Comparison of intubation success and glottic visualization using King Vision and C-MAC videolaryngoscopes in patients with cervical spine injuries with cervical immobilization: A randomized clinical trial

Comparison of C-MAC ® conventional blade, D-Blade ™ , and Macintosh laryngoscopes for endotracheal intubation in patients with simulated immobilization using manual in-line stabilization: A randomized trial

BACKGROUND

A difficult airway is anticipated with cervical spine injuries (CSIs) as immobilization techniques such as manual in-line stabilization (MILS) are used, which distort the oro-pharyngeal-laryngeal axis. Video laryngoscopes (VLs) make difficult airway management easy, as they do not require axis alignment. The present study aimed to compare the total time taken by Macintosh laryngoscope (ML), conventional blade, and D-blade ™ of C-MAC ® VL in simulated CSI scenarios using MILS.

METHODS

Ninety patients were randomly allocated into three groups: Group M (ML), Group C (conventional blade of C-MAC ® ), and Group D (D-blade ™ of C-MAC ® ) with MILS applied before intubation. Primary outcome was the total time taken for successful intubation, while secondary outcomes were to assess Cormack-Lehane (CL) grade, number of attempts, hemodynamic response, and associated complications.

RESULTS

Total time for intubation in Group C was 23.40 ± 7.06 sec compared to 35.27 ± 6.53 and 47.27 ± 2.53 sec in groups D and M, respectively ( P < 0.001). CL-grade I was observed in 15/30 (50%) in Group M, 25/30 (83.3%) in Group C, and 29/30 (96.7%) in Group D. Group M reported 7/30 (23.3%) failed intubations, while none were observed in other groups. Hemodynamic parameters were significantly higher at 3 and 5 min in Group M. Postoperative sore throat was recorded in 12/30 (40%) in Group M compared to 3/30 (10%) in groups C and D each ( P value 0.037).

CONCLUSION

C-MAC ® VL requires less time for intubation, provides better glottic view, and has higher success, with better attenuation of hemodynamic response and fewer complications compared to ML.

Clinically Preferred Videolaryngoscopes in Airway Management: An Updated Systematic Review

Videolaryngoscopes (VLs) have emerged as a safety net offering several advantages over direct laryngoscopy (DL). The aim of this study is to expand on our previous study conducted in 2016, to deduce which VL is most preferred by clinicians and to highlight any changes that may have occurred over the past 7 years. An extensive systematic literature review was performed on Medline, Embase, Web of Science, and Cochrane Central Database of Controlled Studies for articles published between September 2016 and January 2023. This review highlighted similar results to our study in 2016, with the CMAC being the most preferred for non-channelled laryngoscopes, closely followed by the GlideScope. For channelled videolaryngoscopes, the Pentax AWS was the most clinically preferred. This review also highlighted that there are minimal studies that compare the most-used VLs, and thus we suggest that future studies directly compare the most-used and -preferred VLs as well as the specific nature of blades to attain more useful results.

Comparison of Tracheal Intubation Using King Vision (Non-channeled Blade) and Tuoren Video Laryngoscopes in Patients With Cervical Spine Immobilization by Manual In-Line Stabilization: A Randomized Clinical Trial

BACKGROUND

Glottic visualization on cervical immobilization with manual in-line stabilization (MILS) might be challenging in individuals with cervical spine injuries. We compared non-channeled King Vision video laryngoscope (VL) (Ambu GmbH, Bad Nauheim, Germany) with Tuoren video laryngoscope (Henan Tuoren Medical Device, Zhengzhou, China) for endotracheal intubation in patients with cervical spine immobilization.

METHODS

A total of 124 patients undergoing elective surgery under general anesthesia were included in this study. After induction of general anesthesia, patients were randomized into two groups (62 each): group K (non-channeled blade of King Vision video laryngoscope) and group T (Tuoren video laryngoscope). Cervical spine immobilization was achieved with manual in-line stabilization. The success of the first pass intubation, the time required to intubate, glottic visualization, and intubation difficulty score (IDS) were recorded.

RESULTS

The first-attempt success rate of intubation was 95.2% (59 out of 62 patients) in group K and 90.3% (56 out of 62 patients) in group T, which were comparable. The mean glottic visualization time was significantly less with group T (12.74 ± 6.32 seconds) compared to group K (17.92 ± 4.24 seconds). Intubation time was significantly faster with group K (18.79 ± 5.857 seconds) compared to group T (27.21 ± 8.514 seconds). Both video laryngoscopes provided good grades of glottic visualization.

CONCLUSIONS

 We conclude that the performance of the Tuoren video laryngoscope is similar to the King Vision video laryngoscope in terms of first-attempt intubation success rate and glottic visualization score in patients with cervical spine immobilization by manual in-line stabilization. Although glottic visualization time was shorter with Tuoren VL, we could achieve faster intubation with King Vision VL.

