Evaluation of ease of intubation with the GlideScope�or Macintosh laryngoscope by anaesthetists in simulated easy and difficult laryngoscopy

A comparative study on the usefulness of the Glidescope or Macintosh laryngoscope when intubating normal airways

BACKGROUND

The Glidescope Videolaryngoscope (GVL) is a newly developed video laryngoscope. It offers a significantly improved laryngeal view and facilitates endotracheal intubation in difficult airways, but it is controversial in that it offers an improved laryngeal view in normal airways as well. And the price of GVL is expensive. We hypothesized that intubation carried out by fully experienced anesthesiologists using the GVL with appropriate pre-anesthetic preparations offers an improved laryngeal view and shortened intubation time in normal airways. Therefore, the aim of this study was to compare the GVL with the Macintosh laryngoscope in normal airways and to determine whether GVL can substitute the Macintosh laryngoscope.

METHODS

This study included 60 patients with an ASA physical status of class 1 or 2 requiring tracheal intubation for elective surgery. All patients were randomly allocated into two groups, GVL (group G) or Macintosh (group M). ADS (airway difficulty score) was recorded before induction of anesthesia. The anesthesiologist scored vocal cord visualization using the percentage of glottic opening (POGO) visible and the subjective ease of intubation on a visual analogue scale (VAS). The time required to intubate was recorded by an assistant.

RESULTS

There was a significant increase in POGO when using the GVL (P < 0.05). However, there was no difference in the time required for a successful tracheal intubation using the GVL compared with the Macintosh laryngoscope. The VAS score on the ease of intubation was significantly lower for the GVL than for the Macintosh laryngoscope (P < 0.05).

CONCLUSIONS

GVL could be a first-line tool in normal airways.

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.

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.

[Faster double-lumen tube intubation with the videolaryngoscope than with a standard laryngoscope]

PURPOSE

This study was designed to compare videolaryngoscopy with direct laryngoscopy with respect to ease of intubation when inserting a double lumen tube (DLT).

METHODS

In this prospective randomized study 68 patients American Society of Anesthesiologists (ASA) physical status I and II were included. Patients with criteria indicating possible difficult intubation were excluded. The patients were randomized into two groups, depending on the tool used to facilitate intubation: videolaryngoscope (VL group) or direct laryngoscopy (DL group). The time required for intubation was the primary endpoint. Cormack and Lehane glottic visualization (CL) scores, the need for external laryngeal maneuvers and the number of attempts were measured.

RESULTS

Glottic visualization was better in the VL group than in the DL group. The CL scores were I, II and III in 24, eight and two patients, respectively, in the VL group compared with 13, 11 and eight in the DL group (P = 0.025). Patients in the VL group required fewer attempts than the DL group (P = 0.019). Intubation time was 39.9 ± 4.4 sec in the VL group and 47.9 ± 5.4 sec in the DL group (P < 0.001). No intubation failure was noted in group VL compared with two in the DL group (not significant).

CONCLUSION

The use of a videolaryngoscope reduces the time required for intubation with a DLT compared with the direct laryngoscopy in elective thoracic surgery.

Advances in laryngoscopy: rigid indirect laryngoscopy

There is a growing body of evidence to support the use of rigid indirect laryngoscopy or 'video' laryngoscopy for tracheal intubation. We summarise some of the key issues, comparing rigid indirect laryngoscopy with direct conventional laryngoscopy.

A comparison of Bonfils intubation fiberscopy and fiberoptic bronchoscopy in difficult airways assisted with direct laryngoscopy

Background

To evaluate the usefulness of Bonfils intubation fiberscope assisted by direct laryngoscopy (BIF-DL) and flexible fiberoptic bronchoscope assisted by direct laryngoscopy (FOB-DL) using video recording in cases of unanticipated difficult intubation with respect to the time required to visualize the vocal cords and place the endotracheal tube. We compared two fiberscopes in patients with authentic difficult airways.

