).

Conclusions

Novice physicians with little to no prior intubation experience showed significantly higher intubation success with lower intubation times using a video-assisted laryngoscope in a difficult airway manikin simulator.

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.

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.

Randomized controlled trial comparing the McGrath videolaryngoscope with the C-MAC videolaryngoscope in intubating adult patients with potential difficult airways

BACKGROUND

Difficult and failed intubations, although rarely encountered, are major causes of morbidity and mortality in the current anaesthetic practice. To reduce the incidence of difficult and failed intubations, several devices including the recently developed videolaryngoscopes are available. This randomized controlled study aims to compare the use of the McGrath videolaryngoscope with the C-MAC videolaryngoscope in adult patients with potential difficult airways.

METHODS

A total of 130 patients with the Mallampati grade of ≥3, requiring orotracheal intubation, were randomized to either having intubation with the McGrath videolaryngoscope or the C-MAC videolaryngoscope. The primary outcome was time to intubation. The laryngoscopic view, the number of intubation attempts, the proportion of intubation success, the ease of intubation, the haemodynamic responses to intubation, and the incidence of any complications were also recorded.

RESULTS

Time to successful intubation with the C-MAC videolaryngoscope was shorter when compared with the McGrath videolaryngoscope {50 s [inter-quartile range (IQR) 38-70] vs 67 s (IQR 49-108), P<0.001}, despite the McGrath videolaryngoscope providing significantly more grade 1 laryngoscopic views. The C-MAC videolaryngoscope also resulted in significantly fewer intubation attempts and greater ease of intubation when compared with the McGrath videolaryngoscope. There were no statistically significant differences in the proportion of intubation success, the number of complications, and the changes in haemodynamic responses between the two videolaryngoscopes.

CONCLUSIONS

The C-MAC videolaryngoscope allowed a quicker intubation time, fewer intubation attempts, and greater ease of intubation compared with the McGrath videolaryngoscope when used in patients with the Mallampati grade of ≥3.

A comparison of the C-MAC video laryngoscope to the Macintosh direct laryngoscope for intubation in the emergency department

STUDY OBJECTIVE

We determine the proportion of successful intubations with the C-MAC video laryngoscope (C-MAC) compared with the direct laryngoscope in emergency department (ED) intubations.

METHODS

This was a retrospective analysis of prospectively collected data entered into a continuous quality improvement database during a 28-month period in an academic ED. After each intubation, the operator completed a standardized data form evaluating multiple aspects of the intubation, including patient demographics, indication for intubation, device(s) used, reason for device selection, difficult airway characteristics, number of attempts, and outcome of each attempt. Intubation was considered ultimately successful if the endotracheal tube was correctly inserted into the trachea with the initial device. An attempt was defined as insertion of the device into the mouth regardless of whether there was an attempt to pass the tube. The primary outcome measure was ultimate success. Secondary outcome measures were first-attempt success, Cormack-Lehane view, and esophageal intubation. Multivariate logistic regression analyses, with the inclusion of a propensity score, were performed for the outcome variables ultimate success and first-attempt success.

RESULTS

During the 28-month study period, 750 intubations were performed with either the C-MAC with a size 3 or 4 blade or a direct laryngoscope with a Macintosh size 3 or 4 blade. Of these, 255 were performed with the C-MAC as the initial device and 495 with a Macintosh direct laryngoscope as the initial device. The C-MAC resulted in successful intubation in 248 of 255 cases (97.3%; 95% confidence interval [CI] 94.4% to 98.9%). A direct laryngoscope resulted in successful intubation in 418 of 495 cases (84.4%; 95% CI 81.0% to 87.5%). In the multivariate regression model, with a propensity score included, the C-MAC was positively predictive of ultimate success (odds ratio 12.7; 95% CI 4.1 to 38.8) and first-attempt success (odds ratio 2.2; 95% CI 1.2 to 3.8). When the C-MAC was used as a video laryngoscope, a Cormack-Lehane grade I or II view (video) was obtained in 117 of 125 cases (93.6%; 95% CI 87.8% to 97.2%), whereas when a direct laryngoscope was used, a grade I or II view was obtained in 410 of 495 cases (82.8%; 95% CI 79.2% to 86.1%). The C-MAC was associated with immediately recognized esophageal intubation in 4 of 255 cases (1.6%; 95% CI 0.4% to 4.0%), whereas a direct laryngoscope was associated with immediately recognized esophageal intubation in 24 of 495 cases (4.8%; 95% CI 3.1% to 7.1%).

