Comparison of the C-MAC®and GlideScope®videolaryngoscopes in patients with cervical spine disorders and immobilisation

A prospective, pragmatic non-inferiority study of emergency intubation success with the single-use i-view versus standard reusable video laryngoscope

INTRODUCTION

Video laryngoscope (VL) technology improves first-pass success. The novel i-view VL device is inexpensive and disposable. We sought to determine the first-pass intubation success with the i-view VL device versus the standard reusable VL systems in routine use at each site.

METHODS

We performed a prospective, pragmatic study at two major emergency departments (EDs) when VL was used. We rotated i-view versus reusable VL as the preferred device of the month based on an a priori schedule. An investigator-initiated interim analysis was performed. Our primary outcome was a first-pass success with a non-inferiority margin of 10% based on the per-protocol analysis.

RESULTS

There were 93 intubations using the reusable VL devices and 81 intubations using the i-view. Our study was stopped early due to futility in reaching our predetermined non-inferiority margin. Operator and patient characteristics were similar between the two groups. The first-pass success rate for the i-view group was 69.1% compared to 84.3% for the reusable VL group. A non-inferiority analysis indicated that the difference (-15.1%) and corresponding 90% confidence limits (-25.3% to -5.0%) did not fall within the predetermined 10% non-inferiority margin.

CONCLUSIONS

The i-view device failed to meet our predetermined non-inferiority margin when compared to the reusable VL systems with the study stopping early due to futility. Significant crossover occurred at the discretion of the intubating operator during the i-view month.

A novel technique of handling the blade for videolaryngoscopy intubation in patients with a semi-rigid neck collar: a prospective randomized controlled trial

BACKGROUND

Semi-rigid neck collars to protect the cervical spine can limit the extent of neck movement and mouth opening; this may further complicate orotracheal intubation. We aimed to compare intubation environments obtained with videolaryngoscopy using the technique of gliding a blade under the epiglottis and that obtained using the conventional Macintosh blade technique of blade tip placement on the vallecula.

METHODS

This prospective randomized study included patients aged ≥ 20 years with American Society of Anesthesiologists physical status I-III scheduled for cervical spine surgery between October 2020 and August 2021. Patients were divided into two groups according to the placement of the blade of the McGrathTM videolaryngoscope: the gliding and conventional groups. The percentage of glottic opening (POGO) score was the primary endpoint. We also recorded the time to obtain the optimal laryngoscopic view, intubation duration, and ease and satisfaction of the researcher performing intubation.

RESULTS

Among 176 patients, the POGO scores were significantly higher in the gliding group than in the conventional group (88.9 ± 14.7 vs. 63.8 ± 27.4, P < 0.001). The time to achieve the optimal glottic view for intubation and duration of intubation were also shorter, and ease and satisfaction in performing intubation were better in the gliding group than in the conventional group.

CONCLUSION

Our findings demonstrated a superior glottic view and more favorable intubation environments when the blade tip was placed under the epiglottis than using the conventional Macintosh technique in patients with immobilized cervical spine.

Comparisons of Videolaryngoscopes for Intubation Undergoing General Anesthesia: Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background: The efficacy and safety of videolaryngoscopes (VLs) for tracheal intubation is still conflicting and changeable according to airway circumstances. This study aimed to compare the efficacy and safety of several VLs in patients undergoing general anesthesia. Methods: Medline, EMBASE, and the Cochrane Library were searched until 13 January 2020. The following VLs were evaluated compared to the Macintosh laryngoscope (MCL) by network meta-analysis for randomized controlled trials (RCTs): Airtraq, Airwayscope, C-MAC, C-MAC D-blade (CMD), GlideScope, King Vision, and McGrath. Outcome measures were the success and time (speed) of intubation, glottic view, and sore throat (safety). Results: A total of 9315 patients in 96 RCTs were included. The highest-ranked VLs for first-pass intubation success were CMD (90.6 % in all airway; 92.7% in difficult airway) and King Vision (92% in normal airway). In the rank analysis for secondary outcomes, the following VLs showed the highest efficacy or safety: Airtraq (safety), Airwayscope (speed and view), C-MAC (speed), CMD (safety), and McGrath (view). These VLs, except McGrath, were more effective or safer than MCL in moderate evidence level, whereas there was low certainty of evidence in the intercomparisons of VLs. Conclusions: CMD and King Vision could be relatively successful than MCL and other VLs for tracheal intubation under general anesthesia. The comparisons of intubation success between VLs and MCL showed moderate certainty of evidence level, whereas the intercomparisons of VLs showed low certainty evidence.

