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

Airway management in patients with suspected or confirmed cervical spine injury: Guidelines from the Difficult Airway Society (DAS), Association of Anaesthetists (AoA), British Society of Orthopaedic Anaesthetists (BSOA), Intensive Care Society (ICS), Neuro Anaesthesia and Critical Care Society (NACCS), Faculty of Prehospital Care and Royal College of Emergency Medicine (RCEM)

BACKGROUND

There are concerns that airway management in patients with suspected or confirmed cervical spine injury may exacerbate an existing neurological deficit, cause a new spinal cord injury or be hazardous due to precautions to avoid neurological injury. However, there are no evidence-based guidelines for practicing clinicians to support safe and effective airway management in this setting.

METHODS

An expert multidisciplinary, multi-society working party conducted a systematic review of contemporary literature (January 2012-June 2022), followed by a three-round Delphi process to produce guidelines to improve airway management for patients with suspected or confirmed cervical spine injury.

RESULTS

We included 67 articles in the systematic review, and successfully agreed 23 recommendations. Evidence supporting recommendations was generally modest, and only one moderate and two strong recommendations were made. Overall, recommendations highlight key principles and techniques for pre-oxygenation and facemask ventilation; supraglottic airway device use; tracheal intubation; adjuncts during tracheal intubation; cricoid force and external laryngeal manipulation; emergency front-of-neck airway access; awake tracheal intubation; and cervical spine immobilisation. We also signpost to recommendations on pre-hospital care, military settings and principles in human factors.

CONCLUSIONS

It is hoped that the pragmatic approach to airway management made within these guidelines will improve the safety and efficacy of airway management in adult patients with suspected or confirmed cervical spine injury.

Structured Routine Use of Styletubation for Oro-Tracheal Intubation in Obese Patients Undergoing Bariatric Surgeries-A Case Series Report

The aim of this case series report is to provide a new topical view of styletubation (video intubating stylet technique) in obese patients undergoing bariatric surgeries. In contrast to various conventional direct laryngoscopes (DLs), videolaryngoscopes (VLs) have been applied in such obese populations with potentially difficult airway complications. The safety and effectiveness of VLs have been repeatedly studied, and the superiority of VLs has then been observed in and advocated for routine use. In this article, among our vast use experiences with styletubation (more than 54,998 patients since 2016) for first-line routine tracheal intubation, we present the unique experience to apply the styletubation technique in obese patients undergoing bariatric surgery. Consistent with the experiences applied in other patient populations, we found the styletubation technique itself to be swift (the time to intubate from 5 s to 24 s), smooth (first-attempt success rate: 100%), safe (no airway complications), and easy (high subjective satisfaction). The learning curve is steep, but competency can be enhanced if technical pitfalls can be avoided. We, therefore, propose that the styletubation technique can be feasibly and routinely applied as a first-line airway modality in obese patients undergoing bariatric surgery.

Impact of airway devices and emergency airway techniques characteristics on airway adverse events in mainland China: a cross-sectional study

BACKGROUND

Novel airway devices are becoming widely available, yet it is unclear whether the techniques or preferences of airway practitioners for airway management have been impacted. Given these facts, a cross-sectional study of the current status of airway management in mainland China was conducted and compared with previous survey findings.

METHODS

The national survey was conducted from November 7th to November 28th, 2022. An electronic survey was sent to the New Youth Anesthesia Forum to examine the availability of airway devices, preference for front-of-neck access (FONA) techniques, the incidence of adverse airway events, and the status of airway management training.

RESULTS

Questionnaires were completed by 3783 respondents, with a response rate of 72.14%. So far, the availability of optical airway devices has improved dramatically, with the availability of videolaryngoscopes reaching 97.18%. When encountering "cannot intubate, cannot ventilate" (CICV) scenarios, the majority of respondents would prefer needle cricothyrotomy to establish FONA. However, less than a quarter of respondents had actually performed it. Moreover, the incidence of airway adverse events from 2016 to 2022 was 11.48%, of which 5.13% were brain damage or death. Multivariate logistic regression analysis revealed that the ability to perform FONA techniques (odds ratio [OR] 0.23, 95% CI: 0.16, 0.32; P<0.001) and the availability of difficult airway management carts or kits (OR 0.59, 95% CI 0.41, 0.85; P=0.005) were associated with a lower incidence of airway adverse events.