CONCLUSION

When used for emergency intubations in the ED, the C-MAC was associated with a greater proportion of successful intubations and a greater proportion of Cormack-Lehane grade I or II views compared with a direct laryngoscope.

Simulation and anaesthesia

Training in anaesthesia relies on the duration and quality of clinical experience. It involves exposure to a range of interventions. This works well in routine cases, but when an uncommon and life-threatening event occurs, the anaesthetist needs to carry out multiple tasks simultaneously. Aviation has remarkable similarities with the practice of anaesthesia. Over the years, the aviation industry has used simulation to train and assess individuals very effectively. Anaesthetists face rapidly evolving clinical situations. This needs appropriate decision-making and communication with others in the theatre team. Simulation, using current technology, offers innovative and reproducible training experience. It enables standardised scenario building and reflective learning. Various non-technical aspects of an anaesthetist's day-to-day work could also be addressed to during such training. The technology could be used very effectively for the assessment of competence too. Simulation has been used for technology development and appraisal over the years.

Difficult airway management in the emergency department: GlideScope videolaryngoscopy compared to direct laryngoscopy

BACKGROUND

Videolaryngoscopy has become a popular method of intubation in the Emergency Department (ED), however, little research has compared this technique with direct laryngoscopy (DL).

OBJECTIVE

To compare the success rates of GlideScope (Verathon Inc., Bothell, WA) videolaryngoscopy (GVL) and DL in emergent airways with known difficult airway predictors (DAPs).

METHODS

We evaluated 772 consecutive ED intubations over a 23-month period. After each intubation, the physician completed a data collection form that included: demographics, DAPs, Cormack-Lehane view, optical clarity, lens contamination, and complications. DAPs included: cervical immobility, obesity, small mandible, large tongue, short neck, blood or vomit in the airway, tracheal edema, secretions, and facial or neck trauma. Primary outcome was first-attempt success rates. Multivariate logistic regression was performed to evaluate the odds of failure for DL compared to GVL.

RESULTS

First-attempt success rate with DL was 68%, GVL 78% (Fisher's exact test, p = 0.001). Adjusted odds of success of GVL compared to DL on first attempt equals 2.20 (odds ratio [OR] 2.2, 95% confidence interval [CI] 1.51-3.19). After statistically controlling for DAPs, GVL was more likely to succeed on first attempt than DL (OR 3.07, 95% CI 2.19-4.30). Logistic regression of DAPs showed that the presence of blood, small mandible, obesity, and a large tongue were statistically significant risk factors for decreasing the odds of success with DL and increasing the odds of success of GVL.

CONCLUSION

For difficult airways with the presence of blood or small mandible, or a large tongue or obesity, GVL had a higher success rate at first attempt than DL.

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.

Evaluation of the Pentax-AWS(®) and the Macintosh laryngoscope in difficult intubation: a manikin study

BACKGROUND

The Pentax-AWS (AWS(®)), a new video laryngoscope, has been shown to be useful in cases of difficult intubation. We hypothesized that the AWS(®) would be more useful in the settings of a narrow upper airway than the Macintosh laryngoscope. We compared each device in simulated scenarios of representative difficulty of tracheal intubation using a manikin. The primary endpoint was the rate of successful intubation.

METHODS

With each device, 23 anesthesiologists performed tracheal intubation in a SimMan(®) manikin in the following scenarios: (1) normal airway, (2) tongue edema, (3) cervical spine rigidity, (4) pharyngeal obstruction, (5) jaw trismus, (6) tongue edema with pharyngeal obstruction. The intubation time and success rate were measured. Each participant was asked to rate the difficulty of intubation (1=very easy; 5=very difficult).

RESULTS

In the scenarios of tongue edema and tongue edema with pharyngeal obstruction, the AWS(®) yielded a higher success rate (100% vs. 34.8%; P<0.001, 65.2% vs. 21.7%; P=0.006), a shorter intubation time [14.6 (7.0) vs. 33.4 (13.0) s; P<0.001, 24.5 (12.0) vs. 37.6 (11.9); P=0.047; mean (standard deviation)], and a lower difficulty score [2 (1-4) vs. 5 (1-5); P<0.001, 4 (2-5) vs. 5 (3-5); P<0.001; median (range)], compared with the Macintosh laryngoscope.