Video screen visualization patterns when using a video laryngoscope for tracheal intubation: A systematic review

OBJECTIVE

Published studies of video laryngoscopes are often limited by the lack of a clear definition of video laryngoscopy (VL). We performed a systematic review to determine how often published studies of VL report on video screen visualization.

METHODS

We searched PubMed, EMBASE and Scopus for interventional and observational studies in which a video laryngoscope equipped with a standard geometry blade was used for tracheal intubation. We excluded simulation based studies. Our primary outcome was data on video laryngoscope screen visualization. Secondary outcomes were explicit methodology for screen visualization.

RESULTS

We screened 4838 unique studies and included 207 (120 interventional and 87 observational). Only 21 studies (10% of 207) included any data on video screen visualization by the proceduralist, 19 in a yes/no fashion only (ie, screened viewed or not) and 2 with detail beyond whether the screen was viewed or not. In 11 more studies, visualization patterns could be inferred based on screen availability and in 16 more studies, the methods section stated how screen visualization was expected to be performed without reporting data collection on how the proceduralist interacted with the video screen. Risk of bias was high in the majority of included studies.

CONCLUSIONS

Published studies of VL, including many clinical trials, rarely include data on video screen visualization. Given the nuances of using a video laryngoscope, this is a critical deficiency, which largely prevents us from knowing the treatment effect of using a video laryngoscope in clinical practice. Future studies of VL must address this deficiency.

Perioperative management of spinal cord injury: the anesthesiologist's point of view

BACKGROUND

Traumatic spinal cord injury (SCI) is one of the most devastating events a person can experience. It may be life-threatening or result in long-term disability. This narrative review aims to delineate a systematic step-wise airways, breathing, circulation and disability (ABCD) approach to perioperative patient management during spinal cord surgery in order to fill some of the gaps in our current knowledge.

METHODS

We performed a comprehensive review of the literature regarding the perioperative management of traumatic spinal injuries from May 15, 2020, to December 13, 2020. We consulted the PubMed and Embase database libraries.

RESULTS

Videolaryngoscopy supplements the armamentarium available for airway management. Optical fiberscope use should be evaluated when intubating awake patients. Respiratory complications are frequent in the acute phase of traumatic spinal injury, with an estimated incidence of 36-83%. Early tracheostomy can be considered for expected difficult weaning from mechanical ventilation. Careful intraoperative management of administered fluids should be pursued to avoid complications from volume overload. Neuromonitoring requires investments in staff training and cooperation, but better outcomes have been obtained in centers where it is routinely applied. The prone position can cause rare but devastating complications, such as ischemic optic neuropathy; thus, the anesthetist should take the utmost care in positioning the patient.

CONCLUSIONS

A one-size fit all approach to spinal surgery patients is not applicable due to patient heterogeneity and the complexity of the procedures involved. The neurologic outcome of spinal surgery can be improved, and the incidence of complications reduced with better knowledge of patient-specific aspects and individualized perioperative management.

Comparing the first-attempt tracheal intubation success of the hyperangulated McGrath® X-blade vs the Macintosh-type CMAC videolaryngoscope in patients with cervical immobilization: a two-centre randomized controlled trial