CONCLUSIONS

Optical airway devices can overcome some of the challenges posed by difficult airways, yet the CICV scenario remains a major obstacle. The future focus of airway management should be training, particularly for complicated emergency airway techniques.

Comparison of Efficacy of Intubation with HugeMed Non-channelled Video Laryngoscope, McCoy and Macintosh Laryngoscope in Simulated Difficult Laryngoscopy Using Rigid Cervical Collar: A Prospective Randomized Trial

BACKGROUND AND AIMS

In cervical spine injuries, there is an impairment in positioning of the patient to maintain the airway axis during endotracheal intubation (ETI). Literature shows video laryngoscope (VLS) facilitating the intubation in these patients with cervical immobilization. VL3 VLS (HugeMed Medical Technical Development, Shenzhen, China) is a newer VLS with limited studies. The primary aim of this study is to compare the efficacy of ETI using VL3 VLS with Macintosh and McCoy (MC) blades for simulated difficult airway with rigid cervical collar (RCC). The secondary aim was to compare the oral insertion of laryngoscope and intraoral bleeding.

METHODS

One hundred and fifty patients were randomly divided into three groups depending on laryngoscope used for ETI. Group M, Group V, and Group MC used Macintosh, VL3, and MC laryngoscopic blades, respectively, for ETI. During ETI, the Intubation Difficulty Scale (IDS), intubation time (IT), ease of laryngoscope insertion, and any bleeding intraorally were noted. The data collected were further analyzed.

RESULTS

IDS was statistically significantly least (0.9 ± 1.5) with VL3 VLS compared to direct laryngoscopy with Macintosh and MC blades. There was significantly no difference in IT among the three groups. Insertion of blade of VL3 was significantly more difficult than Macintosh or MC. Intraoral bleeding was present in 8% of patients with VL3.

CONCLUSION

VL3 VLS can be used for ETI during cervical immobilization using RCC. More studies are needed to define its efficacy in different difficult airway situations compared with different VLS.

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.

[Airwaymangement in Emergencies]

Emergency airway management is a rare but essential emergency medical intervention directly impacting morbidity and mortality of emergency patients. The success of airway management depends on various factors such as patient anatomy, environmental aspects and the provider performing the procedure. Therefore, the use of a clearly structured algorithm for anticipating the difficult airway in emergency situations is strongly recommended. Our article explains different ways of securing the airway as part of a structured algorithm as well as pitfalls and helpful tips.

Indirect laryngoscopy is more effective than direct laryngoscopy when tracheal intubation is performed by novice operators: a systematic review, meta-analysis, and trial sequential analysis

PURPOSE

We sought to perform a systematic review and meta-analysis to determine whether indirect laryngoscopy has an advantage over direct laryngoscopy in terms of the tracheal intubation rate, glottic visualization, and intubation time when used by novice operators.

METHODS

We extracted adult prospective randomized trials comparing tracheal intubation with indirect vs direct laryngoscopy in novice operators from electronic databases. We extracted the following data from the identified studies: success rate, glottic visualization, and intubation time. Data from each trial were combined via a random-effects model to calculate the pooled relative risk (RR) or weighted mean difference (WMD) with a 95% confidence interval (CI). We also performed a trial sequential analysis.

RESULTS

We included 15 articles (17 trials) comprising 2,290 patients in the systematic review. Compared with the direct laryngoscopy, indirect laryngoscopy improved success rate (RR, 1.15; 95% CI, 1.07 to 1.24; P = 0.0002; I2 = 88%), glottic visualization (RR, 1.76; 95% CI, 1.36 to 2.28; P < 0.001; I2 = 85%), and intubation time (WMD, -9.06 sec; 95% CI, -16.4 to -1.76; P = 0.01; I2 = 98%) in tracheal intubation. Trial sequential analysis showed that the total sample size was sufficient to analyze the success rate and intubation time.

