What is the purpose of the jaw thrust maneuver or head tilt-chin lift technique in an unconscious patient with a potential cervical spine injury?

Purpose of Jaw Thrust and Head Tilt-Chin Lift in Unconscious Patients with Potential Cervical Spine Injury

The primary purpose of these airway maneuvers is to open the airway by relieving upper airway obstruction caused by posterior displacement of the tongue and soft tissues in unconscious patients, thereby establishing airway patency to enable adequate ventilation and oxygenation. 1

Fundamental Airway Physiology

In unconscious patients, loss of muscle tone causes the tongue and soft palate to fall backward against the posterior pharyngeal wall, creating complete or partial airway obstruction. 1 Both the jaw thrust and head tilt-chin lift maneuvers physically displace these structures anteriorly to restore the airway opening. 1

Technique Selection Based on Cervical Spine Injury Risk

When Cervical Spine Injury is NOT Suspected

Use the head tilt-chin lift maneuver as the primary technique. 1 This is the standard approach for both healthcare providers and trained lay rescuers when there is no evidence of head or neck trauma. 1

When Cervical Spine Injury IS Suspected or Cannot Be Ruled Out

Use the jaw thrust maneuver exclusively as the initial airway opening technique. 1 The jaw thrust produces significantly less cervical spine movement compared to head tilt-chin lift:

• Angular motion: Jaw thrust causes mean 4.8° flexion-extension versus 14.7° with head tilt-chin lift (approximately 3 times less movement) 1, 2
• Rotational movement: 2.4° versus 5.4° 1
• Lateral bending: 2.5° versus 7.4° 1
• Space available for cord (SAC): Jaw thrust maintains 1.6 mm versus 1.1 mm with chin lift 1

These measurements come from cadaveric studies using unstable C1-C2 injuries (odontoid type-2 fractures) with 3D electromagnetic motion analysis. 1, 2

Critical Decision Algorithm When Jaw Thrust Fails

If the jaw thrust does not adequately open the airway and allow ventilation to occur, you must switch to the head tilt-chin lift maneuver even in cases of potential spinal injury. 1 This represents a fundamental principle in resuscitation: maintaining a patent airway and providing adequate ventilation are absolute priorities in CPR, and the need to open the airway outweighs the risk of further spinal damage in the cardiac arrest patient. 1

The American Heart Association explicitly states this hierarchy: "Because maintaining a patent airway and providing adequate ventilation are priorities in CPR (Class I, LOE C), use the head tilt–chin lift maneuver if the jaw thrust does not adequately open the airway." 1

Concurrent Spinal Protection Measures

While performing either maneuver, maintain manual spinal motion restriction by placing one hand on either side of the patient's head to hold it still, rather than using immobilization devices. 1 Spinal immobilization devices can interfere with maintaining a patent airway and should be avoided by untrained rescuers. 1

For patients requiring airway management with confirmed cervical spine injury, remove only the anterior portion of the cervical collar during airway procedures while maintaining manual in-line stabilization. 1, 3, 4

Common Pitfalls to Avoid

• Never use head tilt-chin lift as the first maneuver when cervical spine injury is suspected, as it produces three times more cervical movement than jaw thrust and can cause catastrophic cord injury. 3
• Do not persist with an ineffective jaw thrust if it fails to produce adequate chest rise—the priority is oxygenation and ventilation, not theoretical spinal protection. 1
• Avoid high-flow nasal oxygen in patients with suspected basilar skull fractures due to risk of pneumocephalus. 1, 4