We compared the hyperangulated McGrath X-blade with the Macintosh-type CMAC videolaryngoscope through the use of manual in-line stabilization on patients. The primary hypothesis was that the McGrath X-blade has a similar first-attempt success rate as the CMAC videolaryngoscope. 210 patients of ASA physical status I to III, aged 21 to 80 years old, undergoing general anesthesia requiring tracheal intubation were prospectively recruited into this two-centre randomized controlled trial, from June 2016 to April 2019. Patients with history of or predicted difficult airway, pre-existing dental risks, BMI > 35 kg/m², cervical spondylosis or myelopathy, aspiration risks, patients who declined to participate or lacked the mental capacity to give consent were excluded. Participants were intubated using either hyperangulated McGrath X-blade (MGX) or Macintosh-type CMAC (CM) videolaryngoscopy, with manual in-line stabilization. Primary outcome measured was first-attempt tracheal intubation success. Secondary outcomes included overall successful intubation within 2 attempts or 120 s, time to intubation, glottic view obtained and intubation-related complications. First-attempt success rates were 71.4% in the MGX group vs. 79.0% in the CM group (p = 0.26), with an absolute difference of -7.6% (95%CI -20%, 5.0%, p value = 0.26), but this trial was underpowered to detect a difference. Overall success was 91.4% (MGX) vs. 92.4% (CM) (p > 0.99). The Cormack & Lehane laryngeal grade was superior in the MGX group compared to CM group (Grade I: MGX 44%, CM 23%; Grade II: MGX 53%, CM 45%; Grade III: MGX 3%, CM 32%; p < 0.001). The median time to intubation using the MGX was longer than the CM [MGX 55.5 s (42.1-78.3), CM 43.8 s (38-55.3); p < 0.001]. Our study did not demonstrate a significant difference in efficacy between the McGrath X-blade and the CMAC videolaryngoscope. In patients with manual in-line stabilization, no anticipated airway difficulty and in the hands of experienced operators, the McGrath X-blade provided superior glottic views but conferred no advantage over the C-MAC, with a longer median time to intubation compared to the CMAC videolaryngoscope.Trial registration: Australian New Zealand Clinical Trial Registry (ACTRN12616000668404).

Effectiveness of intubation devices in patients with cervical spine immobilisation: a systematic review and network meta-analysis

BACKGROUND

Cervical spine immobilisation increases the difficulty of tracheal intubation. Many intubation devices have been evaluated in this setting, but their relative performance remains uncertain.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify randomised trials comparing two or more intubation devices in adults with cervical spine immobilisation. After critical appraisal, a random-effects network meta-analysis was used to pool and compare device performance. The primary outcome was the probability of first-attempt intubation success (first-pass success). For relative performance, the Macintosh direct laryngoscopy blade was chosen as the reference device.

RESULTS

We included 80 trials (8039 subjects) comparing 26 devices. Compared with the Macintosh, McGrath™ (odds ratio [OR]=11.5; 95% credible interval [CrI] 3.19-46.20), C-MAC D Blade™ (OR=7.44; 95% CrI, 1.06-52.50), Airtraq™ (OR=5.43; 95% CrI, 2.15-14.2), King Vision™ (OR=4.54; 95% CrI, 1.28-16.30), and C-MAC™ (OR=4.20; 95% CrI=1.28-15.10) had a greater probability of first-pass success. This was also true for the GlideScope™ when a tube guide was used (OR=3.54; 95% CrI, 1.05-12.50). Only the Airway Scope™ had a better probability of first-pass success compared with the Macintosh when manual-in-line stabilisation (MILS) was used as the immobilisation technique (OR=7.98; 95% CrI, 1.06-73.00).

CONCLUSIONS

For intubation performed with cervical immobilisation, seven devices had a better probability of first-pass success compared with the Macintosh. However, more studies using MILS (rather than a cervical collar or other alternative) are needed, which more accurately represent clinical practice.

CLINICAL TRIAL REGISTRATION

PROSPERO 2019 CRD42019158067 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=158067).

Comparison of Videolaryngoscope and Intubating Laryngeal Mask Airway for Tracheal Intubation with Manual-in-line Stabilization in Patients Undergoing Cervical Spine Surgery

Background:

This prospective, randomized study compared CMAC^® videolaryngoscope with intubating laryngeal mask airway (ILMA) for intubation under manual-in-line-stabilization (MILS) in patients undergoing cervical spine surgery. Settings and Design: Sixty-five ASA Physical Status Classes I and II patients aged 18–65 years undergoing elective cervical spine surgery were randomly allocated into two groups: group CM-intubation with CMAC^® videolaryngoscope (n = 33) and Group IL-intubation using ILMA (n = 32).

Materials and Methods:

Intubation was performed in all patients after the application of MILS. The primary outcomes included first attempt and overall intubation success rate, intubation time, and apnea time. The secondary objectives were degree of head movement, hemodynamic response, incidence of desaturation, sore throat, and tissue injury.