CONCLUSION

In this systematic review, we found that the tracheal intubation success rate, glottic visualization, and intubation time were improved when novice operators used indirect laryngoscopy rather than direct laryngoscopy. Trial sequential analysis results indicated that the sample size was sufficient for examining the success rate and intubation time.

STUDY REGISTRATION

PROSPERO (CRD42022309045); first registered 4 September 2022.

Fibreoptic intubation: a commitment to an indispensable technique

Recent evidence has shown that fibreoptic intubation is still an indispensable technique for safe management of predicted difficult airways, despite the implementation of new technologies such as videolaryngoscopy. It is therefore our obligation as anaesthesia societies and as practicing anaesthetists to offer this technique to our patients in clearly designated situations.

Network meta-analysis of comparative efficacy and safety of intubation devices in children

To evaluate the comparative efficacy and safety of different intubation devices on intubation outcomes in pediatric intubation. We identified relevant studies from previous meta-analyses and literature retrieval in PubMed, EMBASE, and Cochrane Library. The primary outcome was the first-pass success (FPS), and the secondary outcome included the time to intubation (TTI) and the risk of local complications (LC). Network meta-analysis was performed using STATA 14.0. Twenty-three randomized comparative trials (RCTs) including 12 devices were included. Compared with Macintosh, Airtraq (odds ratio [OR] = 13.05, 95% confidence interval [CI] = 4.68 to 36.38), Miller (OR = 4.77, 95%CI = 1.32 to 17.22), Glidescope (OR = 2.76, 95%CrI = 1.60 to 4.75) and McGrath (OR = 4.61, 95%CI = 1.18 to 17.99) obtained higher PFS. Meanwhile, Airtraq was superior to Glidescope (OR = 0.21, 95%CI = 0.07 to 0.65) for PFS. For TTI, Canada was superior to other intubation devices, as well as CMAC was superior to TruViewEVO2, Glidescope, and StorzDCI. Airtraq lowered the risk of LC compared with Macintosh and Pentax but there was no statistical difference between Airtraq and KingVision. Airtraq may be the optimal option for FPS, Canada for TTI, and KingVision for LC in pediatric intubation.

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.

Videolaryngoscopy vs. flexible fibrescopy for tracheal intubation in patients with cervical spine immobilisation: a randomised controlled trial

In patients with cervical spine immobilisation, tracheal intubation devices other than a direct laryngoscope are frequently used to facilitate tracheal intubation and avoid related complications. In this randomised controlled trial, we compared videolaryngoscopic and fibrescopic tracheal intubation in patients with a cervical collar. Tracheal intubation was performed using either a videolaryngoscope with a non-channelled Macintosh blade (n = 166) or a flexible fibrescope (n = 164) in patients having elective cervical spine surgery whose neck was immobilised with a cervical collar to simulate a difficult airway. The primary outcome was the first attempt success rate of tracheal intubation. Secondary outcomes were the overall success rate of tracheal intubation; time to tracheal intubation; use of additional airway manoeuvres; and incidence and severity of tracheal intubation-related airway complications. First attempt success rate was higher in the videolaryngoscope group than in the fibrescope group (164/166 (98.8%) vs. 149/164 (90.9%), p = 0.003). Tracheal intubation was successful within three attempts in all patients. Median (IQR [range]) time to tracheal intubation was shorter (50.0 (41.0-72.0 [25.0-170.0]) s vs. 81.0 (65.0-107.0 [24.0-178.0]) s, p < 0.001) and additional airway manoeuvres were less frequent (30/166 (18.1%) vs. 91/164 (55.5%), p < 0.001) in the videolaryngoscope group compared with the fibrescope group. The incidence and severity of intubation-related airway complications were not different between the two groups. When performing tracheal intubation in patients with a cervical collar, videolaryngoscopy with a non-channelled Macintosh blade was superior to flexible fibrescopy.