CONCLUSION

The AWS(®) has an advantage over the Macintosh laryngoscope in simulated tongue edema and tongue edema with pharyngeal obstruction. Further studies in a clinical setting are necessary to confirm these findings.

Assessment of the storz video Macintosh laryngoscope for use in difficult airways: A human simulator study

OBJECTIVES

Video laryngoscopy has been shown to improve glottic exposure when compared to direct laryngoscopy in operating room studies. However, its utility in the hands of emergency physicians (EPs) remains undefined. A simulated difficult airway was used to determine if intubation by EPs using a video Macintosh system resulted in an improved glottic view, was easier, was faster, or was more successful than conventional direct laryngoscopy.

METHODS

Emergency medicine (EM) residents and attending physicians at two academic institutions performed endotracheal intubation in one normal and two identical difficult airway scenarios. With the difficult scenarios, the participants used video laryngoscopy during the second case. Intubations were performed on a medium-fidelity human simulator. The difficult scenario was created by limiting cervical spine mobility and inducing trismus. The primary outcome was the proportion of direct versus video intubations with a grade I or II Cormack-Lehane glottic view. Ease of intubation (self-reported via 10-cm visual analog scale [VAS]), time to intubation, and success rate were also recorded. Descriptive statistics as well as medians with interquartile ranges (IQRs) are reported where appropriate. The Wilcoxon matched pairs signed-rank test was used for comparison testing of nonparametric data.

RESULTS

Participants (n = 39) were residents (59%) and faculty. All had human intubation experience; 51% reported more than 100 prior intubations. On difficult laryngoscopy, a Cormack-Lehane grade I or II view was obtained in 20 (51%) direct laryngoscopies versus 38 (97%) of the video-assisted laryngoscopies (p < 0.01). The median VAS score for difficult airways was 50 mm (IQR = 28–73 mm) for direct versus 18 mm (IQR = 9–50 mm) for video (p < 0.01). The median time to intubation in difficult airways was 25 seconds (IQR = 16–44 seconds) for direct versus 20 seconds (IQR = 12–35 seconds) for video laryngoscopy (p < 0.01). All intubations were successful without need for an invasive airway.

CONCLUSIONS

In this simulation, video laryngoscopy was associated with improved glottic exposure, was perceived as easier, and was slightly faster than conventional direct laryngoscopy in a simulated difficult airway. Absence of secretions and blood limits the generalizability of our findings; human studies are needed.

Video-laryngoscopes in the adult airway management: a topical review of the literature

The aim of the present paper is to review the literature regarding video-laryngoscopes (Storz V-Mac and C-Mac, Glidescope, McGrath, Pentax-Airway Scope, Airtraq and Bullard) and discuss their clinical role in airway management. Video-laryngoscopes are new intubation devices, which provide an indirect view of the upper airway. In difficult airway management, they improve Cormack-Lehane grade and achieve the same or a higher intubation success rate in less time, compared with direct laryngoscopes. Despite the very good visualization of the glottis, the insertion and advancement of the endotracheal tube with video-laryngoscopes may occasionally fail. Each particular device's features may offer advantages or disadvantages, depending on the situation the anaesthesiologist has to deal with. So far, there is inconclusive evidence indicating that video-laryngoscopy should replace direct laryngoscopy in patients with normal or difficult airways.

Comparison of the GlideScope Videolaryngoscope to the standard Macintosh for intubation by pediatric residents in simulated child airway scenarios

OBJECTIVES

Videolaryngoscopy may facilitate tracheal intubation in difficult airway scenarios. Our objective was to compare the ability of residents to intubate a child manikin using the standard Macintosh laryngoscope and the novel GlideScope.

METHODS

Pediatric residents who passed an advanced pediatric life support course were eligible. Four scenarios were proposed: Macintosh (M) and GlideScope (G) "easy" intubation and M and G "difficult"; intubation (cervical immobilization with rigid collar). No participant had previous experience with videolaryngoscope. Each participant performed the 4 scenarios in a random sequence. Time from initiation of intubation procedure to inflation of manikin's chest was recorded, as well as the number of intubation attempts, number of additional maneuvers, dental injury index, and participant's subjective impression.