Statistical Analysis:

Normality of data was tested by the Kolmogorov–Smirnov test. Quantitative variables were compared using the unpaired t-test or Wilcoxon Mann–Whitney test and qualitative variables were compared using the Chi-square test/Fisher's exact test. P < 0.05 was considered statistically significant.

Results:

CM group had a higher first attempt (96.97%, P = 0.054) and overall (100%, P = 0.053) intubation success rate than IL group (81.25% and 87.5%, respectively). Group CM had a significantly shorter (P < 0.0001) intubation time (33.13 ± 11.82 s) than IL group (55.71 ± 19.28 s), but group CM had significantly longer (P < 0.0001) apnea time (33.13 ± 11.82 s) than IL group (22.03 ± 7.14 s). The incidence of head movement was significantly lower in IL group (P = 0.011). Hypoxemia did not occur. Postintubation hemodynamic changes and tissue injury were significantly higher in ILMA group.

Conclusion:

CMAC group had higher intubation success rate and significantly shorter intubation time. However, ILMA group had a significantly shorter apnea time and significantly lower incidence of head movements.

Difficult Intubation due to Penetrating Trauma from a Crossbow Bolt

We present the case of a patient with penetrating neck and craniofacial trauma from a self-inflicted crossbow bolt injury. This case highlights the challenges involved in prehospital airway management related to an in situ foreign object penetrating the oral cavity. We review the complications associated with such injuries and considerations for effective prehospital airway management.

GlideScope versus D-blade for tracheal intubation in cervical spine patients: A randomised controlled trial

Background and Aims

Airway management in patients with cervical spine pathology is challenging. The aim of the study was to evaluate GlideScope (GVL) and D blade of C-MAC (CMAC-D) using manual inline axial stabilisation (MIAS) for tracheal intubation in patients with cervical spine injury/pathology.

Methods

This is a randomised, single-blind, hospital-based study. After obtaining informed consent, 54 patients with cervical spine pathology/injury were grouped into GVL group or CMAC-D group, (n = 27 each) based on computer-generated random number table. Preoperative airway difficulty score (ADS) was calculated. The primary outcome of the study was intubation difficulty score (IDS) and the secondary outcomes included total time taken to secure airway, failure to intubate, haemodynamic parameters and adverse events. Data was represented in the form of number (%) or mean and standard deviation and median and interquartile range as appropriate. Chi square test was used for analysing IDS.

Results

The mean ± SD of IDS of the CMAC-D and GVL groups were 0.04 ± 0.2 (0.04-0.11) and 0.19 ± 0.40 (0.03-0.34), respectively, (P value = 0.096). The number (%) of patients with IDS > 0 was 1 (3.7) in CMAC-D and 5 (18.5) in GVL group, (P value = 0.192). Demographic data, ADS, Cormack-Lehane grading, success rate, time of tracheal intubation, type of surgeries, haemodynamic parameters and post-operative complications were similar in both the groups.

Conclusion

Both GVL and CMAC-D with MIAS are equally efficacious in tracheal intubation in cervical spine injury/pathology patients without other difficult airway management criteria.

Current evidence for the use of C-MAC videolaryngoscope in adult airway management: a review of the literature

The C-MAC videolaryngoscope is the first Macintosh-typed videolaryngoscope. Since the advent of its original version video Macintosh system in 1999, this device has been modified several times. A unique feature of C-MAC device is its ability to provide the 2 options of direct and video laryngoscopy with the same device. The available evidence shows that in patients with normal airways, C-MAC videolaryngoscope compared with direct laryngoscopy can provide comparable or better laryngeal views and exerts less force on maxillary incisors, but does not offer conclusive benefits with regard to intubation time, intubation success, number of intubation attempts, the use of adjuncts, and hemodynamic responses to intubation. In patients with predicted or known difficult airways, C-MAC videolaryngoscope can achieve a better laryngeal view, a higher intubation success rate and a shorter intubation time than direct laryngoscopy. Furthermore, the option to perform direct and video laryngoscopy with the same device makes C-MAC videolaryngoscope exceptionally useful for emergency intubation. In addition, the C-MAC videolaryngoscope is a very good tool for tracheal intubation teaching. However, tracheal intubation with C-MAC videolaryngoscope may occasionally fail and introduction of C-MAC videolaryngoscope in clinical practice must be accompanied by formal training programs in normal and difficult airway managements.

