What are the criteria for a failed intubation?

Failed Intubation Criteria

Failed intubation is declared after a maximum of 3+1 attempts at tracheal intubation (three attempts by the initial operator, plus one final attempt by a more experienced colleague), at which point you must immediately move to Plan B and ensure emergency front-of-neck airway (eFONA) equipment is accessible 1.

Defining a Failed Intubation Attempt

Each attempt is defined as instrumentation with a device or introducer that either successfully places a tube in the trachea (confirmed by waveform capnography and visualization) or fails to do so 1. The key criteria are:

The 3+1 Rule (Most Current Standard)

• Maximum 3 attempts by the initial operator
• 1 final attempt only by a more experienced colleague
• Each subsequent attempt must involve a meaningful change (different laryngoscope, blade, introducer, operator, positioning, external laryngeal manipulation, removal of cricoid pressure, or optimizing neuromuscular blockade) 1
• Abandon any attempt immediately if hypoxemia occurs and prioritize oxygenation with facemask ventilation 1

Early Declaration of Failure

You can and should declare failed intubation before exhausting all 3+1 attempts if 1:

• You cannot identify changes that would improve success likelihood (e.g., impossible laryngoscopy despite optimal conditions)
• Further attempts would likely cause complications (e.g., airway obstruction, failure of facemask ventilation, airway trauma)

ASA Definition (Broader Framework)

The 2022 ASA guidelines define difficult or failed tracheal intubation more simply as: tracheal intubation requiring multiple attempts OR tracheal intubation that fails after multiple attempts 2. This aligns with the 3+1 principle but doesn't specify the exact number.

Critical Context from Real-World Data

Research shows that each successive attempt increases complication risk and decreases success probability 1. In a large tertiary care study, the incidence of failed intubation was 0.03% (14 cases in 42,805 surgeries), with poor glottic visualization (93%) and airway bleeding (36%) being the leading causes 3. Videolaryngoscopy showed 71-77% success as a rescue device 3.

Common Pitfalls to Avoid

• Don't waste attempts: Make the first attempt your best attempt with optimal positioning, equipment, and conditions 1
• Don't delay neuromuscular blockade: Administer it after induction; don't wait to confirm facemask ventilation first 1
• Don't persist beyond 3+1 attempts: This is a hard stop—declare failure and move to Plan B 1
• Don't ignore hypoxemia: Abandon the attempt immediately and restore oxygenation 1

What Happens After Failed Intubation

Once failed intubation is declared:

1. Move to Plan B (supraglottic airway device or facemask ventilation)
2. Prime eFONA equipment (make it immediately accessible)
3. Summon appropriate assistance 1
4. If you encounter "cannot intubate, cannot oxygenate" (failed intubation + failed facemask/supraglottic ventilation), proceed immediately to cricothyrotomy 4