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# The unanticipated difficult airway: plans A to D

- Crisis

When a breathing tube will not go in, a fixed sequence of backup plans keeps oxygen flowing until the patient is safe.

Updated Nov 13, 2026

## Key points

- The goal is oxygenation, not intubation: a well-oxygenated patient with no tube is safe.
- Limit attempts at each plan (a small fixed number, the last by the most experienced person) because repeated laryngoscopy swells the airway.
- Plan B uses a supraglottic airway, preferably second-generation; Plan C is face-mask ventilation; then wake the patient if you can.
- Falling saturation despite supraglottic airway and mask attempts means declaring «cannot intubate, cannot oxygenate» and moving to front-of-neck access.
- Capnography with a sustained waveform is the only reliable confirmation that a tube is in the trachea.

On this page

- The basics Key points
- What it is
- How to recognise it
- Why it happens
- What to do at once
- The plans of a difficult airway algorithm and what each one aims for
- Costly mistakes
- Next step
- Memory aid
- Elsewhere in DurgiPedia

- Study Test yourself

- Connections Connections

## What it is

An unanticipated difficult airway is the moment, after induction of anaesthesia, when tracheal intubation fails despite a normal-looking assessment. The danger is not the failed tube itself but falling oxygen levels while the team keeps trying. Difficult airway guidelines therefore organise the response as a short chain of plans, each with a limited number of attempts. Plan A is tracheal intubation with the best first attempt: good positioning, preoxygenation, full muscle relaxation and, increasingly, a videolaryngoscope and a bougie. If it fails, Plan B is to oxygenate through a supraglottic airway, ideally a second-generation device with a gastric drain channel, and then decide whether to wake the patient, proceed carefully, or intubate through the device. If that fails too, Plan C is face-mask ventilation, with two hands, oral or nasal airways and full paralysis, and a decision to wake the patient if oxygenation is possible. When none of these oxygenates, the patient is in a «cannot intubate, cannot oxygenate» situation and Plan D is emergency front-of-neck access. Throughout, the priority is oxygenation, not intubation, and declaring failure early and calling for help are skills, not weaknesses.

## How to recognise it

- Laryngoscopy shows little or none of the glottis, or the tube or bougie will not pass despite a good view.
- Several attempts have failed, or the person intubating says it is difficult.
- Oxygen saturation is falling, or no sustained capnography trace appears after the tube is placed.
- Bleeding, swelling or secretions build up in the airway with each attempt.
- Face-mask ventilation becomes difficult: poor chest rise, large leak, no capnography trace.

## Why it happens

- Airway assessment is imperfect, so many difficult airways are not predicted beforehand.
- Each laryngoscopy can cause oedema and bleeding, turning a difficult airway into an impossible one.
- After induction, the apnoeic patient consumes oxygen stores; obesity, pregnancy, children and critical illness shorten the safe time.
- Task fixation: the team keeps trying to intubate and loses track of time and saturation.

## What to do at once

- Call for help and name the problem aloud — a clear declaration focuses the team and brings an experienced colleague and the difficult airway trolley.
- Keep oxygen going between attempts with face mask and nasal oxygen — oxygenation buys time; intubation is only a means to it.
- Optimise Plan A once: reposition, adjust blade, use a videolaryngoscope and a bougie, external laryngeal pressure — each change must alter something.
- Stop after a limited number of attempts and insert a supraglottic airway (Plan B) — repeated laryngoscopy swells the airway and worsens the next try.
- If the supraglottic airway oxygenates, stop and think: wake the patient, proceed, or intubate through it — the safest choice depends on the urgency.
- If it fails, use two-person face-mask ventilation with adjuncts and full paralysis (Plan C) — better seal and relaxed muscles open the airway.
- If mask ventilation works, wake the patient: reverse the neuromuscular block if possible — return of spontaneous breathing is the safest exit.
- If nothing oxygenates and saturation falls, declare «cannot intubate, cannot oxygenate» and start front-of-neck access (Plan D) — delay causes brain injury.

## The plans of a difficult airway algorithm and what each one aims for

| Plan | What is done | Goal and exit |
| --- | --- | --- |
| A | Tracheal intubation with optimal position, preoxygenation, full relaxation, videolaryngoscope and bougie | A tube confirmed by capnography; limited attempts, then move on |
| B | Supraglottic airway, preferably second-generation | Oxygenation; then wake, proceed or intubate through the device |
| C | Face-mask ventilation, two hands, oral or nasal airways, full paralysis | Oxygenation; then wake the patient |
| D | Emergency front-of-neck access (scalpel cricothyroidotomy) | Oxygenation when every other plan fails |

## Costly mistakes

- Making many attempts at intubation: each one swells the airway and uses up the safe apnoea time.
- Trusting chest movement, breath sounds or tube misting instead of a sustained capnography waveform.
- Not calling for help early, or calling only when saturation is already critically low.
- Repeating the same technique unchanged instead of changing device, position or operator.
- Delaying front-of-neck access while trying yet another device, or giving up because of fear of the procedure.