Use of the GlideScope Ranger Video Laryngoscope for Emergency Intubation in the Prehospital Setting: A Randomized Control Trial

OBJECTIVES

We sought to assess whether the GlideScope Ranger video laryngoscope may be a reliable alternative to direct laryngoscopy in the prehospital setting.

DESIGN

Multicenter, prospective, randomized, control trial with patient recruitment over 18 months.

SETTING

Four study centers operating physician-staffed rescue helicopters or ground units in Austria and Norway.

PATIENTS

Adult emergency patients requiring endotracheal intubation.

INTERVENTIONS

Airway management strictly following a prehospital algorithm. First and second intubation attempt employing GlideScope or direct laryngoscopy as randomized; third attempt crossover. After three failed intubation attempts, immediate use of an extraglottic airway device.

MEASUREMENTS AND MAIN RESULTS

A total of 326 patients were enrolled. Success rate with the GlideScope (n = 168) versus direct laryngoscopy (n = 158) group was 61.9% (104/168) versus 96.2% (152/158), respectively (p < 0.001). The main reasons for failed GlideScope intubation were failure to advance the tube into the larynx or trachea (26/168 vs 0/158; p < 0.001) and/or impaired sight due to blood or fluids (21/168 vs 3/158; p < 0.001). When GlideScope intubation failed, direct laryngoscopy was successful in 61 of 64 patients (95.3%), whereas GlideScope enabled intubation in four of six cases (66.7%) where direct laryngoscopy failed (p = 0.055). In addition, GlideScope was prone to impaired visualization of the monitor because of ambient light (29/168; 17.3%). There was no correlation between success rates and body mass index, age, indication for airway management, or experience of the physicians, respectively.

CONCLUSIONS

Video laryngoscopy is an established tool in difficult airway management, but our results shed light on the specific problems in the emergency medical service setting. Prehospital use of the GlideScope was associated with some major problems, thus resulting in a lower intubation success rate when compared with direct laryngoscopy.

Comparison of the ETView Single Lumen and Macintosh laryngoscopes for endotracheal intubation in an airway manikin with immobilized cervical spine by novice paramedics: A randomized crossover manikin trial

CONTEXT

Management of the airway of a trauma victim is considered challenging. Various approaches have been described to achieve airway control in this setup; many of them include video-assited viewing of the larynx during intubation. ETView Single Lumen (SL) is a novice single-use endotracheal tube equiped with a video camera and a light source at its distal tip. Its use was previously described in seeral clinical and training setups.

OBJECTIVE

The aim was to evaluate the efficacy of the VivaSight SL compared with classic direct laryngoscopy performed with a Macintosh blade in a manikin-simulated trauma setup presenting various degrees of airway challenge when performed by inexperienced physicians.

DESIGN, SETTING, PARTICIPANTS

This was prospective, randomized, crossover, manikin trial. After short training on the ETView system, 67 novice paramedics attempted to perform oral intubation using both standard direct laryngoscopy (MAC group) and the VivaSight SL endotracheal tube (ETView group) in a randomized order on manikins in 3 increasingly more difficult scenarios (simple intubation, cervical spine manual stabilization, and with cervical collar in place).

OUTCOME MEASURE

Overall success rate, time to intubation, number of intubation attempts, laryngeal view grade, dental compression, and overall participant satisfaction were monitored.

RESULTS

Duration of intubation and number of attempts were significantly superior in the ETView group in the latter 2 more challenging scenarios. All other parameters showed superiority to the ETView group in all 3 scenarios.

CONCLUSION

The VivaSight SL system performed better in a complex scenario of airway management of a trauma victim in need for cervical spine stabilization performed by novice caregivers compared to standard direct laryngoscopy and should be considered in this clinical setup.

A comparison of videolaryngoscopes for tracheal intubation in predicted difficult airway: a feasibility study

Background

Videolaryngoscopy has become increasingly attractive for the routine management of the difficult airway. Glidescope® is well studied in the literature while imago V-Blade® is a recent videolaryngoscope. This is a feasibility study with 1:1 case-control sequential allocation comparing Imago V-Blade ® and Glidescope® in predicted difficult airway settings.

