Airway and Cervical Spine Injury

Reviewed and revised 11 December 2014

OVERVIEW

• about 30% of trauma patients (depending on the study) require intubation <30 minutes of arrival in ED
• airway management must take into account the risk of coexistent cervical spine injury, the mantra being “airway management with cervical spine stabilisation”
  • 1-5% risk of cervical spine injury in major trauma (2.4% in the NEXUS study), and 7-14% of these are unstable
  • 10% of trauma patients with GCS <9 have a cervical spine injury

MANUAL IN-LINE STABILISATION (MILS)

Cervical spine protection is indicated in the following trauma settings:

• Neck pain or neurological symptoms (OR58 for focal neurological deficit)
• Altered level of consciousness (OR14 for decreased level of consciousness)
• Significant blunt injury above the level of the clavicles (OR8.5 for severe TBI)

MILS is performed by an assistant during airway management to maintain a neutral position and prevent inadvertent movement of the head and neck, by either:

• crouching beside the intubator with hands placed on the patient’s mastoid processes or cradling the occiput
• standing beside the patient in front of the intubator with hands placed on the sides of the patient’s head and forearms resting on the patient’s chest
• traction must not be applied
• note that there is no universal definition of neutral position

MILS is replaced by a cervical collar, lateral blocks/ sand bags, and head and chin straps once the airway is secure

• hard collars should not be used during airway management
• nearly 2/3 of patients on a hardboard with collar, straps and sandbags have grade 3 or 4 airways
• hard collars also limit mouth opening
• while MILS worsens laryngoscopic view 45% of the time, a lower proportion (22%) have grade 3 airways
• MILS decreases cervical spine movements more effectively that collars during airway management, though it is unclear if that translates into injury at the sire of movement
• 56% of patients improve their Cormack-Lehane grade when their hard collar is switched to MILS

CERVICAL SPINE MOVEMENT AND AIRWAY MANAGEMENT

• the classic ‘sniffing position’ involves near full extension at the atlanto-occipital and atlanto-axial joints and flexion of the lower C-spine vertebrae
• the stable spine is that which
  • it is generally assumed that physiological degrees of movement seen in the normal spine are acceptable in cervical spine injury
  • however, this is not certain
• most airway manoeuvres appear to cause cervical spine vertebral movements by 2-4 mm
  • pre-intubation manoeuvres such as bag-valve-mask ventilation causes the most movement (2.9 mm)
  • oral intubation causes movements of about 1.5 mm
• there is no defined extent of cervical spine movement known to be dangerous in different cervical spine injuries

NEUROLOGICAL DETERIORATION DUE TO INTUBATION

• neurological deterioration due to oral endotracheal intubation in patients with unstable cervical spine injuries is very rare
• airway manoeuvres, with the use of MILS, performed with reasonable care are highly unlikely to cause significant cervical spine movmeent
• data supporting or refuting claims about the risks involved are inadequate
  • studies of neurological deterioration associated with endotracheal intubation are largely small retrospective studies
  • the majority of claims of neurological deterioration are based on a temporal association and in many cases causation is highly unlikely
• neurological deterioration can be due to ascending myelopathy
  • may be a sequela of the the primary injury
  • can occur independent of subsequent clinical interventions such as airway manoeuvres
• it is unlikely that laryngeal manoeuvres (e.g. cricoid pressure, BURP) exacerbate cervical spine injury directly

INTUBATION OPTIONS

These include:

• direct laryngoscopy (DL)
• video laryngoscopy (VL)
• awake fiber-optic intubation(AFOI)
• supraglottic airways (SGA) such as laryngeal mask airways (LMA)

	ADVANTAGES	DISADVANTAGES
DL	Fast Tried and tested, widely available Can use bougie/ stylet No evidence that it is worse than other methods in practice	operator dependent more difficult when MILS is applied
VL	Less mouth opening required (some devices e.g. C-MAC, McGrath)) Some devices can be used as direct laryngoscopes (e.g. C-MAC)	more mouth opening required (e.g. Pentax) hindered by blood and secretionsrequires expertise and equipment slower one study in trauma patients suggested worse outcomes with glidescope than with direct laryngoscopy
AFOI	allows documentation of neurological exam before and after minimal risk of displacement the stated preferred method in some surveys of anaesthetists	failure can lead to morbidity requires a cooperative patient hindered by blood and secretions requires expertise and equipment (in surveys even the anaesthetists stating this is the preferred method admit to less confidence in their skills!) no data supporting theoretic benefits
SGA	Fast More effective ventilation than BVM May faciltate intubation (e.g. iLMA) Useful rescue device if unable to intubate	not a definitive airway – risk of aspiration uncertainty about degree of cervical spine movement

AN APPROACH

• rapid sequence intubation is a safe and acceptable approach in the trauma patient with suspected or known cervical spine injury
• perform manual in-line stabilistation (MILS) and remove the hard collar
• use a bougie as first line approach with direct or video laryngoscopy (endotracheal tube with stylet is an alternative)
• Awake fiber-optic intubation is an alternative if the necessary expertise and equipment is available, the patient is cooperative and the situation is not a true emergency

References and Links

Journal Articles

• Austin N, Krishnamoorthy V, Dagal A. Airway management in cervical spine injury. Int J Crit Illn Inj Sci. 2014 Jan;4(1):50-6. doi: 10.4103/2229-5151.128013. PubMed PMID: 24741498; PubMed Central PMCID: PMC3982371.
• Aziz M. Use of video-assisted intubation devices in the management of patients with trauma. Anesthesiol Clin. 2013 Mar;31(1):157-66. doi: 10.1016/j.anclin.2012.10.001. Epub 2012 Nov 3. Review. PubMed PMID: 23351541.
• Crosby ET. Airway management in adults after cervical spine trauma. Anesthesiology. 2006 Jun;104(6):1293-318. Review. PubMed PMID: 16732102. [Free Full Text]
• Michailidou M, O’Keeffe T, Mosier JM, Friese RS, Joseph B, Rhee P, Sakles JC. A Comparison of Video Laryngoscopy to Direct Laryngoscopy for the Emergency Intubation of Trauma Patients. World J Surg. 2014 Oct 28. [Epub ahead of print] PubMed PMID: 25348885.
• Durga P, Sahu BP. Neurological deterioration during intubation in cervical spine disorders. Indian J Anaesth [serial online] 2014 [cited 2014 Dec 22];58:684-92. Available at URL: http://www.ijaweb.org/text.asp?2014/58/6/684/147132
• Ollerton JE, Parr MJ, Harrison K, Hanrahan B, Sugrue M. Potential cervical spine injury and difficult airway management for emergency intubation of trauma adults in the emergency department–a systematic review. Emerg Med J. 2006 Jan;23(1):3-11. Review. PubMed PMID: 16373795; PubMed Central PMCID: PMC2564122.
• Yeatts DJ, Dutton RP, Hu PF, Chang YW, Brown CH, Chen H, Grissom TE, Kufera JA, Scalea TM. Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial. J Trauma Acute Care Surg. 2013 Aug;75(2):212-9. doi: 10.1097/TA.0b013e318293103d. PubMed PMID: 23823612.