Methods

In this randomized, controlled clinical trial, 40 patients (grade 3 according to grades of difficulty in laryngoscopy), scheduled for surgery under general anesthesia were randomly allocated to BIF-DL group or FOB-DL group. Number of attempts, time required for visualization of the vocal cord (T1) and placement of the endotracheal tube (T2) from insertion of instrument during the last successful attempt, and duration of scope manipulation during all attempts (T_total) were recorded. If intubation failed with one method, the other method was tried; these cases were then excluded. The incidence of sore throat and hoarseness was assessed.

Results

T1, T2, and T_total were significantly shorter in BIF-DL group (T1: 21.9 ± 8.2 sec vs. 80.4 ± 29.9 sec, P < 0.001, T_total: 77.9 ± 41.2 sec vs. 145.5 ± 83.9 sec, P = 0.003). In two cases, it was impossible to intubate with BIF-DL, but the procedure was subsequently successful using fibreoptic bronchoscope.

Conclusions

Intubation of difficult airways can be performed more rapidly with BIF-DL, but sometimes it may not be possible to intubate with the scope.

Patient- and operator-related factors associated with successful Glidescope intubations: a prospective observational study in 742 patients

The Glidescope Video Laryngoscope (Glidescope, Verathon Medical, Bothell, WA, U.S.A.) is a relatively new intubating device. It has been proposed to be useful for securing both routine airways and those where direct laryngoscopy may be difficult. In this prospective observational study, data for 742 intubations using the Glidescope were collected to investigate whether four factors are associated with successful tracheal intubation at first attempt using the Glidescope: previous Glidescope experience, previous direct laryngoscopy experience, level of anaesthesia training and clinical airway assessment. The likelihood of successful tracheal intubation at first attempt using the Glidescope increased with increasing previous Glidescope experience. Similarly, success was more likely in airways that were assessed as normal compared with those where direct laryngoscopies were either predicted or known to be difficult. Subgroup analysis indicated 83% first attempt success by 'experienced' Glidescope users in patients with documented difficult direct laryngoscopies. This supports its use as an adjunct device for management of airways where direct laryngoscopies prove difficult. With regard to the level of anaesthesia training, only medical students were more likely to fail with the Glidescope. Success was not associated with previous experience in direct laryngoscopy. The lack of association with direct laryngoscopy experience and level of anaesthesia training (beyond student level) suggests that expertise with traditional airway tools is not necessary to become proficient with the Glidescope.

Comparison of the Cobalt Glidescope video laryngoscope with conventional laryngoscopy in simulated normal and difficult infant airways

AIM

To evaluate the new pediatric Glidescope (Cobalt GVL Stat) by assessing the time taken to tracheal intubation under normal and difficult intubation conditions. We hypothesized that the Glidescope would perform as well as conventional laryngoscopy.

BACKGROUND

A new pediatric Glidescope became available in October 2008. It combines a disposable, sterile laryngoscope blade and a reusable video baton. It is narrower and longer than the previous version and is available in a greater range of sizes more appropriate to pediatric use.

METHODS

We performed a randomized study of 32 pediatric anesthetists and intensivists to compare the Cobalt GVL Stat with the Miller laryngoscope under simulated normal and difficult airway conditions in a pediatric manikin.

RESULTS

We found no difference in time taken to tracheal intubation using the Glidescope or Miller laryngoscope under normal (29.3 vs 26.2 s, P = 0.36) or difficult (45.8 and 44.4 s, P = 0.84) conditions. Subjective evaluation of devices for field of view (excellent: 59% vs 53%) and ease of use (excellent: 69% vs 63%) was similar for the Miller laryngoscope and Glidescope, respectively. However, only 34% of participants said that they would definitely use the Glidescope in an emergency compared with 66% who would be willing to use the Miller laryngoscope.

CONCLUSIONS

The new Glidescope performs as well as the Miller laryngoscope under simulated normal and difficult airway conditions.

Comparison of a single-use GlideScope Cobalt videolaryngoscope with a conventional GlideScope for orotracheal intubation

BACKGROUND

This study was conceived to compare the single-use GlideScope Cobalt videolaryngoscope with the conventional GlideScope videolaryngoscope for orotracheal intubation, as judged by time to intubation (TTI) and ease of intubation.

