Simulated Difficult Intubation Research Articles

GlideScope Provides Better Glottic Views Than Direct Laryngoscopy

Glottic view (Cormack-Lehane grade I vs. grade II) was better with the GlideScope than with direct laryngoscopy overall (relative risk, 2.0) and for nondifficult intubations (RR, 1.5) and simulated difficult intubations (manual in-line stabilization; RR, 3.5). Among nonexpert operators, the rate of first-attempt intubation success was higher (RR, 1.8), and intubation time was faster (weighted mean difference, 43 seconds) with the GlideScope than with direct laryngoscopy; no success or time differences were observed among expert intubators. Comment: Glottic visualization was better with the GlideScope than direct laryngoscopy, especially for patients with simulated difficult airways. Nonexpert operators likely had faster and more-successful intubations with the GlideScope because the GlideScope technique is easier to master than direct laryngoscopy. This meta-analysis provides yet another convincing piece of evidence supporting use of video laryngoscopy over conventional direct laryngoscopy.

Glidescope guided intubation: Comparison of Frova introducer, GlideRite Rigid, GlideRite Auto and Truphatek Truflex stylets in a simulated difficult intubation

Glidescope guided intubation: Comparison of Frova introducer, GlideRite Rigid, GlideRite Auto and Truphatek Truflex stylets in a simulated difficult intubation

Comparison of the GlideScope Videolaryngoscope to the Standard Macintosh for Intubation by Pediatric Residents in Simulated Child Airway Scenarios

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. 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. 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. 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.

Response to – comments on comparison of Bonfils fiberscope‐assisted laryngoscopy with standard direct laryngoscopy in simulated difficult pediatric intubation

Response to – comments on comparison of Bonfils fiberscope‐assisted laryngoscopy with standard direct laryngoscopy in simulated difficult pediatric intubation

Comments on comparison of Bonfils fiberscope‐assisted laryngoscopy with standard direct laryngoscopy in simulated difficult pediatric intubation

Comments on comparison of Bonfils fiberscope‐assisted laryngoscopy with standard direct laryngoscopy in simulated difficult pediatric intubation

Manikin study of fibreoptic‐guided intubation through the classic laryngeal mask airway with the Aintree intubating catheter vs the intubating laryngeal mask airway in the simulated difficult airway*

In this randomised crossover manikin study of simulated difficult intubation, 26 anaesthetists attempted to intubate the trachea using two fibreoptic-guided techniques: via a classic laryngeal mask airway using an Aintree intubating catheter and via an intubating laryngeal mask airway using its tracheal tube. Successful intubation was the primary endpoint, which was completed successfully in all 26 cases using the former technique, and in 5 of 26 cases using the latter (p < 0.0001). The former technique also proved quicker to reach the vocal cords with the fibrescope (median (IQR [range])) time 18 (14-20 [8-44]) s vs 110 (70-114 [30-118]) s, respectively; p = 0.008); and to first ventilation (93 (74-109 [52-135]) s vs 135 (79-158 [70-160]) s, respectively; p = 0.0038)]. We conclude that in simulated difficult intubation, fibreoptic intubation appears easier to achieve using a classic laryngeal mask airway and an Aintree intubating catheter than through an intubating laryngeal mask airway.

Comparison of the Pentax AWS videolaryngoscope with the Macintosh laryngoscope in simulated difficult airway intubations by emergency physicians

Objectives The aim of this study was to evaluate the Pentax AWS videolaryngoscope (PAV) in intubation of simulated difficult airways by emergency medical staff. Methods Emergency medical staff and students attempted to intubate a manikin using 3 difficult airways settings with both the PAV and a Macintosh (MAC) laryngoscope in a randomized order. The success of tracheal intubation, time required, number of attempts, airway adjunct use, grade of view obtained, and participant comments were recorded. Results Significantly higher success rates of intubation occurred with the PAV compared with the MAC, irrespective of the level of training or number of previous intubations. With the highest difficulty setting, success occurred in 76.4% with the PAV versus 8.8% with the MAC. The PAV also significantly improved the Cormack and Lehane grading and reduced airway adjunct use, number of intubation attempts, and damage during intubation. Conclusions The PAV may be a useful adjunct in difficult intubations by emergency medical staff.