Cervical spine movements during laryngoscopy and orotracheal intubation: a systematic review and meta-analysis

BACKGROUND

Airway management is challenging in trauma patients because of the fear of worsening cervical spinal cord damage. Video-integrated and optic-integrated devices and intubation laryngeal mask airways have been proposed as alternatives to direct laryngoscopy with the Macintosh laryngoscope (MAC). We performed a meta-analysis to clarify which devices cause less cervical movement during airway management.

METHODS

We searched MEDLINE, Cochrane Central, Embase and LILACS from inception to January 2022. We selected randomised controlled trials comparing alternative devices with the MAC for cervical movement from C0 to C5 in adult patients, evaluated by radiological examination. Additionally, cervical spine immobilisation (CSI) techniques were evaluated. We used the Cochrane Risk of Bias Tool to evaluate the risk of bias, and the principles of the Grading of Recommendations, Assessment, Development, and Evaluations system to assess the quality of the body of evidence.

RESULTS

Twenty-one studies (530 patients) were included. Alternative devices caused statistically significantly less cervical movement than MAC during laryngoscopy with mean differences of -3.43 (95% CI -4.93 to -1.92) at C0-C1, -3.19 (-4.04 to -2.35) at C1-C2, -1.35 (-2.19 to -0.51) at C2-C3, and -2.61 (-3.62 to -1.60) at C3-C4; and during intubation: -3.60 (-5.08 to -2.12) at C0-C1, -2.38 (-3.17 to -1.58) at C1-C2, -1.20 (-2.09 to -0.31) at C2-C3. The Airtraq and the Intubation Laryngeal Mask Airway caused statistically significant less movement than MAC restricted to some cervical segments, as well as CSI. Heterogeneity was low to moderate in most results. The quality of the body of evidence was 'low' and 'very low'.

CONCLUSIONS

Compared with the MAC, alternative devices caused less movement during laryngoscopy (C0-C4) and intubation (C0-C3). Due to the high risk of bias and the very low grade of evidence of the studies, further research is necessary to clarify the benefit of each device and to determine the efficacy of cervical immobilisation during airway management.

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).

A test prototype of a novel flexible video laryngoscope and preliminary verification in a difficult airway management simulator

Background

To verify a test prototype of a novel flexible video laryngoscope in a difficult airway management simulator and to compare the efficacy of the flexible video laryngoscope with that of a conventional video laryngoscope.

Methods

Fifteen clinical anesthesiologists performed endotracheal intubation with a flexible video laryngoscope and a conventional video laryngoscope in a difficult airway management simulator in the neutral position with intermediate and difficult mouth opening. The rate of intubation success, intubation time, and classification of glottic exposure were recorded. After endotracheal intubation, participants were asked to assess the difficulty of intubation of the two laryngoscopes.

Results

The success rate of endotracheal intubation with flexible video laryngoscope was significantly higher than that with video laryngoscope in neutral positions with both intermediate (P = 0.025) and difficult (P = 0.005) mouth opening. The Cormack Lehane score of the flexible video laryngoscope was significantly lower than that of the video laryngoscope in the neutral position with intermediate mouth opening (P < 0.001) and difficult mouth opening (P < 0.001). There was no significant difference in intubation time in the neutral position with intermediate mouth opening (P = 0.460) or difficult mouth opening (P = 0.078). The difficulty score of endotracheal intubations with the flexible video laryngoscope was also significantly lower than that of the video laryngoscope in the neutral position with intermediate mouth opening (P = 0.001) and difficult mouth opening (P = 0.001).

Conclusions

Compared with conventional video laryngoscopy, flexible video laryngoscopy can provide superior glottic exposure and improve the success rate of intubation in a difficult airway management simulator.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12938-022-01043-1.