METHODS

One hundred patients with normal-appearing airways requiring orotracheal intubation for elective surgery were randomly allocated to have their tracheas intubated by a heterogeneous group of operators with the Cobalt GlideScope or the conventional GlideScope. TTI was assessed by a blinded observer. Operators were blinded until the start of laryngoscopy. A visual analogue scale (VAS) assessed the ease of intubation. The number of intubation attempts, number of failures, glottic grades, and fogging of the video screen were recorded.

RESULTS

There was no difference between the median TTI of the GlideScope Cobalt and the conventional GlideScope (40.1 sec, interquartile range [IQR] 34.1, 51.3 vs 39 sec, IQR 32.6, 48.1, respectively; P = 0.75). The ease of intubation was similar between the two devices (median Cobalt VAS: 16 mm, IQR 10.8, 27.3, vs median conventional VAS: 12.5 mm, IQR 10, 20.5, respectively; P = 0.12). There were no significant differences between the two devices with respect to glottic exposure, intubation attempts, failures, or video screen fogging.

CONCLUSIONS

The GlideScope Cobalt has similar performance characteristics compared with the conventional GlideScope videolaryngoscope when used for orotracheal intubation. The two devices can likely be used interchangeably. (ClinicalTrials.gov number, NCT00459797.).

Fracture of a GlideScope® Cobalt GVL® Stat disposable blade during an emergency intubation

BACKGROUND

Emergency airway management is a diverse discipline, often utilizing advanced equipment with video technology to enable the intubator to visualize a patient's vocal cords that would be difficult or impossible to see with routine direct laryngoscopy. The GlideScope® Cobalt (Saturn Biomedical Systems, Inc., Burnaby, BC, Canada) is one type of video laryngoscope with disposable plastic GVL® Stat blades (Saturn Biomedical Systems) that can improve glottic view over direct laryngoscopy. It also benefits from rapid turnaround time and few infection control issues due to its disposable blade.

OBJECTIVE

To report what we believe to be the first GlideScope® blade failure to be reported in the medical literature. The circumstances surrounding the blade failure may raise awareness of GVL® Stat usage in obese patients with limited mouth opening.

CASE REPORT

During a standard emergency intubation, insertion of the GVL® Stat into the patient's mouth resulted in breakage of the distal segment of the blade. The patient was severely obese and had limited mouth opening, which required the blade to be inserted obliquely, rather than in the midline, into the patient's mouth. As the handle was repositioned back to midline, the distal segment of the blade broke off. No excessive force was used during blade repositioning when breakage occurred.

CONCLUSION

Twisting forces on the distal flat segment of the GVL® Stat may have caused its failure. Because this was only a single occurrence of breakage, it is not clear if design issues or atypical insertion of the blade was responsible for breakage. Care must be exercised when midline insertion is not possible, which can occur in obese patients with limited mouth opening.

Utilization of a Glidescope videolaryngoscope for orotracheal intubations in different emergency airway management settings

OBJECTIVE

To describe the initial experience of a group of emergency department (ED) physicians, utilizing a Glidescope videolaryngoscope (GVL) for orotracheal intubations in the ED.

METHODOLOGY

A 6-month, single center, prospective observational study from 19 Feb 2007 to 18 Aug 2007 was conducted on all orotracheal intubations, which involved utilization of the original GVL in different emergency airway management scenarios.

RESULTS

Overall success of GVL intubation was 15 out of 21 (71.4%) cases. The GVL was able to provide at least Cormack-Lehane grade I or II laryngoscopy views in all cases. All the operators highlighted difficulty in angulating and maneuvering the endotracheal tube for insertion through the glottis as the primary difficulty encountered.

CONCLUSION

We found the GVL to be an effective device in our ED's emergency airway control repertoire. Its role in the anticipated difficult airway in the ED will need further studies.

