Failed Intubation: Plan B and C in the Airway Algorithm

Failed intubation is one of the most critical situations in emergency and acute care medicine. Statistically, endotracheal intubation in the emergency department or prehospital setting succeeds on the first attempt in only about 80–85% of cases – meaning a relevant proportion of patients require a structured Plan B or even Plan C. The decisive question is not whether you will ever find yourself in this situation, but whether you will then have a clear, well-practiced algorithm ready to deploy. An unstructured approach to difficult airway management costs time, and in this context, time means oxygen – and therefore your patients' lives.

The Importance of a Predefined Strategy

The most common mistake in failed intubation is not the failure of the first attempt, but the absence of a predetermined plan. Repeated, identical intubation attempts without a change in strategy – the so-called "repeated same approach" – worsens conditions with each attempt due to swelling, bleeding, and progressive hypoxia. The DAS guidelines (Difficult Airway Society) and DGAI recommendations therefore emphasize a central principle: Every intubation attempt must be the best possible one, and every subsequent attempt must involve a change in strategy.

The maximum number of intubation attempts is limited to three plus one by a more experienced person – a maximum of four laryngoscopies in total. Every attempt beyond this limit increases the complication rate exponentially: the incidence of esophageal intubation, aspiration, airway edema, and cardiovascular collapse rises dramatically with each additional attempt.

The 3-3-2 Rule and Predicting the Difficult Airway

Before the algorithm even comes into play, anticipation is crucial. Predictors of the difficult airway include:

• Mallampati score III–IV
• Thyromental distance < 6 cm (less than 3 fingerbreadths)
• Limited mouth opening < 3 cm
• Limited cervical spine mobility
• Obesity with neck circumference > 43 cm
• Facial trauma, airway bleeding, swelling
• Anatomical variations (retrognathia, short neck, protruding incisors)

Identifying these factors allows you to mentally and materially prepare Plan B and C before the first attempt. Ideally, the bougie, supraglottic airway device, and cricothyrotomy kit should be within arm's reach before the laryngoscope is even picked up.

Plan A: The Optimized First Intubation Attempt

Plan A is not just a simple attempt – it is the best first attempt. It involves optimizing all modifiable factors:

• Positioning: Improved Jackson position or ramped position for obese patients (tragus at the level of the sternum)
• Preoxygenation: At least 3 minutes with 100% O₂ via tight-fitting mask or high-flow nasal cannula (HFNC) to extend apnea tolerance
• Apneic oxygenation: Continue nasal oxygen delivery (15 L/min) during the intubation attempt
• BURP/ELM maneuver: External laryngeal manipulation (backward, upward, rightward pressure) to improve glottic visualization
• Appropriate blade selection: Consider videolaryngoscopy as first-line for anticipated difficult airways

If Plan A fails – defined as failure to intubate within 30 seconds or inability to visualize the vocal cord plane – structured escalation begins.

Plan B: Strategy Change After a Failed First Attempt

Plan B is the critical moment that separates a structured from an unstructured approach. The principle is: Change at least one variable. The options can be systematically categorized.

Bougie Technique

The bougie (Eschmann stylet or Frova introducer) is the simplest and most effective tool when glottic visualization is limited. The success rate at Cormack-Lehane grade III increases from approximately 60–70% to over 90% with bougie use.

Technique:

1. Keep the laryngoscope in position
2. Insert the bougie with the angled tip (coudé tip) directed anteriorly
3. Advance along the epiglottis – correct tracheal placement is confirmed by:
   • Click sign (tactile feedback as the tip passes over the tracheal rings)
   • Hold-up sign (resistance at approximately 30–40 cm due to encountering the main bronchus bifurcation)
4. Railroad the tube over the bougie, rotating the tube 90° counterclockwise to avoid catching on the arytenoid cartilage
5. Remove the bougie and verify tube placement

Important: A bougie should be within reach for every intubation attempt – not searched for only after failure. Many experts recommend the bougie-first approach, meaning primary use with every intubation attempt.