Methods

Two senior anesthesiologists with no clinical experience in video assisted intubation but previously trained in a simulated scenario, performed the endotracheal intubations with Imago V-Blade® and Glidescope®. A third experienced anesthesiologist supervised the procedures. Forty-two patients, 21 for each group, with the presence of predicted difficult airway according to the Italian guideline were included. The primary end point is the feasibility of intubation. The secondary end-points are the success to intubate in the first attempt, the intubation time, the Cormack and Lehane score view, the comparison of the intubation difficulty scale (IDS) score and the need for maneuvers to aid the endotracheal intubation comparing Imago V-Blade® and Glidescope®.

Results

The intubation was achieved in 100% of cases in both groups. No differences were found in the first-attempt success rate (p = 0.383), intubation time (p = 0.280), Cormack and Lehane score view (p = 0.799) and IDS score (p = 0.252). Statistical differences were found in external laryngeal pressure (p = 0.005), advancement of the blade (p = 0.024) and use of increasing lifting force (p = 0.048).

Conclusions

This feasibility study showed that the intubation with the newly introduced Imago V-Blade® is feasible. Further randomized and/or non-inferiority trials are needed to evaluate the benefit of Imago V-Blade® in this procedure.

Trial registration

Clinicaltrials.gov NCT02897518. Retrospectively registered 25 August 2016

A comparison of McGrath MAC® and standard direct laryngoscopy in simulated immobilized cervical spine pediatric intubation: a manikin study

Emergency airway management in children is generally considered to be challenging, and endotracheal intubation requires a high level of personal skills and experience. Immobilization of the cervical spine is indicated in all patients with the risk of any cervical spine injury but significantly aggravates endotracheal intubation. The best airway device in this setting has not been established yet, although the use of videolaryngoscopes is generally promising. Seventy-five moderately experienced paramedics of the Emergency Medical Service of Poland performed endotracheal intubations in a pediatric manikin in three airway scenarios: (A) normal airway, (B) manual in-line cervical immobilization, and (C) cervical immobilization using a Patriot cervical extrication collar and using two airway techniques: (1) McGrath videolaryngoscope and (2) Macintosh blade in a randomized sequence. First-attempt intubation success rate, time to intubation, glottis visualization, and subjective ease of intubation were investigated in this study. Intubation of difficult airways, including manual in-line and cervical collar immobilization, using the McGrath was significantly faster, with a higher first-attempt intubation success rate, better glottic visualization, and ease of intubation, compared to Macintosh-guided intubation. In the normal airway, both airway techniques performed equal.

CONCLUSION

Our manikin study indicates that the McGrath may be a reasonable first intubation technique option for endotracheal intubation in difficult pediatric emergencies. Further clinical studies are therefore indicated. What is known : • Airway management in pediatrics is challenging and requires a high level of skills and experience. Cervical immobilization is indicated in all patients with any risk of cervical spine injury, but it significantly aggravates endotracheal intubation in these patients. Videolaryngoscopes have been reported to ease intubation and provide better airway visualization in the regular clinical setting. What is new: • The McGrath is an easy-to-use and clinically often used videolaryngoscope, but it has never been investigated in pediatrics with an immobilized cervical spine. In the normal airway, the McGrath provided better airway visualization compared to Macintosh laryngoscopy. However, better visualization did not lead to decreased time to intubation and a higher success rate of the first intubation attempt. In difficult airways, the McGrath provided better airway visualization and this led to faster intubation, a higher first-attempt intubation success rate, and better ease of intubation compared to Macintosh-guided intubation.

Clinical evaluation and airway management for adults with cervical spine instability

Airway management of patients with cervical spine instability may be difficult as a result of immobilization, and may be associated with secondary neurologic injury related to cervical spine motion. Spinal cord instability is most common in patients with trauma, but there are additional congenital and acquired conditions that predispose to subacute cervical spine instability. Patients with suspected instability should receive immobilization during airway management with manual in-line stabilization. The best strategy for airway management is one that applies the technique with the highest likelihood of success on the first attempt and the lowest biomechanical influence on a potentially unstable spine.