Airway management in patients with suspected or confirmed traumatic spinal cord injury: a narrative review of current evidence

Around 1 million people sustain a spinal cord injury each year, which can have significant psychosocial, physical and socio‐economic consequences for patients, their families and society. The aim of this review is to provide clinicians with a summary of recent studies of direct relevance to the airway management of patients with confirmed or suspected traumatic spinal cord injury to promote best clinical practice. All airway interventions are associated with some degree of movement of the cervical spine; in general, these are very small and whether these are clinically significant in terms of impingement of the spinal cord is unclear. Manual in‐line stabilisation does not effectively immobilise the cervical spine and increases the likelihood of difficult and failed tracheal intubation. There is no clear evidence of benefit of awake tracheal intubation techniques in terms of prevention of secondary spinal cord injury. Videolaryngoscopy appears to cause a similar degree of cervical spine displacement as flexible bronchoscope‐guided tracheal intubation and is an appropriate alternative approach. Direct laryngoscopy does cause a slightly greater degree of cervical spinal movement during tracheal intubation than videolaryngoscopy, but this does not appear to increase the risk of spinal cord compression. The risk of spinal cord injury during tracheal intubation appears to be minimal even in the presence of gross cervical spine instability. Depending on the clinical situation, practitioners should choose the tracheal intubation technique with which they are most proficient and that is most likely to minimise cervical spine movement.

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.

Videolaryngoscopes versus direct laryngoscopes in children: Ranking systematic review with network meta-analyses of randomized clinical trials

BACKGROUND

Videolaryngoscopes improve tracheal intubation in adult patients, but we currently do not know whether they are similarly beneficial for children. We designed this ranking systematic review to compare individual video and direct laryngoscopes for efficacy and safety of orotracheal intubation in children.

METHODS

We searched PubMed and five other databases on January 27, 2021. We included randomized clinical trials with patients aged ≤18 years, comparing different laryngoscopes for the outcomes: failed first intubation attempt; failed intubation within two attempts; failed intubation; glottic view; time for intubation; complications. In addition, we assessed the quality of evidence according to GRADE recommendations.

RESULTS

We included 46 studies in the meta-analyses. Videolaryngoscopy reduced the risk of failed first intubation attempt (RR = 0.43; 95% CI: 0.31-0.61; p = .001) and failed intubation within two attempts (RR = 0.33; 95% CI: 0.33-0.33; p < .001) in children aged <1 year. Videolaryngoscopy also reduced the risk of major complications in both children aged <1 year (RR = 0.33; 95% CI: 0.12-0.96; p = .046) and children aged 0-18 years (RR = 0.40; 95% CI: 0.25-0.65; p = .002). We did not find significant difference between videolaryngoscopy and direct laryngoscopy for time to intubation in children aged <1 year (MD = -0.95 s; 95% CI: -5.45 to 3.57 s; p = .681), and children aged 0-18 years (MD = 1.65 s; 95% CI: -1.00 to 4.30 s; p = .222). Different videolaryngoscopes were associated with different performance metrics within this meta-analysis. The overall quality of the evidence ranged from low to very low.

CONCLUSION

Videolaryngoscopes reduce the risk of failed first intubation attempts and major complications in children compared to direct laryngoscopes. However, not all videolaryngoscopes have the same performance metrics, and more data is needed to clarify which device may be better in different clinical scenarios. Additionally, care must be taken while interpreting our results and rankings due to the available evidence's low or very low quality.

Intubation biomechanics: Computational modeling to identify methods to minimize cervical spine motion and spinal cord strain during laryngoscopy and tracheal intubation in an intact cervical spine

STUDY OBJECTIVE

To minimize the risk of cervical spinal cord injury in patients who have cervical spine pathology, minimizing cervical spine motion during laryngoscopy and tracheal intubation is commonly recommended. However, clinicians may better aim to reduce cervical spinal cord strain during airway management of their patients. The aim of this study was to predict laryngoscope force characteristics (location, magnitude, and direction) that would minimize cervical spine motions and cord strains.

