Airtraq® vs. fibreoptic intubation in patients with an unstable cervical spine fracture: A neurophysiological study

Radiographic Predictors of Difficult Fiberscopic Intubation During General Anesthesia in Patients With a Cervical Collar to Simulate a Difficult Airway

BACKGROUND

Predictors of difficult fiberscopic intubation have not been fully elucidated. This study focused on identifying radiographic predictors of difficult fiberscopic intubation during general anesthesia in patients with a cervical collar.

METHODS

This retrospective study included unconscious patients who underwent orotracheal intubation using a flexible fiberscope while wearing a cervical collar to simulate a difficult airway. Easy fiberscopic intubation was defined as successful fiberscopic intubation within 120 seconds on the first attempt without desaturation below 90%. The patients were divided into easy (n=133) and difficult (n=24) fiberscopic intubation groups. Demographic, mask ventilation-related, upper airway-related, and radiographic variables measured on sagittal images of preoperative cervical x-ray and magnetic resonance imaging were analyzed.

RESULTS

The difficult fiberscopic intubation group had a smaller oral cavity area (2.1 [1.2-2.5] vs. 2.9 [2.1-3.7] cm2, P<0.001), higher tongue area divided by oral cavity area (9.3 [6.5-13.3] vs. 6.4 [4.6-8.3], P<0.001), smaller epiglottis angle (33±10° vs. 37±8°, P=0.02), and longer skin-glottis distance (1.3 [1.1-1.6] vs. 1.1 [1.0-1.3] cm, P=0.004). Tongue area/oral cavity area (odds ratio per 1 [95% CI]: 1.24 [1.09-1.40]) and skin-glottis distance (odds ratio per 1 cm [95% CI]: 13.0 [2.69-62.4]) were independently associated with the difficulty in fiberscopic intubation.

CONCLUSIONS

High tongue area/oral cavity area and long skin-glottis distance were predictive of difficult fiberscopic intubation during general anesthesia in patients with a cervical collar.

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.

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.

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.

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.