## Next step

- Once the patient is safe, decide with a senior whether surgery goes ahead, is postponed, or needs an awake technique next time.
- Watch for airway swelling, bleeding, aspiration and pneumothorax in recovery; extubate with a plan, as for a difficult airway.
- Document the grade of view, the devices tried, what worked and what failed, in a clear airway note.
- Tell the patient, give a written difficult airway alert, and inform the primary care doctor so future anaesthetists are warned.
- Debrief the team and report the event to the department's safety system.

## Memory aid

A for attempt, B for back-up device, C for can you mask, D for do the neck: each plan has an exit, and the exit is waking up.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main priority when intubation fails unexpectedly after induction?

Oxygenation, not intubation: keep oxygen going with mask, supraglottic airway or nasal oxygen, and call for help.

## Why are the attempts at intubation limited in difficult airway guidelines?

Each laryngoscopy can cause swelling and bleeding, worsening the next attempt and using up the safe apnoea time.

## What should usually happen once a supraglottic airway oxygenates the patient after failed intubation?

Stop and think: the usual safest choice is to wake the patient; proceeding or intubating through the device is chosen only if surgery is urgent.

## When is front-of-neck access indicated?

When intubation, supraglottic airway and face-mask ventilation all fail and oxygenation cannot be maintained: «cannot intubate, cannot oxygenate».

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anaesthesia/the-unanticipated-difficult-airway-plans-a-to-d/)

## Elsewhere in DurgiPedia

- [Bag-mask ventilation](https://durgical.com/en/clinical-skills/bag-mask-ventilation/)
- [Supraglottic airway devices](https://durgical.com/en/clinical-skills/supraglottic-airway-devices/)
- [Opening the airway: head tilt, jaw thrust and simple adjuncts](https://durgical.com/en/clinical-skills/opening-the-airway-head-tilt-jaw-thrust-and-simple-adjuncts/)
- [Emergency front-of-neck access: cricothyroidotomy and tracheostomy](https://durgical.com/en/ent/emergency-front-of-neck-access-cricothyroidotomy-and-tracheostomy/)

## Connections

## Related 6

- [Cannot intubate, cannot oxygenate: front-of-neck access](https://durgical.com/en/anaesthesia/cannot-intubate-cannot-oxygenate-front-of-neck-access/)
- [Predicting a difficult airway: Mallampati, mouth opening, neck and jaw](https://durgical.com/en/anaesthesia/predicting-a-difficult-airway-mallampati-mouth-opening-neck-and-jaw/)
- [Videolaryngoscopy, bougies and other adjuncts](https://durgical.com/en/anaesthesia/videolaryngoscopy-bougies-and-other-adjuncts/)
- [Preoxygenation and apnoeic oxygenation](https://durgical.com/en/anaesthesia/preoxygenation-and-apnoeic-oxygenation/)
- [Tracheal intubation](https://durgical.com/en/anaesthesia/tracheal-intubation/)
- [Extubation: when and how](https://durgical.com/en/anaesthesia/extubation-when-and-how/)

## Related conditions 4

- [Obesity](https://durgical.com/en/conditions/obesity/)
- [Obstructive sleep apnoea](https://durgical.com/en/conditions/obstructive-sleep-apnoea/)
- [Deep neck infection and Ludwig angina](https://durgical.com/en/conditions/deep-neck-infection-and-ludwig-angina/)
- [Head and neck squamous cell carcinoma (oral cavity and oropharynx, HPV)](https://durgical.com/en/conditions/head-and-neck-squamous-cell-carcinoma/)

## In Pharmacology 3

- [Neuromuscular blockers](https://durgical.com/en/pharmacology/classes/neuromuscular-blockers/)
- [Rocuronium](https://durgical.com/en/pharmacology/rocuronium/)
- [Sugammadex](https://durgical.com/en/pharmacology/sugammadex/)

[← All of anaesthesia](https://durgical.com/en/anaesthesia/)

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: [Difficult Airway](https://www.ncbi.nlm.nih.gov/books/NBK470224/) (StatPearls (NCBI Bookshelf), 2026); [Video Laryngoscopy](https://www.ncbi.nlm.nih.gov/books/NBK623720/) (StatPearls (NCBI Bookshelf), 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/anaesthesia/the-unanticipated-difficult-airway-plans-a-to-d/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anaesthesia/the-unanticipated-difficult-airway-plans-a-to-d/