Video and optic laryngoscopy assisted tracheal intubation--the new era

With advances in technology, videoscopy and optic intubation have been gaining popularity particularly in patients with difficult airways or as rescue devices in failed intubation attempts. Their routine use is, however an uncommon occurrence. This review paper will summarise some of those newly developed devices currently available to assist tracheal intubation, their advantages, disadvantages when compared with the conventional laryngoscope and finally, evidence to support their use in both elective and emergency airway management.

Tracheal intubating conditions using propofol and remifentanil target-controlled infusion: a comparison of remifentanil EC50 for Glidescope and Macintosh

BACKGROUND AND OBJECTIVE

The combination remifentanil-propofol was used for tracheal intubation without muscle relaxant in patients with anticipated difficult airway. Using a target-controlled infusion, we compared the remifentanil concentrations required for intubation with the Macintosh laryngoscope and the Glidescope, at a constant plasma concentration of propofol without muscle relaxant.

METHODS

Sixty ASA I or II patients were randomly assigned to either the Macintosh or Glidescope group (30 per group). A target-controlled infusion of propofol was used to maintain a predetermined effect-site concentration of 3 microg ml. The target concentration of remifentanil for each patient in a group was determined by the response of the previous patient, using increments or decrements of 0.5 ng ml. Intubation was attempted at 4 min following induction to allow for equilibration between the blood and the effect site. The intubation response was graded as successful or failure by the Helbo-Hansen scoring system. The median effective concentration of remifentanil for tracheal intubation was determined using the probit regression model.

RESULTS

The median effective concentration of remifentanil required for intubation with the Macintosh laryngoscope was 4.41 ng ml (3.13-5.27; 95% confidence interval) and that of the Glidescope was 5.45 ng ml (4.45-6.45; 95% confidence interval; P = 0.083). There was no difference in the total intubation scores. No patients showed signs of muscle rigidity. Arterial pressures or heart rate did not differ between the groups.

CONCLUSION

There is no strong evidence that the target remifentanil concentrations required for adequate intubating conditions differed according to the technique used for intubation in the nonparalysed patient. We did not detect any major complications using this technique for either method.

Videolaryngoscopy in the management of the difficult airway: a comparison with the Macintosh blade

BACKGROUND AND OBJECTIVE

Several studies have shown that videolaryngoscopes can provide better laryngeal exposure than conventional laryngoscopy. These studies, however, did not exclusively focus on patients with an anticipated difficult intubation. The aim of the present study was to assess whether a videolaryngoscope would provide better laryngeal exposure than conventional laryngoscopy and therefore facilitate intubation in cases of difficult laryngoscopy.

METHODS

One hundred and twelve patients with an estimated difficult intubation, scheduled to undergo surgical operations, requiring general anaesthesia and endotracheal intubation, were included in the study. Direct laryngoscopy with a Macintosh blade was performed, followed by videolaryngoscopy and intubation attempt(s). The laryngeal views obtained by each method were recorded according to the Cormack/Lehane scale.

RESULTS

The percentage of Cormack-Lehane I and II views obtained by conventional laryngoscopy rose from 63.4 to 90.2% (P < 0.0005) with videolaryngoscopy, whereas Cormack-Lehane III and IV views declined from 36.6 to 9.8% (P < 0.0005). Intubation was successful in 98.2% of the cases.

CONCLUSION

In patients with an anticipated difficult airway, videolaryngoscopy significantly improved the laryngeal exposure thus facilitating endotracheal intubation.

Expected difficult tracheal intubation: a prospective comparison of direct laryngoscopy and video laryngoscopy in 200 patients

BACKGROUND

The Berci-Kaplan video laryngoscope was developed to improve the visualization of the glottis and ease tracheal intubation. Whether this technique is also effective in patients with an expected difficult intubation is unclear. We have prospectively evaluated the conditions and success rate of tracheal intubation in patients with a Mallampati score of III or IV.