Partial vs full glottic view with CMACTM D blade intubation of airway with simulated cervical spine injury: a randomized controlled trial

PURPOSE

A previous study reported a shorter time to tracheal intubation by reducing percentage of glottic opening (POGO) view to <50% when intubating a normal adult airway using the Glidescope^TM blade. We evaluate the efficacy of reducing POGO to <50% when intubating patients with rigid cervical immobilization using CMAC^TM D blade.

METHODS

One hundred and four adult patients were randomized to group POGO 100% or POGO <50% . Laryngoscopy was performed by advancing tip of the D blade at vallecula. POGO 100% was achieved by exerting upward force to displace epiglottis until glottic opening from the anterior commissure to inter arytenoid notch. POGO < 50% was acquired by withdrawing the D blade tip dorsally from vallecula. The primary outcome was time to intubation.

RESULTS

The median time (IQR) to successful intubation was 29 (25-35) seconds for group POGO < 50% and 34 (28-40) seconds for group with POGO 100% (difference in medians, 5 seconds; 95% confidence interval, 2 to 8, p = 0.003). Complications were minor.

CONCLUSION

Using the CMAC^TM D blade with a reduced POGO in patients with cervical spine immobilization resulted in faster tracheal intubation.

TRIAL REGISTRATION

The trial is registered at ClinicalTrial.gov (CT.gov identifier: NCT04833166).

The Use of the Shikani Video-Assisted Intubating Stylet Technique in Patients with Restricted Neck Mobility

Among all the proposed predictors of difficult intubation defined by the intubation difficulty scale, head and neck movement (motility) stands out and plays as a crucial factor in determining the success rate and the degree of ease on endotracheal intubation. Aside from other airway tools (e.g., supraglottic airway devices), optical devices have been developed and applied for more than two decades and have shown their superiority to conventional direct laryngoscopes in many clinical scenarios and settings. Although awake/asleep flexible fiberoptic bronchoscopy is still the gold standard in patients with unstable cervical spines immobilized with a rigid cervical collar or a halo neck brace, videolaryngoscopy has been repeatedly demonstrated to be advantageous. In this brief report, for the first time, we present our clinical experience on the routine use of the Shikani video-assisted intubating stylet technique in patients with traumatic cervical spine injuries immobilized with a cervical stabilizer and in a patient with a stereotactic headframe for neurosurgery. Some trouble-shooting strategies for this technique are discussed. This paper demonstrates that the video-assisted intubating stylet technique is an acceptable alternative airway management method in patients with restricted or confined neck motility.

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.

2022 American Society of Anesthesiologists Practice Guidelines for Management of the Difficult Airway

The American Society of Anesthesiologists; All India Difficult Airway Association; European Airway Management Society; European Society of Anaesthesiology and Intensive Care; Italian Society of Anesthesiology, Analgesia, Resuscitation and Intensive Care; Learning, Teaching and Investigation Difficult Airway Group; Society for Airway Management; Society for Ambulatory Anesthesia; Society for Head and Neck Anesthesia; Society for Pediatric Anesthesia; Society of Critical Care Anesthesiologists; and the Trauma Anesthesiology Society present an updated report of the Practice Guidelines for Management of the Difficult Airway.

Tracheal intubation with King Vision video laryngoscope in patients with cervical spine instability-Comparison of straight versus curved reinforced endotracheal tubes

Background and Aims:

King Vision video laryngoscope is commonly used to facilitate intubation in corrective surgery for cervical spine instability patients due to less manipulation. Curved and straight reinforced tracheal tubes are regularly used in this surgery as neck of the patient is likely to be flexed. We aimed to compare intubation characteristics between the curved and straight reinforced tubes through King Vision video laryngoscope in patients to be operated for cervical spine instability with the primary objective being intubation time.

Methods:

Sixty patients undergoing cervical spine surgery were enroled in this prospective randomised comparative clinical study. All were intubated after applying manual in-line stabilisation of the neck, using either curved (group C) or straight (group S) reinforced endotracheal tubes through King Vision video laryngoscope. The intubation time, number of attempts, incidence of tube impingement with arytenoids/aryepiglottic folds, optimisation manoeuvres required and complications were observed. Unpaired ‘t’ test and Chi-square test were used to analyse the data using MedCalc software, version 12.5.

Results:

Time taken for intubation was shorter with curved compared to straight reinforced tube (16.24 ± 3.09 vs. 29.08 ± 5.48 seconds, P < 0.0001) The first attempt success rate was higher using curved than straight reinforced tube (93.3% vs. 70%, P = 0.02). Incidences of impingement with arytenoids/ aryepiglottic folds and optimisation manoeuvres required more with the straight reinforced tube.

