What is the recommended neck position for intubation?

Recommended Neck Position for Intubation

The sniffing position (neck flexion with head extension) is the recommended standard position for intubation, as it provides optimal laryngeal visualization and increases the success rate of first-pass intubation. 1

Optimal Positioning Technique

• The sniffing position consists of flexion of the lower cervical spine and extension of the upper cervical spine (head extension), which can be achieved by placing an appropriately sized cushion under the occiput 1
• For optimal positioning, the patient's head should be elevated approximately 7-10 cm from the neutral plane with neck flexion, followed by maximal extension of the head at the atlanto-occipital joint 2, 3
• When tolerated, tilt the patient's head up 25-30° to improve upper airway patency, increase functional residual capacity, and potentially reduce aspiration risk 1
• Ensure the bed mattress is as firm as possible to optimize head extension and access to the cricothyroid membrane if needed 1

Evidence Supporting the Sniffing Position

• The sniffing position significantly improves the Intubation Difficulty Scale (IDS) score compared to simple head extension alone, requiring less lifting force and reduced need for external laryngeal manipulation 3
• While perfect anatomical alignment of the mouth axis, pharyngeal axis, and laryngeal axis is not achievable in any position, the sniffing position optimizes the line of vision to the larynx 4
• Further head elevation (additional neck flexion) beyond the standard sniffing position may further improve glottic visualization and reduce intubation difficulty in some patients 2

Special Considerations for Different Patient Populations

• For obese patients, ramping (positioning with the external auditory meatus level with the sternal notch) is recommended with the head extended such that the face is horizontal 1, 5
• For patients with suspected cervical spine injury, maintain a neutral head and neck position or tilt the whole bed head-up rather than flexing the neck 1
• In critically ill patients, when feasible, a semi-Fowler position (head and trunk inclined) may improve preoxygenation through increased functional residual capacity, though evidence regarding its effect on first-pass success is mixed 1

Common Pitfalls and Practical Tips

• Avoid inadequate head elevation, which fails to achieve proper neck flexion 5
• Avoid excessive head elevation, which can worsen the laryngeal view 5
• Use horizontal alignment of the external auditory meatus with the sternum as a marker for proper positioning in both obese and non-obese patients 5
• A triangular-shaped pillow may provide better head extension compared to a regular pillow, improving laryngoscopic view and facilitating endotracheal intubation 6
• Consider using optimal external laryngeal manipulation (OELM) or BURP (backward, upward, rightward pressure on the thyroid cartilage) to further improve laryngeal view if needed 1, 7

Alternative Approaches When Standard Positioning Fails

• If first attempt with standard sniffing position fails, consider alternative direct laryngoscopes such as McCoy or straight laryngoscopes 1
• Use of a bougie (tracheal tube introducer) is recommended when the best view of the larynx is Cormack-Lehane grade 3 1
• Limit total intubation attempts to 3-4 to avoid airway trauma and worsening edema 7
• Have a clear plan for failed intubation, including rescue techniques with supraglottic airway devices and front-of-neck airway access if needed 1