METHODS

Two hundred patients, undergoing general anaesthesia, were randomized to be intubated using direct laryngoscopy (n=100) or video laryngoscopy (n=100). Visualization of the vocal cords, success rate, time for intubation, and the need for additional manoeuvres (laryngeal manipulations, head positioning, and Eschmann stylet) were evaluated.

RESULTS

Video laryngoscopy produced better results for the visualization of the glottis using Cormack and Lehane criteria (P<0.001), success rate (n=92 vs 99, P=0.017), and the time for intubation [60 (77) vs 40 (31) s, P=0.0173]. In addition, the number of optimizing manoeuvres was also significantly decreased [1.2 (1.3) vs 0.5 (0.7), P<0.001].

CONCLUSIONS

Video laryngoscopy, when compared with direct laryngoscopy for difficult intubations, provides a significantly better view of the cords, a higher success rate, faster intubations, and less need for optimizing manoeuvres. Therefore, we feel that the video laryngoscopy leads to a clinically relevant improvement of intubation conditions and can be recommended for difficult airway management.

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

SUMMARY

Several indirect laryngoscopes have recently been developed, but relatively few have been formally compared. In this study we evaluated the efficacy and the usability of the Macintosh, the Glidescope, the McGrath and the Airtraq laryngoscopes. Sixty anaesthesia providers (20 staff, 20 residents, and 20 nurses) were enrolled into this study. The volunteers intubated the trachea of a Laerdal SimMan manikin in three simulated difficult airway scenarios. In all scenarios, indirect laryngoscopes provided better laryngeal exposure than the Macintosh blade and appeared to produce less dental trauma. In the most difficult scenario (tongue oedema), the Macintosh blade was associated with a high rate of failure and prolonged intubation times whereas indirect laryngoscopes improved intubation time and rarely failed. Indirect laryngoscopes were judged easier to use than the Macintosh. Differences existed between indirect devices. The Airtraq consistently provided the most rapid intubation. Laryngeal grade views were superior with the Airtraq and McGrath than with the Glidescope.

Developing technical expertise in emergency medicine--the role of simulation in procedural skill acquisition

Developing technical expertise in medical procedures is an integral component of emergency medicine (EM) practice and training. This article is the work of an expert panel composed of members from the Society for Academic Emergency Medicine (SAEM) Interest Group, the SAEM Technology in Medical Education Committee, and opinions derived from the May 2008 Academic Emergency Medicine Consensus Conference, "The Science of Simulation in Healthcare." The writing group reviewed the simulation literature on procedures germane to EM training, virtual reality training, and instructional learning theory as it pertains to skill acquisition and procedural skills decay. The authors discuss the role of simulation in teaching technical expertise, identify training conditions that lead to effective learning, and provide recommendations for future foci of research.

GlideScope video laryngoscope: a randomized clinical trial in 203 paediatric patients

BACKGROUND

The GlideScope intubating device has been reported to provide a comparable or superior laryngoscopic view compared with direct laryngoscopy in adults. This study compared the use of the GlideScope with direct laryngoscopy for the laryngoscopic view and intubation time in children.

METHODS

The laryngoscopic view in 203 children was scored using both the Macintosh laryngoscope and the GlideScope using Cormack and Lehane (C&L) grades. After scoring each laryngoscopic view with and without BURP, the patients were randomly allocated to two groups. The trachea was intubated using direct laryngoscopy (Group DL, n=100) or the GlideScope (Group GS, n=103). We compared C&L grades for the two views in the same patient, and also the time to intubate for each group.

RESULTS

The GlideScope improved the view without BURP in the patients with C&L grade 2 (16/26, P<0.01) and with C&L grades 3 and 4 (7/11, P<0.05). The view with BURP was also improved by the GlideScope in C&L grade 2 (4/9, P<0.05) and with C&L grades 3 and 4 (4/5, P=0.059). The mean time for tracheal intubation was 36.0 (17.9) s in the GS group and 23.8 (13.9) s in the DL group (P<0.001).

CONCLUSIONS

In children, the GlideScope provided a laryngoscopic view equal to or better than that of direct laryngoscopy but required a longer time for intubation.