A comparison of bonfils fiberscope-assisted laryngoscopy and standard direct laryngoscopy in simulated difficult pediatric intubation: a manikin study

Difficult airway management in children is challenging. One alternative device to the gold standard of direct laryngoscopy is the STORZ Bonfils fiberscope (Karl Storz Endoscopy, Tuttlingen, Germany), a rigid fiberoptic stylette-like scope with a curved tip. Although results in adults have been encouraging, reports regarding its use in children have been conflicting. We compared the effectiveness of a standard laryngoscope to the Bonfils fiberscope in a simulated difficult infant airway. Ten pediatric anesthesiologists were recruited for this study and asked to perform three sets of tasks. For the first task, each participant intubated an unaltered manikin (SimBaby (TM), Laerdal, Puchheim, Germany) five times using a styletted 3.5 endotracheal tube (ETT) and a Miller 1 blade (group DL-Normal). For the second task, a difficult airway configuration simulating a Cormack-Lehane grade 3B view was created by fixing a Miller-1 blade into position in the manikin using a laboratory stand. Each participant then intubated the manikin five times with a styletted 3.5 ETT using conventional technique but without touching the laryngoscope (group DL-Difficult). In the third task, the manikin was kept in the same difficult airway configuration, and each participant intubated the manikin five times using a 3.5-mm ETT mounted on the Bonfils fiberscope as an adjunct to direct laryngoscopy with the Miller-1 blade (group BF-Difficult). Primary outcomes were time to intubate and success rate. A total of 150 intubations were performed. Correct ETT placement was achieved in 100% of attempts in group DL-Normal, 90% of attempts in group DL-Difficult and 98% of attempts in BF-Difficult. Time to intubate averaged 14 s (interquartile range 12-16) in group DL-Normal; 12 s (10-15) in group DL-Difficult; and 11 s (10-18) in group BF-Difficult. The percentage of glottic opening seen (POGO score) was 70% (70-80) in group DL-Normal; 0% (0-0) in group DL-Difficult; and 100% (100-100) in group BF-Difficult. The Bonfils fiberscope-assisted laryngoscopy was easier to use and provided a better view of the larynx than simple direct laryngoscopy in the simulated difficult pediatric airway, but intubation success rate and time to intubate were not improved. Further studies of the Bonfils fibrescope as a pediatric airway adjunct are needed.

Performance des glottiscopes : une étude comparative randomisée menée sur simulateur d’intubation difficile

IntroductionWe have prospectively compared simulated-difficult tracheal intubation characteristics of four glottiscopes: Airtraq™, GlideScope™, McGrath™, LMA CTrach™ with that of the conventional Macintosh laryngoscope. Study designprospective with the airway devices proposed in a randomly assigned order. Materials and methodForty-two physicians, naïve to glottiscope handling accepted participating this study after the learning curve of each airway device was completed. Participants were requested to perform two series of five tracheal intubations on the manikin Airman™, the first in standard situation and the second in difficult tracheal intubation simulation. The airway devices were chosen in a randomly assigned order. For each airway tool, the following tracheal intubation characteristics were recorded: laryngeal exposure quality, tracheal intubation and apnea durations. A performance index was calculated and a tracheal intubation difficulty was measured during simulation. ResultsMore than 1600 supervised tracheal intubations were performed, including 1000 for the learning process of the glottiscopes, which was completed after 10 uses on the manikin. During standard situation, laryngeal exposure quality was similar with the five airway devices. As compared to the Macintosh laryngoscope, GlideScope™, McGrath™, tracheal intubation duration was shorter (p<0.05) with the Airtraq™ and longer (p<0.01) with the LMA CTrach™. During difficult tracheal intubation simulation, laryngeal exposure and tracheal intubation duration was of better quality and shorter with the four glottiscopes as compared to that of LM, respectively. Performance index during difficult tracheal intubation simulation simulation was significantly more important (p<0.01) with the Airtraq™ and the LMA CTrach™. Airtraq™ and Macintosh laryngoscope were respectively the simplest (p<0.01) and the most difficult (p<0.01) airway devices to manage a simulated difficult tracheal intubation. ConclusionWhen difficult airway was simulated on the manikin, the four glottiscopes were superior to the Macintosh laryngoscope to improve laryngeal exposure quality and to reduce duration of tracheal intubation. Airtraq™ and the LMA CTrach™ both demonstrated remarkable advantage over GlideScope™ and McGrath™ for simulated difficult intubation management.