Switching to Videolaryngoscopy

If the first attempt was performed with direct laryngoscopy, switching to a videolaryngoscope (VL) is the logical next step. Videolaryngoscopes improve glottic visualization by an average of one to two Cormack-Lehane grades.

Different blade geometries should be considered:

• Macintosh-shaped blades (e.g., C-MAC, GlideScope): Allow both direct and indirect laryngoscopy; the intubation pathway is similar to direct laryngoscopy
• Hyperangulated blades (e.g., D-Blade, McGrath X-Blade): Better view "around the corner" but require a more pre-shaped tube or a specialized stylet; paradoxically, tube delivery despite good visualization can be more difficult

Practical tip: With a hyperangulated blade, do not advance the tube too far into the oral cavity before identifying the tip on the monitor. The most common problem is not visualization but tube passage through the glottis.

Combination: Videolaryngoscopy + Bougie

The combination of VL and bougie often represents the last successful attempt before switching to a supraglottic airway in the most difficult situations. The bougie's narrower profile and steerable tip make it easier to navigate through a difficult-to-reach glottis than a tube.

Changing the Operator

The DAS guidelines explicitly recommend: If two failed attempts by the same person have not achieved success, the most experienced available person should take over the next (and ideally last) attempt. This handover is not a sign of weakness but an active safety step.

The Critical Decision: Declaring "Can't Intubate"

After a maximum of three attempts (plus one by a more experienced person), the clear decision must be made: "Intubation failed – switch to supraglottic airway." This decision requires leadership and clear team communication.

The declaration is made loudly and unambiguously. A proven approach in team communication is:

"Intubation failed – we are switching to Plan B: supraglottic airway. Please prepare the laryngeal mask/laryngeal tube."

Plan C: Supraglottic Airway as a Rescue Strategy

The supraglottic airway (SGA) in the "Can't Intubate" situation is not a compromise but an evidence-based rescue strategy. Second-generation SGAs (with gastric drainage channel) offer advantages:

• i-gel: No cuff inflation required, rapid placement, high first-pass success rate
• LMA Supreme / LMA ProSeal: Higher sealing pressures, gastric access
• Laryngeal tube (LTS-D): Widely used in prehospital settings, easily applicable even for less experienced providers

Placement Technique and Confirmation of Success

• Size selection according to manufacturer specifications (weight or anatomical landmarks)
• Insert in the midline, inflate cuff (if applicable)
• Confirmation of placement: capnography (mandatory!), chest excursions, auscultation
• Monitor ventilation pressures: leakage at > 20 cmH₂O suggests malpositioning

Maximum two insertion attempts for the SGA. If this strategy also fails, you are in a "Can't Intubate, Can't Oxygenate" (CICO) situation.

Oxygenation via SGA as a Bridge

If oxygenation via the SGA is successful, you have bought time. The following options are now available:

• Continued ventilation via SGA as a definitive strategy (e.g., for short procedures or as a transport solution)
• Fiberoptic intubation through the SGA (using i-gel or LMA as a conduit)
• Awake fiberoptic intubation after the patient wakes up (if clinically appropriate)
• Surgical airway planned and under controlled conditions

Plan D: CICO – Can't Intubate, Can't Oxygenate

The CICO situation is the nightmare of airway management – and simultaneously the situation in which a previously practiced algorithm determines life or death. The incidence is estimated at approximately 1:50,000 in elective anesthesia but is significantly higher in emergency medicine.

Cricothyrotomy as a Lifesaving Procedure

Emergency cricothyrotomy is the only remaining route to oxygenation. The DAS guidelines recommend the surgical technique as the primary method over needle cricothyrotomy sets, as the success rate is higher and the complication rate is lower.