Conclusion:

The intubation was fast and with higher first attempt success rate with curved than with straight reinforced tube through King Vision videolaryngoscope when used in patients with cervical spine instability.

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.

Tracheal intubation in patients at risk for cervical spinal cord injury: A systematic review

BACKGROUND

Tracheal intubation in patients at risk for secondary spinal cord injury is potentially difficult and risky.

OBJECTIVES

To compare tracheal intubation techniques in adult patients at risk for secondary cervical spinal cord injury undergoing surgery. Primary outcome was first-attempt failure rate. Secondary outcomes were time to successful intubation and procedure complications.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs) with trial sequential analysis (TSA).

DATA SOURCES

Databases searched up to July 2019.

ELIGIBILITY

Randomized controlled trials comparing different intubation techniques.

RESULTS

We included 18 trials enrolling 1972 patients. Four studies used the "awake" approach, but no study compared awake versus non-awake techniques. In remaining 14 RCTs, intubation was performed under general anesthesia. First-attempt failure rate was similar when comparing direct laryngoscopy or fiberoptic bronchoscopy versus other techniques. A better first-attempt failure rate was found with videolaryngoscopy and when pooling all the fiberoptic techniques together. All these results appeared not significant at TSA, suggesting inconclusive evidence. Intubating lighted stylet allowed faster intubation. Postoperative neurological complications were 0.34% (no significant difference among techniques). No life-threatening adverse event was reported; mild local complications were common (19.5%). The certainty of evidence was low to very low mainly due to high imprecision and indirectness.

CONCLUSIONS

Videolaryngoscopy and fiberoptic-assisted techniques might be associated with higher first-attempt failure rate over controls. However, low to very low certainty of evidence does not allow firm conclusions on the best tracheal intubation in patients at risk for cervical spinal cord injury.

Video Laryngoscopic Intubation Using the King VisionTM Laryngoscope in a Simulated Cervical Spine Trauma: A Comparison Between Non-Channeled and Channeled Disposable Blades

Videolaryngoscopes may reduce cervical spine movement during tracheal intubation in patients with neck trauma. This manikin study aimed to compare the performance of disposable non-channeled and channeled blades of the King Vision™ videolaryngoscope in simulated cervical spine injury. Fifty-eight anesthesiologists in training intubated the TruMan manikin with the neck immobilized using each blade in a randomized order. The primary outcome was the time needed for tracheal intubation, secondary aims included total success rate, the time required for visualization of the larynx, number of attempts, view of the vocal cords, and subjective assessment of both methods. Intubation time with the channeled blade was shorter, with a median time of 13 s (IQR 9-19) vs. 23 s (14.5-37.5), p < 0.001, while times to visualization of the larynx were similar in both groups (p = 0.54). Success rates were similar in both groups, but intubation with the non-channeled blade required more attempts (1.52 vs. 1.05; p < 0.001). The participants scored the intubation features of the channeled blade significantly higher, while visualization features were scored similarly in both groups. Both blades of the King Vision™ videolaryngoscope are reliable intubation devices in a simulated cervical spine injury in a manikin model when inserted by non-experienced operators. The channeled blade allowed faster intubation of the trachea.

Video Versus Direct Laryngoscopy for Inpatient Emergency Intubation in Adults

BACKGROUND

Emergency intubation carries a higher risk of complications than elective airway management. Video laryngoscopy (VL) could potentially improve patient safety. The goal of this study was to determine whether VL is superior to direct laryngoscopy for the emergency intubation of adults in the inpatient setting.

METHODS

Pertinent studies were retrieved by a systematic literature search in the MEDLINE, Embase, and CENTRAL databases. The selection of studies, data extraction, and assessment of the potential for bias were carried out independently by two of the authors. Effect sizes were reported as odds ratios (OR) or mean differences (MD). The primary endpoint was successful intubation at the first attempt. Further variables were considered as secondary endpoints.

RESULTS

1098 titles and abstracts were retrieved, and the full texts of 43 articles were examined. Eight randomized and controlled trials, with a total of 1796 patients, were analyzed. VL was not found to confer any statistically significant advantage with respect to successful intubation at the first attempt (OR 0.72, 95% confidence interval [0.47; 1.12]) or with respect to the time to successful intubation (MD -8.99 seconds [-24.00; 6.01]). On the other hand, the use of VL was significantly associated with a lower number of intubation attempts (MD -0.17 [-0.31; -0.03]) and with a lower frequency of esophageal intubation (OR 0.27 [0.10; 0.75]).

CONCLUSION

The routine use of VL for airway management in emergency medicine might improve patient safety, as VL is associated with a lower number of intubation attempts and with a lower frequency of esophageal intubation. Further randomized controlled trials are needed before any definitive conclusions can be drawn about the advantages of video laryngoscopy.

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.