DESIGN

We utilized a computational model of the adult human cervical spine and spinal cord to predict intervertebral motions (rotation [flexion/extension] and translation [subluxation]) and cord strains (stretch and compression) during laryngoscopy.

INTERVENTIONS

Routine direct (Macintosh) laryngoscopy conditions were defined by a specific force application location (mid-C3 vertebral body), magnitude (48.8 N), and direction (70 degrees). Sixty laryngoscope force conditions were simulated using 4 force locations (cephalad and caudad of routine), 5 magnitudes (25-200% of routine), and 3 directions (50, 70, 90 degrees).

MAIN RESULTS

Under all conditions, extension at Oc-C1 and C1-C2 were greater than in all other cervical segments. Decreasing force magnitude to values reported for indirect laryngoscopes (8-17 N) decreased cervical extension to ~50% of routine values. The cervical cord was most likely to experience potentially injurious compressive strain at C3, but force magnitudes ≤50% of routine (≤24.4 N) decreased strain in C3 and all other cord regions to non-injurious values. Changing laryngoscope force locations and directions had minor effects on motion and strain.

CONCLUSIONS

The model predicts clinicians can most effectively minimize cervical spine motion and cord strain during laryngoscopy by decreasing laryngoscope force magnitude. Very low force magnitudes (<5 N, ~10% of routine) are necessary to decrease overall cervical extension to <50% of routine values. Force magnitudes ≤24.4 N (≤50% of routine) are predicted to help prevent potentially injurious compressive cord strain.

Challenges and outcomes in airway management outside the operating room

PURPOSE OF REVIEW

Airway management outside the operating room poses unique challenges that every clinician should recognize. These include anatomic, physiologic, and logistic challenges, each of which can contribute to complications and lead to poor outcomes. Recognizing these challenges and highlighting known outcome data may better prepare the team, making this otherwise daunting procedure safer and potentially improving patient outcomes.

RECENT FINDINGS

Newer intubating techniques and devices have made navigating anatomic airway challenges easier. However, physiological challenges during emergency airway management remain a cause of poor patient outcomes. Hemodynamic collapse has been identified as the most common peri-intubation adverse event and a leading cause of morbidity and mortality associated with the procedure.

SUMMARY

Emergency airway management outside the operating room remains a high-risk procedure, associated with poor outcomes. Pre-intubation hemodynamic optimization may mitigate some of the risks, and future research should focus on identification of best strategies for hemodynamic optimization prior to and during this procedure.

Cervical spine immobilization does not interfere with nasotracheal intubation performed using GlideScope videolaryngoscopy: a randomized equivalence trial

GlideScope-assisted nasotracheal intubation (NTI) has been proposed as an alternative to difficult orotracheal intubation for critical patients or those under cervical immobilization. We evaluated the difficulty of performing NTI using GlideScope under cervical orthosis. A total of 170 patients scheduled for elective cervical spinal surgery that required NTI were randomized to receive cervical immobilization using a cervical collar (collar group) or no cervical immobilization at all (control group) before anesthetic induction (group assignment at 1:1 ratio). All NTI during anesthetic induction were performed using the GlideScope. The primary outcome was time to intubation. The secondary outcomes were ease of intubation, including the necessity of auxiliary manipulations to assist intubation, and the nasotracheal intubation difficulty scale (nasoIDS). An exploratory analysis identified morphometric parameters as predictors of time to intubation, the necessity of auxiliary manipulations, and a nasoIDS score ≥ 4. For time to intubation, the mean difference (collar group-control) was - 4.19 s, with a 95% confidence interval (CI) of - 13.9 to 5.52 that lay within our defined equivalence margin of 16 s. Multivariate regressions precluded the association of cervical immobilization with a necessity for auxiliary manipulations (adjusted odds ratio [aOR] 0.53, 95% CI [0.26-1.09], P = 0.083) and a nasoIDS ≥ 4 (aOR 0.94 [0.84-1.05], P = 0.280). Among all morphometric parameters, the upper lip bite test class was predictive of a longer time to intubation (all analyses relative to class 1, 14 s longer for class 2, P = 0.032; 24 s longer for class 3, P = 0.070), increased necessity for auxiliary manipulation (aOR 2.29 [1.06-4.94], P = 0.036 for class 2; aOR 6.12 [1.04-39.94], P = 0.045 for class 3), and nasoIDS ≥ 4 (aOR 1.46 [1.14-1.89], P = 0.003 for class 3).The present study demonstrated that GlideScope achieved NTI in patients with or without cervical immobilization equivalently with respect to intubation time and ease.