Optical and video laryngoscopes for emergency airway management

Direct laryngoscopy for airway management was introduced into clinical medicine almost 70 years ago and is still the dominant modality. The recent development of video and optical laryngoscopy could be the most important change in this paradigm. This paper examines state of the art devices and makes recommendations regarding specific advantages they advance for the field of emergency medicine.

The GlideScope-specific rigid stylet and standard malleable stylet are equally effective for GlideScope use

PURPOSE

The GlideScope videolaryngoscope usually provides excellent glottic visualization, but directing an endotracheal tube (ETT) through the vocal cords can be challenging. The goal of the study was to compare the dedicated GlideScope-specific rigid stylet to the standard malleable stylet, assessed by time to intubation (TTI).

METHODS

Eighty patients requiring orotracheal intubation for elective surgery were randomly allocated to either the GlideScope rigid stylet (GRS) or a standard malleable stylet to facilitate intubation using the GlideScope. Time to intubation was recorded by blinded assessors; operators were blinded until after laryngoscopy. The operator assessed the ease of intubation using a visual analogue scale (VAS). The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were documented.

RESULTS

The median TTI was 42.7 sec (inter-quartile range (IQR) 38.9-56.7) for the GRS group compared to 39.9 sec (IQR 34.1-48.2) for the control group (P=0.07). The median VAS score for ease of intubation was 20 (IQR 12.0-33.0) for the GRS group compared to 18 (IQR 9.5-29.5) for the control group (P=0.21). There was no significant difference in TTI or VAS between stylets. The overall incidence of a Cormack-Lehane grade I or II glottic view was 98%.

CONCLUSIONS

In a group of experienced operators using the GlideScope, the dedicated GRS and the standard malleable ETT stylet are equally effective in facilitating endotracheal intubation.

Airway Management in Trauma: An Update

This article reviews the more recent theoretic and practical information that pertains to airway management in the trauma setting. This is followed by a presentation of the newer airway devices that may be advantageous in the management of the airway in trauma as well as a discussion of other devices, techniques, or maneuvers that are useful in the trauma setting but may be underused. Each clinician needs to be knowledgeable about the various airway options and then, based on one's own particular skills and resources, construct an airway management algorithm that works best for him or her. Each clinician needs to be knowledgeable about the various airway options, and then, based on the clinician's particular skills and resources, construct an airway management algorithm that works best.

Case series: the McGrath videolaryngoscope--an initial clinical evaluation

PURPOSE

To document tracheal intubation success rates and airway instrumentation times using the newly designed McGrath videolaryngoscope.

METHODS

We prospectively recorded factors associated with difficult tracheal intubation, factors causing actual difficulty in tracheal intubation, as well as complications arising from use of the new McGrath videolaryngoscope in a series of adult patients with normal preoperative airway examinations. All patients were undergoing scheduled or elective surgery. In the first 75 patients (phase I), experience with airway instrumentation was documented, while in the second 75 patients (phase II), the time required to obtain an optimal view of the larynx was recorded, as well as the time to complete tracheal intubation.

RESULTS

Ninety-eight percent of all tracheal intubations were successful using the McGrath videolaryngoscope. Cormack and Lehane grade I views were obtained in 143 patients (95%) and grade II views were achieved in six (4%). In phase II, the median time required to obtain an adequate view was 6.3 sec [interquartile range 4.7-8.7 (range 2-26.3)], and to complete tracheal intubation was 24.7 sec [18.5-34.4 (11.4-286)]. Fortynine (65%) of the tracheal intubations were completed within 30 sec, and 72 (96%) were completed within one minute. No complications were encountered in any patient.

CONCLUSIONS

The McGrath videolaryngoscope is an effective aid to airway management in patients with normal airways, based upon intubation success rates and the ability to rapidly secure the airway. Its potential advantages of convenience and portability warrant further evaluation in comparison with other airway devices and in patients with difficult airways.