Success Rate of Orotracheal Intubation via GlideScope®versus Direct Laryngoscopy in Manikin-Only–Trained Medical Personnel

In Reply:— We thank Dr. Dupanovic for his comments regarding our article, giving us the opportunity to point out some important questions in this field of research.1First, Dr. Dupanovic states that our results appear surprising, with an intubation success rate of about 50% for the conventional technique with a Macintosh blade and about 90% with the GlideScope (Verathon Medical Europe, Ijsselstein, Netherlands). However, when you compare our results with other studies looking at the success rate of intubation performed by medical personnel intubate only occasionally, or in novices of tracheal intubation, these results are very similar.2–5Second, according to Mulcaster et al. 6manikin-only training is inadequate for learning tracheal intubation properly, and the step from manikin intubation to intubation of patients makes a major difference. We totally agree. That is exactly the point where difficulties for the inexperienced operators occurred. They had to deal with airways that differed from patient to patient, and they had to overcome their reluctance to use the necessary force to lift the laryngoscope against the resistance of the soft tissue. At this early step of training, the novices felt much more comfortable and had a higher success rate with the GlideScope technique.Third, Dr. Dupanovic points out that the operators failed to intubate because they failed to achieve a better view of the glottis. Dr. Dupanovic speculates that they might have benefitted from difficult airway training at the manikin before their first intubation attempts in patients. This might have been true. However, we kept our training close to the present training for paramedics, medical students, or novices in anesthesia. Currently, these training sessions start with normal, “easy” intubation in the manikin and patients and progress to difficult intubation after the students have learned easy intubations. In most training centers, manikins for simulated difficult airway training are not available yet. We share the view that training of simulated difficult intubation before intubation of patients might have changed our results, but that was not our study design. We think it is a good idea to integrate simulated difficult airway training in the upcoming years, even for beginners before intubation of patients.Fourth, the conventional laryngoscope with a Macintosh blade is still the most common approach for tracheal intubation. It is widely available, less expensive, and the maintenance is easier than that of the GlideScope. Therefore, in the near future the GlideScope and comparable devices cannot entirely replace the conventional technique, but can be looked upon as an important alternative technique for expected and unexpected difficult intubations.Finally, the most important question is whether the extensive use of alternative laryngoscopes lead to a deficit in training and skills with the conventional laryngoscope. Dr. Dupanovic states that in the beginning, training with the GlideScope might improve the training with the Macintosh blade because the trainees recognize what they are supposed to see, and the attending anesthesiologist can give more precise directions.However, after the first improvements they might not progress to a level that they might reach if they are solely focused on the conventional technique. Basically, this dilemma is comparable to the situation in obstetrics, where the skills for difficult intubations can hardly be taught because most cesarean deliveries are performed under regional anesthesia; therefore, the residents might not get enough exposure and experience.Overall, we think that for anesthesia residents tracheal intubation with conventional laryngoscopes should still be one of the major skills that have to be learned during residency. It is the obligation of the attending anesthesiologists to ensure that the residents receive enough exposure and expertise under controlled conditions.In contrast, for medical personnel who only perform occasional intubations, often in emergency situations, it is not the place and the time to train difficult airway management with the conventional laryngoscope but to switch to a monitor-assisted device like the GlideScope that has a higher success rate. A success rate of about 50% in rather inexperienced medical personnel is too low to withhold more effective devices, even when their overall training with the conventional laryngoscope might suffer. Therefore, in the setting of the emergency room or in the field in highly equipped ambulance cars, a device like the GlideScope should be available. Future research will show if significant improvements can be made.We thank Dr. Dupanovic for voicing his concerns and pointing out how much is still unclear in this field. We also thank the editor for presenting this important discussion.*Kliniken Essen-Mitte, Essen, Germany. h.groeben@kliniken-essen-mitte.de