Split Type Postman videolaryngoscope: The newer device versus the standard Macintosh laryngoscope in simulated difficult airway – A new hope for difficult intubation scenarios

Background and Aims:

Methods:

Results:

Conclusion:

Videolaryngoscopy vs. direct Macintosh laryngoscopy in tracheal intubation in adults: a ranking systematic review and network meta-analysis

Videolaryngoscopes are thought to improve glottic view and facilitate tracheal intubation compared with the Macintosh direct laryngoscope. However, we currently do not know which one would be the best choice in most patients undergoing anaesthesia. We designed this systematic review with network meta-analyses to rank the different videolaryngoscopes and the Macintosh direct laryngoscope. We conducted searches in PubMed and a further five databases on 11 January 2021. We included randomised clinical trials with patients aged ≥16 years, comparing different videolaryngoscopes, or videolaryngoscopes with the Macintosh direct laryngoscope for the outcomes: failed intubation; failed first intubation attempt; failed intubation within two attempts; difficult intubation; percentage of glottic opening seen; difficult laryngoscopy; and time needed for intubation. We assessed the quality of evidence according to GRADE recommendations and included 179 studies in the meta-analyses. The C-MAC and C-MAC D-Blade were top ranked for avoiding failed intubation, but we did not find statistically significant differences between any two distinct videolaryngoscopes for this outcome. Further, the C-MAC D-Blade performed significantly better than the C-MAC Macintosh blade for difficult laryngoscopy. We found statistically significant differences between the laryngoscopes for time to intubation, but these differences were not considered clinically relevant. The evidence was judged as of low or very low quality overall. In conclusion, different videolaryngoscopes have differential intubation performance and some may be currently preferred among the available devices. Furthermore, videolaryngoscopes and the Macintosh direct laryngoscope may be considered clinically equivalent for the time taken for tracheal intubation. However, despite the rankings from our analyses, the current available evidence is not sufficient to ensure significant superiority of one device or a small set of them over the others for our intubation-related outcomes.

Airway management in the adult patient with an unstable cervical spine

PURPOSE OF REVIEW

The ideal airway management of patients with unstable spinal injury presents a perennial challenge for anaesthesiologists. With competing interests, potentially catastrophic complications, and a scarcity of evidence to support common practices, it is an area rich with dogma and devoid of data. This review seeks to highlight recent evidence that improves our assurance that what we do to manage the airway in the unstable cervical spine is supported by data.

RECENT FINDINGS

The increasing range of available technology for intubation provides important opportunities to investigate the superiority (or otherwise) of various techniques - and a chance to challenge accepted practice. Long-held assumptions regarding spinal immobilisation in the context of airway management may require refinement as a true base of evidence develops.

SUMMARY

Video laryngoscopy may replace direct laryngoscopy as the default technique for endotracheal intubation in patients with suspected or confirmed spinal instability. Immobilisation of the unstable cervical spine, manually or with rigid cervical collars, is increasingly controversial. It may be that hard collars are used in specific circumstances, rather than as universal precaution in the future.There are no recent data of significantly high quality to warrant wholesale changes to recommended airway management practice and in the absence of new information, limiting movement (in the suspected or confirmed unstable cervical spine) remains the mainstay of clinical practice advice.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 2. Planning and implementing safe management of the patient with an anticipated difficult airway

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence is lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.