A clinical assessment of the Glidescope videolaryngoscope in nasotracheal intubation with general anesthesia

STUDY OBJECTIVES

To evaluate the efficacy and safety of the Glidescope videolaryngoscope as a device to aid nasotracheal intubation, and to determine whether the GSVL provides a better laryngeal view in patients with difficult laryngoscopy compared with the Macintosh laryngoscope.

DESIGN

Prospective, clinical study.

SETTING

Two university hospitals.

PATIENTS

156 healthy adult ASA physical status I and II undergoing elective plastic and intraoral surgery with general anesthesia.

INTERVENTIONS

After anesthesia induction with intravenous injection of fentanyl 2 microg/kg, propofol 2 mg/kg, and vecuronium 0.1 mg/kg, nasotracheal intubation was performed using GSVL.

MEASUREMENTS

Preoperative airway measurements were taken to predict potential difficult airways. During nasotracheal intubation using GSVL, laryngeal views, times required for full visualization of glottis and successful intubation, difficulty encountered and auxiliary maneuvers adopted, and upper airway trauma were recorded. The laryngeal views obtained by GSVL and by Macintosh laryngoscope were compared.

MAIN RESULTS

The laryngeal views obtained by GSVL in all patients were Cormack and Lehane (C&L) grades I and II, and the success rate of intubation using GSVL at one attempt was 98.1%. The times required for visualization of the glottis and successful intubation were 40.2 +/- 11.5 s and 52.7 +/- 12.3 seconds, respectively. Patients with C&L grade II needed more auxiliary maneuvers to achieve successful intubation than did those with C&L grade I (P < 0.001). In 36 patients with potential difficult airways, the frequency of difficult laryngoscopy (C&L grades III and IV) with the Macintosh laryngoscope (58.3%) was significantly higher than with the GSVL (0%, P < 0.05). The frequency of minor upper airway trauma was 4.5%.

CONCLUSIONS

The GSVL is an effective device for nasotracheal intubation and may be incorporated easily into routine clinical practice. Compared with the Macintosh laryngoscope, the GSVL can provide an improved laryngeal view in the patient with difficult airway.

Effect of stylet angulation and endotracheal tube camber on time to intubation with the GlideScope

PURPOSE

The GlideScope videolaryngoscope usually provides excellent glottic visualization, but directing an endotracheal tube (ETT) through the vocal cords is sometimes difficult. The goal of the study was to determine which of two ETT angles (60 degrees vs 90 degrees ) and cambers (forward vs reverse) was better, as determined by time to intubation (TTI).

METHODS

Two hundred patients requiring orotracheal intubation for elective surgery were randomly allocated to one of four groups: A) 90 degrees angle, forward camber; B) 90 degrees angle, reverse camber; C) 60 degrees angle, forward camber; D) 60 degrees angle, reverse camber. Time to intubation was assessed by a blinded observer. Operators were blinded until the point of intubation. A visual analogue scale (VAS) assessed the ease of intubation. The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were recorded.

RESULTS

The angle of the ETT had an impact on TTI but camber did not. The 90 degrees angle demonstrated a 13% faster TTI than the 60 degrees angle (47.1 +/- 21.2 sec vs 54.4 +/- 28.2 sec, P=0.042), and it resulted in easier intubation (VAS 16.4 +/- 14.2 mm vs 27.3 +/- 23.5 mm, P=0.0001). The overall incidence of a grade 1 or 2 Cormack-Lehane glottic view was 99%.

CONCLUSIONS

In a heterogeneous group of operators and patients intubated with the GlideScope, a 90 degrees ETT angle provided the best result and should be the initial configuration. The camber of the ETT does not affect the time to intubation.

Clinical comparisons between GlideScope® video laryngoscope and Trachlight® in simulated cervical spine instability

STUDY OBJECTIVE

To compare the time taken for tracheal intubation, hemodynamic changes, and perioperative morbidities between the GlideScope (GS) video laryngoscope and the Trachlight (TL) with manual inline stabilization.

DESIGN

Prospective, controlled, randomized study.

SETTING

Operating room.