A comparison of the new paediatric Glidescope®Cobalt Videolaryngoscope and the conventional laryngoscope in simulated normal and difficult intubation conditions

Introduction: Intubation is the core skill of every anaesthetist [1]. The Royal College of Anaesthetists has expressed concern over the apparent increase in airway problems. The Glidescope® can improve laryngeal view [2,3] in adults but not necessarily the time taken to intubation [3,4]. A new paediatric Glidescope® (GVL) became available in October 2008. Instead of the previous reusable version, GVL® small (weight range 1.5–20 kg) there are now two new disposable blades, GVL® 1 (<3.6kg) and GVL® 2 (1.8–10 kg) for use with the ultraportable Cobalt videobaton1–2. Disposable equipment is preferable as it reduces the risk of infection transmission. We aimed to compare the GVL® 2 with conventional laryngoscopy in a paediatric simulator BabySIM (METI) under both normal and difficult airway conditions. We hypothesised the new Glidescope® would perform as well as the conventional laryngoscope. Methods: Following ethics committee approval and informed consent, subjects were asked to perform four intubations in random order; two under normal and two under difficult airway conditions. For each condition, intubation was performed with a conventional laryngoscope (Miller blade) and a GVL® 2. The primary outcome was time to intubation, defined as time from picking up the laryngoscope until first successful inflation of the lungs. A visual analogue scale (VAS) was used to assess the laryngoscopes for field of view, ease of use, willingness to use in an emergency and overall satisfaction. Results were analysed using a paired t-test. Results: Twenty eight anaesthetists were recruited (18 consultants, 10 trainees). Thirteen had no previous experience with the Glidescope® and 15 had used it less than10 times. Results are shown in Table 1. There was no statistical difference in the time taken for successful intubation between the conventional laryngoscope and Glidescope® although there was a trend towards a longer intubation time with the Glidescope®. Time to successful laryngoscopy was significantly longer for the difficult airway compared to the normal airway with both conventional laryngoscopy (P = 0.001) and the Glidescope® (P = 0.002). Table 1. Time to successful intubation and results of VAS Time to intubation (s) Mean (SD) VAS (0–10) evaluation of laryngoscopes Median (IQR) Normal Difficult Field of view Ease of use Emergency use Overall Conventional 26.3 (11.1) 45.2 (27.5) 8 (6–9) 8 (7–9) 9 (8–10) 8 (8–9) Gildescope® 30.3 (20.0) 50.9 (21.9) 7 (6–9) 8 (7–9) 6 (5–7) 7 (6–8) Discussion: Successful intubation of our simulator manikin under difficult airway conditions was prolonged with both laryngoscopes when compared to normal conditions, suggesting that BabySIM is a useful model for difficult intubation. The Glidescope® performed as well as the conventional laryngoscope however it did not reduce the time to intubation, which is similar to results in adult simulators [3]. Our anaesthetists indicated a preference for conventional laryngoscopy in the emergency setting. This is likely to be due to familiarity with equipment. Conclusion: The Glidescope® performs as well as conventional laryngoscopy for intubation of the BabySIM manikin in both the normal and simulated difficult airway setting.