Scalpel-Bougie-Tube Technique (surgical cricothyrotomy):

1. Identification of the cricothyroid membrane: Palpable membrane between the thyroid and cricoid cartilage. If landmarks are not palpable: laryngeal handshake (bimanual palpation of the larynx from cranial to caudal)
2. Skin incision: Horizontal stab incision through skin and membrane with a scalpel (blade No. 10 or 20), approximately 3–4 cm
3. Stabilization: Rotate the scalpel 90° or insert a tracheal hook/finger to keep the opening patent
4. Insert bougie: Through the incision, directed caudally into the trachea
5. Tube over bougie: Advance a cuffed tube (ID 6.0) over the bougie
6. Inflate cuff, initiate ventilation, attach capnography

Time frame: From CICO declaration to the first breath via cricothyrotomy, no more than 120 seconds should elapse. This time window is realistically achievable only through regular training on manikins or cadaver specimens.

Needle Cricothyrotomy vs. Surgical Access

Needle cricothyrotomy (e.g., with a Melker kit or comparable Seldinger-based kits) has a significantly higher failure rate in stress situations. Common problems include:

• Kinking of the cannula
• Misdirected puncture (paratracheal, esophageal)
• Inadequate ventilation due to the small inner diameter
• Barotrauma with jet ventilation through narrow cannulas

For these reasons, the surgical technique is recommended as the standard procedure by DAS and DGAI. Needle-based techniques remain an alternative when no scalpel is available or in pediatric patients under 8–10 years of age (surgical cricothyrotomy is contraindicated in this age group due to anatomical considerations; needle puncture with jet ventilation is used instead).

Time Management and Oxygen Resources

A frequently underestimated aspect is time management. SpO₂ in apneic patients after adequate preoxygenation typically drops below 90% after 4–6 minutes (significantly faster in obese or critically ill patients – sometimes within 60–90 seconds).

Recommended time limits:

Phase	Maximum Duration
Single intubation attempt	30 seconds
Interim ventilation/reoxygenation	Until SpO₂ > 95%
Total intubation attempts (Plan A+B)	3+1 attempts
CICO to cricothyrotomy	< 120 seconds

Between attempts, reoxygenation must occur – either via bag-mask ventilation or nasal high-flow oxygenation. Never start the next attempt while the patient is desaturating.

Human Factors and Team Communication

Failed intubation is not only a technical problem but above all a human factors problem. Cognitive fixation on intubation (fixation error), performance pressure, and lack of role clarity within the team are the most common reasons for deviating from the algorithm.

Proven strategies:

• Briefing before intubation: "If intubation fails, Plan B is the bougie, Plan C is the laryngeal mask, Plan D is the cricothyrotomy."
• Designated timekeeper: One person on the team who exclusively monitors SpO₂ and number of attempts and communicates loudly
• 10-for-10 principle: After two failed attempts, pause for 10 seconds to reassess the situation
• Closed-loop communication: Every action is ordered, repeated, and confirmed upon completion

Declaring the CICO situation is psychologically one of the most difficult decisions. Studies show that cricothyrotomy in simulation training is regularly performed too late – often only after irreversible hypoxia has occurred. A clear, pre-agreed statement within the team lowers this threshold: "CICO – we are performing an emergency cricothyrotomy now."

Documentation and Follow-Up

After a failed intubation, structured documentation is essential:

• All devices and techniques used
• Cormack-Lehane grade at each attempt
• Duration of desaturation episodes
• Successful method
• Recommendations for future airway management

An airway alert card or corresponding documentation in the discharge letter is potentially lifesaving for the patient during future anesthetics. A team debriefing should also take place after every failed intubation – both for clinical review and for psychological support of those involved.

Practical Training

The airway algorithm for failed intubation is a prime example of a competency that can only be reliably recalled through regular practical training. Theoretical knowledge alone is not sufficient when decisions must be made in seconds under time pressure with a falling SpO₂. In the ACLS courses by Simulation Tirol, you train these scenarios on realistic simulators, practice the bougie technique, the switch to supraglottic airways, and the sequence of emergency cricothyrotomy – embedded in realistic team scenarios with structured debriefing. This transforms the algorithm on paper into an actually retrievable action pattern.