RESULTS

Eighteen subjects were included. Median (range) time for easy airway intubation was 18 seconds (8-120 seconds) with M versus 37 seconds (18-96 seconds) with G (P = 0.029). Time for intubation with cervical immobilization was 19 seconds (9-120 seconds) with M versus 49 seconds (22-120 seconds) with G (P = 0.006). The G intubation in case of cervical immobilization needed significantly more maneuvers than with the M intubation (P = 0.014). There were no significant differences when number of attempts, dental injury index, and participant's subjective difficulty rate were compared.

CONCLUSIONS

Without specific training, videolaryngoscope-guided intubation did not improve intubation performance by pediatric residents in this manikin model of normal and simulated difficult intubation caused by a cervical collar in place. To achieve skills with videolaryngoscope intubation in children, a specific training program is needed.

Recent advance in patient monitoring

Recent advance in technology has developed a lot of new aspects of clinical monitoring. We can monitor sedation levels during anesthesia using various electroencephalographic (EEG) indices, while it is still not useful for anesthesia depth monitoring. Some attempts are made to monitor the changes in sympathetic nerve activity as one of the indicators of stress, pain/analgesia, or anesthesia. To know the balance of sympathetic and parasympathetic activity, heart rate or blood pressure variability is investigated. For trend of cardiac output, low invasive monitors have been investigated. Improvement of ultrasound enables us to see cardiac structure and function continuously and clearer, increases success rate and decreases complication of central venous puncture and various kinds of nerve blocks. Without inserting an arterial catheter, trends of arterial oxygen tension or carbon dioxide tension can be monitored. Indirect visualization of the airway decreases difficult intubation and makes it easier to teach tracheal intubation. The changes in blood volume can be speculated non-invasively. Cerebral perfusion and metabolism are not ordinary monitored yet, but some studies show their usefulness in management of critically ill. This review introduces recent advances in various monitors used in anesthesia and critical care including some studies of the author, especially focused on EEG and cardiac output. However, the most important is that these new monitors are not almighty but should be used adequately in a limited situation where their meaning is confirmed.

Tracheal intubation using Macintosh and 2 video laryngoscopes with and without chest compressions

PURPOSE

The aim of the study was to compare the time taken for intubation (TTI) using the Macintosh and 2 video laryngoscopes (VLs) (GlideScope [GVL]; Saturn Biomedical System, Burnaby, British Columbia, Canada, and Airway Scope [AWS]; Pentax, Tokyo, Japan) with and without chest compressions by experienced intubators in a mannequin model.

METHODS

This was a randomized crossover study. Twenty-two experienced physicians who have limited experience in the VLs participated in the study. The TTI using 3 laryngoscopes with and without compressions were compared.

RESULTS

Median TTI difference between 2 conditions was only significant in the AWS (1.64 seconds; P = .01). There were no significant differences in the TTI between the Macintosh and the GVL or the AWS during compressions.

CONCLUSION

In a mannequin model, the Macintosh or the GVL was not affected by chest compressions. The TTI using the AWS was delayed by compressions but not clinically significant. Considering the lack of experience, 2 VLs may be useful adjuncts for intubation by experienced intubators during chest compressions.

Comparison of the clinical use of macintosh and miller laryngoscopes for orotracheal intubation by second-month nurse students in anesthesiology

Aim. The aim of this study is to compare the clinical feasibility of Macintosh and Miller laryngoscopes for tracheal intubation in non-experienced users in anesthetized patients. Patients and Methods. 119 patients were randomized into the Macintosh group (59) and the Miller group (60). The primary outcome variable was successful tracheal intubation. The secondary outcome variables were number of insertion attempt, intubation time needed, total time to intubation, hemodynamic change and complications. Results. All patients were successfully intubated using the Macintosh, whereas 13 patients (21.6%) were failed with the Miller (P < .001). The Macintosh significantly reduced the mean total time to intubation (P < .001). There were significant differences in the mean blood pressure at 2 minutes after laryngoscope insertion, immediately, and 2 minutes after tracheal intubation and in the mean heart rate at the laryngoscope insertion, immediately, and at 2 minutes after tracheal intubation between the two groups. Overall complications in both were not significantly different. Conclusion. Orotracheal intubation using the Macintosh is an effective and safe technique in non-experienced hands with significantly increased success rate as well as decreased mean total time to intubation as compare to the Miller. However, these intubations only apply to selected patients deemed to have normal airways.