Cervical Spine Movement in a Cadaveric Model of Severe Spinal Instability: A Study Comparing Tracheal Intubation with 4 Different Laryngoscopes

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.

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.

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.

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.

Comparison of video-stylet and video-laryngoscope for endotracheal intubation in adults with cervical neck immobilisation: A meta-analysis of randomised controlled trials

BACKGROUND

The efficacy of video-stylet versus video-laryngoscope for tracheal intubation in patients with cervical spine immobilisation, which is known to impede the intubation process, remains unclear.

METHODS

We searched electronic databases including EMBASE, MEDLINE, Google Scholar, and Cochrane Library for randomised controlled trials comparing video-stylets with video-laryngoscopes in human subjects with cervical spine immobilisation from inception to the 25^th of January 2021. The primary outcome was the rate of successful first-attempt intubation, while secondary outcomes included overall intubation success rate, time for successful intubation, and risk of tissue damage.

RESULTS

Five trials (709 patients) published between 2009 and 2020 met the inclusion criteria. There were four types of video-stylets and three types of video-laryngoscopes examined. Hard cervical collar was applied in four studies, while manual inline stabilisation was used in one study for cervical immobilisation. There was no difference in successful first-attempt intubation rate between the video-stylet and the video-laryngoscope groups [risk ratio (RR) = 0.96, 95% CI: 0.90-1.03, p = 0.3; I² = 47%] (5 trials, 709 patients). The overall success rate (RR = 0.98, 95% CI: 0.96-1.0, p = 0.05; I² = 0%), intubation time [mean difference (MD) = 5.24, 95% CI: -8.95 to 19.43, p = 0.47; I² = 92%], and risk of tissue damage (RR = 0.87, 95% CI: 0.26-2.85, p = 0.81; I² = 39%) were also comparable between the two groups.

CONCLUSIONS

This study validates the efficacy of both video-stylets and video-laryngoscopes for tracheal intubation in the situation of cervical spine immobilisation. Further large-scale trials are warranted to support our findings in this clinical setting.

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.

Neuroanesthesiology Update

This review summarizes the literature published in 2020 that is relevant to the perioperative care of neurosurgical patients and patients with neurological diseases as well as critically ill patients with neurological diseases. Broad topics include general perioperative neuroscientific considerations, stroke, traumatic brain injury, monitoring, anesthetic neurotoxicity, and perioperative disorders of cognitive function.