Comparison of the Glidescope® and Pentax AWS®laryngoscopes to the Macintosh laryngoscope for use by Advanced Paramedics in easy and simulated difficult intubation

BackgroundIntubation of the trachea in the pre-hospital setting may be lifesaving in severely ill and injured patients. However, tracheal intubation is frequently difficult to perform in this challenging environment, is associated with a lower success rate, and failed tracheal intubation constitutes an important cause of morbidity. Novel indirect laryngoscopes, such as the Glidescope® and the AWS® laryngoscopes may reduce this risk.MethodsWe compared the efficacy of these devices to the Macintosh laryngoscope when used by 25 Advanced Paramedics proficient in direct laryngoscopy, in a randomized, controlled, manikin study. Following brief didactic instruction with the Glidescope® and the AWS® laryngoscopes, each participant took turns performing laryngoscopy and intubation with each device, in an easy intubation scenario and following placement of a hard cervical collar, in a SimMan® manikin.ResultsBoth the Glidescope® and the AWS® performed better than the Macintosh, and demonstrate considerable promise in this context. The AWS® had the least number of dental compressions in all three scenarios, and in the cervical spine immobilization scenario it required fewer maneuvers to optimize the view of the glottis.ConclusionThe Glidescope® and AWS® devices possess advantages over the conventional Macintosh laryngoscope when used by Advanced Paramedics in normal and simulated difficult intubation scenarios in this manikin study. Further studies are required to extend these findings to the clinical setting.

Comparison of the Airtraq® and Truview®laryngoscopes to the Macintosh laryngoscope for use by Advanced Paramedics in easy and simulated difficult intubation in manikins

BackgroundParamedics are frequently required to perform tracheal intubation, a potentially life-saving manoeuvre in severely ill patients, in the prehospital setting. However, direct laryngoscopy is often more difficult in this environment, and failed tracheal intubation constitutes an important cause of morbidity. Novel indirect laryngoscopes, such as the Airtraq® and Truview® laryngoscopes may reduce this risk.MethodsWe compared the efficacy of these devices to the Macintosh laryngoscope when used by 21 Paramedics proficient in direct laryngoscopy, in a randomized, controlled, manikin study. Following brief didactic instruction with the Airtraq® and Truview® laryngoscopes, each participant took turns performing laryngoscopy and intubation with each device, in an easy intubation scenario and following placement of a hard cervical collar, in a SimMan® manikin.ResultsThe Airtraq® reduced the number of optimization manoeuvres and reduced the potential for dental trauma when compared to the Macintosh, in both the normal and simulated difficult intubation scenarios. In contrast, the Truview® increased the duration of intubation attempts, and required a greater number of optimization manoeuvres, compared to both the Macintosh and Airtraq® devices.ConclusionThe Airtraq® laryngoscope performed more favourably than the Macintosh and Truview® devices when used by Paramedics in this manikin study. Further studies are required to extend these findings to the clinical setting.

Evaluation of tracheal tube introducers in simulated difficult intubation*

In a randomised cross-over study, 72 anaesthetists attempted to place Pro-Breathe, new Portex, and Frova single-use tracheal tube introducers and an Eschmann multiple-use introducer in the trachea of a manikin set to simulate a grade 3 laryngeal view. Successful placement (proportion, 95% confidence interval) of either the Frova (78%, 67-86%) or the Eschmann introducer (64%, 52-74%) was significantly more likely (p < 0.0001) than with the Pro-Breathe (4%, 1-12%) or the new Portex introducer (13%, 7-22%). The difference between the success rates for the Frova and the Eschmann introducers (p = 0.08) was not significant. A separate experiment revealed that the peak force that could be exerted by the Pro-Breathe, new Portex and Frova single-use introducers were three to six times greater than that which could be exerted by the Eschmann introducer (p < 0.0001). The single-use introducers are more likely to cause tissue trauma during placement, particularly if held close to the tip.

