A Comparison of the GlideScope® with the Macintosh Laryngoscope for Tracheal Intubation in Patients with Simulated Difficult Airway

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.

Pediatric airway management: comparing the Berci-Kaplan Video Laryngoscope with direct laryngoscopy

OBJECTIVES

To assess the utility of the Berci-Kaplan Video Laryngoscope (VL) in pediatric anesthesia.

BACKGROUND

The VL is designed to improve visualization of the glottis during tracheal intubation of normal and difficult airways in adults. This study was designed to assess the visual quality and the ease of tracheal intubation in children using the VL when compared with direct laryngoscopy (DL).

METHODS

Sixty children, aged 2-16 years requiring tracheal intubation, were enrolled in this prospective, randomized clinical trial. Following induction of anesthesia and muscle paralysis, the first laryngoscopy method, using either a DL or the VL, was performed by one anesthetist, and the laryngoscopic view was graded according to the Cormack-Lehane scale. Laryngoscopy and grading of the view in the second method were then performed by a second anesthetist. Tracheal intubation was completed following the second laryngoscopy, and time to intubation was recorded.

RESULTS

The average age and weight were 8.9 +/- 3.6 years and 34.9 +/- 16.0 kg respectively. Videolaryngoscopy improved 8/11 grade 2 views to grade 1 (P = 0.02), and one grade 3 to a grade 2. Three grade 2 views remained unchanged from DL to VL. 4/30 VL intubations required two attempts, and 1/30 failed after two attempts, but was easily intubated with DL. Median time (range) was 16.0 s (14.0-20.0 s) and 22.5 s (17.8-35.0 s) for DL and VL respectively (P < 0.001).

CONCLUSION

Videolaryngoscopy provides better views than DL at the expense of time to intubate. Although the time taken to intubate is increased with the VL, it is clinically acceptable.

Advanced airway management

PURPOSE OF REVIEW

Advanced airway management in children can be challenging, and the potential for morbidity following failed attempts is high.

RECENT FINDINGS

Supraglottic rescue devices, including the laryngeal mask airway, esophageal-tracheal combination tube, and laryngeal tube have been shown to be suitable ventilation strategies following failed intubation and in arrest scenarios. In addition, a newly developed reversal agent for rocuronium is being investigated as a means of limiting the duration of neuromuscular blockade following rapid sequence induction. Finally, the advent of video laryngoscopy has been shown to have advantages over traditional direct laryngoscopy, in terms of both patient care and training.

SUMMARY

Pediatric providers are encouraged to develop familiarity with emerging rescue ventilation devices, as well as recent advances in the practice of rapid sequence induction and laryngoscopy.

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.

Faster intubation with direct laryngoscopy vs handheld videoscope in uncomplicated manikin airways

OBJECTIVE

To compare average time to successful intubation and success rates using direct laryngoscopy (DL) with those using a battery-operated videoscope (VS) in uncomplicated manikin intubations.

METHODS

Forty-four paramedics and emergency medicine faculty and residents received training with DL and VS. Participants performed 3 timed trials using each device. A single group repeated-measures analysis of variance for average time measurements was performed.

RESULTS

Grouping physicians and paramedics, mean time to successful intubation for DL was 14.6 seconds (SD, 4.3 seconds) and for VS was 25.9 seconds (SD, 9.2 seconds; P < .001). All attempts were successful with both devices. A secondary measure compared intubation times for physicians and paramedics on both devices. For DL, mean time to successful intubation for physicians was 13.2 seconds (SD, 3.8 seconds) and for paramedics, 15.9 seconds (SD, 4.3 seconds; P > .43). For VS, mean time for physicians was 26.0 seconds (SD, 10.0 seconds) and for paramedics, 25.7 seconds (SD, 8.6 seconds; P > .43).

CONCLUSIONS

Intubation with DL in uncomplicated manikin airways was faster than with VS (P < .001). Success rates were equal.

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

BACKGROUND

Paramedics 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.

METHODS

We 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.

RESULTS

The 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.

CONCLUSION

The 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.

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.

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.

Comparison of the single use and reusable intubating laryngeal mask airway

We compared the times to intubate the trachea using the single use (Group S) and reusable (Group C) intubating laryngeal mask (ILMA(TM)), in 84 healthy patients with normal airways undergoing elective gynaecological surgery. There was no significant difference in the ease of insertion of the ILMA or the tracheal tube, or time to successful insertion (Group S, 101.4 s (SD 63.2) vs Group C, 90.4 s (SD 46.1), p = 0.366). The ILMA was successfully inserted on first attempt in 63% of Group S patients and in 68% of Group C patients. After one or two attempts the overall success rate for both groups was 93%. There was a failure to insert the ILMA in two patients in each group. There was no difference in side-effects (desaturation S(p)o(2) < 95%, bleeding, oesophageal intubation, lip, dental or mucosal injury, or sore throat postoperatively). We conclude that the disposable ILMA is an acceptable alternative to the reusable ILMA.

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.

Complications associated with the use of the GlideScope videolaryngoscope

PURPOSE

Two cases are presented wherein the GlideScope videolaryngoscope (GVL) facilitated laryngeal exposure and successful endotracheal intubation, but resulted in pharyngeal injury.

CLINICAL FEATURES

GlideScope videolaryngoscopy was performed in two female patients, whose airways were anticipated to present difficulties for direct laryngoscopy. In the first case, following induction of anesthesia, moderate difficulty was encountered in directing the endotracheal tube (ETT) into the patient's larynx. In the second case, minimal difficulty with the GVL was experienced, and no problems were identified with airway instrumentation until the drapes covering the patient's face were removed. In both instances, the ETT had passed through the right palatopharyngeal arch, requiring suturing in the first patient, and electrocautery in the second patient.

CONCLUSION

There have been no previously published reports of injuries related to GlideScope laryngoscopy, but perforation of the palatopharyngeal arch occurring in two patients demonstrates a rare but potentially important complication of the GVL. Strategies to minimize this complication are considered.

Comparison of the GlideScope video laryngoscope vs. the intubating laryngeal mask for females with normal airways

BACKGROUND AND OBJECTIVE

In this randomized clinical study, we compared the intubation success rates of the intubating laryngeal mask airway with the GlideScope in patients with normal airways. The primary hypothesis was that the intubating laryngeal mask airway was equally effective as the GlideScope in terms of successful intubation times.

METHODS

Sixty ASA I and II adult patients undergoing elective gynaecological surgery were randomly allocated into either the intubating laryngeal mask airway group or the GlideScope group. After a standard anaesthetic intravenous induction, orotracheal intubation was performed. Time taken for successful tracheal intubation, ease of device insertion, difficulty of tracheal intubation, manoeuvres needed to aid tracheal intubation, number of intubation attempts, haemodynamic changes every 2.5 min interval for 5 min and complications during tracheal intubation were recorded.

RESULTS

Time to successful intubation was longer (mean 68.4 s +/- 23.5 vs. 35.7 s +/- 10.7; P < 0.05), mean difficulty score was higher (mean 16.7 +/- 16.3 vs. 7.3 +/- 13.1; P < 0.05) and more intubation attempts were required in the intubating laryngeal mask airway group.

CONCLUSION

The GlideScope improved intubation time and difficulty score for tracheal intubation when compared with the intubating laryngeal mask airway in our patients. Blind intubation through the intubating laryngeal mask airway offers no advantages over the GlideScope in patients with normal airways. Despite its limitations, the intubating laryngeal mask airway is a valuable adjunct, especially in cases of difficult airway management when it can provide ventilation in between intubation attempts.