PATIENTS

60 ASA physical status I and II patients scheduled for elective surgery with general anesthesia.

INTERVENTIONS

Patients were randomly assigned to the GS group or TL group (n = 30 for each group).

MEASUREMENTS

Noninvasive blood pressure and heart rate at preinduction; preintubation and one, three, and 5 minutes after successful intubation; grade of face mask ventilation; number of intubation attempts; intubation time; apnea duration; mucosal trauma; lip or dental injury; and presence of hypoxia, were all recorded.

MAIN RESULTS

The intubation attempts and perioperative safety data were comparable between the two groups. Intubation time and apnea duration were significantly shorter in the TL group than the GS group. All variables one minute after intubation were greater than baseline values except systolic blood pressure (SBP) in TL group. Both systolic blood pressure (SBP) and the degree of change of SBP from the baseline value one minute after intubation in TL group were significantly less than those of the GS group.

CONCLUSIONS

Trachlight offers a faster intubation and a milder hemodynamic response than GS.

The use of the GlideScope ® for tracheal intubation in patients with ankylosing spondylitis

BACKGROUND

The GlideScopeVideo Laryngoscope is a new intubating device. The aim of the study was to investigate the use of the GlideScopefor tracheal intubation in patients with ankylosing spondylitis (AS) undergoing general anaesthesia.

METHODS

Twenty AS patients were chosen to undergo tracheal intubation by the GlideScope. Preoperative airway assessments were carried out to predict the difficulty of tracheal intubation. Before intubation all patients were given a modified Cormack and Lehane (MCLS) grade and percentage of glottic opening (POGO) score by a separate anaesthetist using a Macintosh size 3 blade. The patients were then intubated, using the GlideScope, by a different anaesthetist during which the larynx was inspected and given another MCLS grade and POGO score.

RESULTS

Twelve of the AS patients were judged to have had difficult intubation by preoperative airway assessment. Eleven of the twelve patients had MCLS grades III or IV by direct laryngoscopy and were considered to have had a difficult laryngoscopy. Naso-tracheal intubations by the GlideScope were successful on 17/20 occasions, including 8 of the 11 difficult laryngoscopy. The GlideScope improved the MCLS grade and POGO score in the majority of AS patients compared with direct laryngoscopy (P<0.01).

CONCLUSIONS

The GlideScope provides a better laryngoscopic view than that of direct laryngoscopy. Most of the AS patients presenting with MCLS grade III or IV by direct laryngoscopy can be intubated successfully by the GlideScope. In elective patients with AS, awake fibreoptic intubation offers a higher level of security because it can be applied while maintaining spontaneous breathing. The use of GlideScope for tracheal intubation may be an alternative option in these patients who prefer their airway management under anaesthesia.

An evaluation of the GlideScope®, a new video laryngoscope for difficult airways

BACKGROUND AND OBJECTIVES

The GlideScope is a new video laryngoscope. The aim of our study was to assess its use compared to a Macintosh blade in airway scenarios on the Airman airway simulator. The scenarios were: 'normal' or resting state of the manikin, pharyngeal obstruction, cervical rigidity and tongue oedema.

METHODS

Thirty anaesthetists from the Christchurch Anaesthetic Department attempted to pass a bougie or stylet through the vocal cords of the manikin with a size 3 Macintosh blade, then the GlideScope. View at laryngoscopy, ease of 'intubation' and whether they thought the GlideScope would be useful in clinical practice were recorded.

RESULTS

Forty three percent (P = 0.02) found an improved view with the GlideScope in the pharyngeal obstruction scenario. In the other scenarios there was no significant difference in view. Reportage of ease of intubation showed no statistical difference in any scenarios. However, 93% of anaesthetists considered having the GlideScope would be useful if faced clinically with one or more of the studied scenarios.

CONCLUSIONS

The GlideScope improved the view in one of three difficult airway situations when used by anaesthetists with no formal training in its use. No single airway device offers a solution to all scenarios, however, we consider that the GlideScope is a useful addition to the range of difficult airway devices available.