Comparison of the airway scope, Airtraq and Macintosh laryngoscopes in simulated difficult tracheal intubation: A manikin study

Comparison of the airway scope, Airtraq and Macintosh laryngoscopes in simulated difficult tracheal intubation: A manikin study

Malleable stylet vs. re-useable and disposable bougies in a model of difficult intubation: A randomised cross-over trial

Paramedics’ intubation success rates with Cormack and Lehane grade III/IV views have been reported to be 0%. Misplaced tracheal tubes occur in 5.8 to 25% of all pre-hospital intubations: 67 to 75% of these are in the oesophagus. This trial evaluated four adjuncts in a simulated pre-hospital difficult intubation. Pre-hospital laryngoscopists attending the Australian College of Ambulance Professionals (ACAP) conference (September 2007) attempted …

Comparison of the Airway Scope®, gum elastic bougie and fibreoptic bronchoscope in simulated difficult tracheal intubation: a manikin study

We compared the Airway Scope with a gum elastic bougie and fibreoptic bronchoscope in a manikin with a simulated Cormack and Lehane Grade 3 laryngoscopic view. Twenty-seven anaesthetists intubated the trachea of the manikin with these devices and the time required for intubation was measured. They were then asked to rate the subjective difficulty of intubation (1 = very easy; 5 = very difficult). Mean (SD) intubation times were 16.6 (11.2) s with the Airway Scope, 29.4 (10.9) s with the gum elastic bougie (p < 0.0001), and 30.6 (20.0) s with the fibreoptic bronchoscope (p < 0.0001). The median (range) difficulty was 2 (1-4) with the Airway Scope, 3 (2-4) with the gum elastic bougie (p < 0.001), and 2 (1-5) with the fibreoptic bronchoscope (p = 0.014). In Cormack and Lehane grade 3 laryngoscopic views, the Airway Scope may enable faster and easier tracheal intubation than does a Macintosh laryngoscope with a gum elastic bougie or a fibreoptic bronchoscope.

A Comparison of a Fiberoptic Stylet and a Bougie as Adjuncts to Direct Laryngoscopy in a Manikin-Simulated Difficult Airway

We compare the effectiveness of an endotracheal tube introducer ("bougie") with a new fiberoptic stylet as an adjunct to direct laryngoscopy in facilitating simulated difficult tracheal intubation in a manikin. Inexperienced laryngoscopists were recruited for this randomized, crossover study. After brief training, participants were randomized to first use either the bougie or fiberoptic stylet as an adjunct to direct laryngoscopy for attempted tracheal intubation of a manikin presenting a fixed, simulated, Cormack-Lehane grade IIIA view. Two attempts at tracheal intubation were allowed, each limited to 60 seconds. The participant then crossed over and used the other device. The same procedure was then repeated on a second manikin presenting a simulated Cormack-Lehane grade IIIB view. Primary outcomes were time to tracheal intubation and successful endotracheal tube placement. One hundred three study participants performed a total of 533 tracheal intubations for evaluation. For the Cormack-Lehane grade IIIA view, correct placement of the endotracheal tube was achieved in 101 (98%) of the fiberoptic stylet-facilitated and all 103 (100%) of the bougie-facilitated tracheal intubations. The time to successful tracheal intubation was similar for both devices (difference in mean time 1.8 seconds; 95% confidence interval [CI] -2.5 to 6.1 seconds). In the Cormack-Lehane grade IIIB view manikin, use of the fiberoptic stylet significantly increased success rate (fiberoptic stylet 98% versus bougie 9%), and a trend was observed toward a decrease in the mean time required for successful tracheal intubation compared to the bougie (fiberoptic stylet 31.0 seconds versus bougie 45.6 seconds; difference in mean time -14.6 seconds; 95% CI -31.4 to 2.3 seconds). In a manikin model, with inexperienced clinicians, both the bougie and the fiberoptic stylet were effective in facilitating tracheal intubation of a simulated Cormack-Lehane grade IIIA view. For a Cormack-Lehane IIIB view, the fiberoptic stylet was significantly more effective than the bougie in facilitating tracheal intubation. Because a manikin model eliminates some of the barriers to use of fiberoptics in patients, further validation of fiberoptic stylet use is required in human subjects with normal and difficult airways.

Comparison of the shikani optical stylet and the bougie in simulated difficult intubation

Comparison of the shikani optical stylet and the bougie in simulated difficult intubation

Comparison of three video laryngoscopes with Macintosh laryngoscope in simulated difficult intubation: a manikin study

Comparison of three video laryngoscopes with Macintosh laryngoscope in simulated difficult intubation: a manikin study