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Difficult Airway Society (DAS) 2025 Guidelines: Comprehensive Stepwise Overview

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OVERARCHING PHILOSOPHY: A PARADIGM SHIFT

• 2015 focus: Managing failure - what to do when things go wrong
• 2025 focus: Optimising success - maximising chances of first-attempt success while remaining prepared for failure
• The framework (Plans A-D) is retained, but the philosophy has changed
• Emphasis on: continuous oxygen delivery, waveform capnography confirmation, multidisciplinary teamwork, and early recognition of failure

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STEP 1: AIRWAY ASSESSMENT AND PLANNING

Pre-procedural Assessment

• Conduct a structured, multimodal airway assessment before every induction
• Assess for difficulty in ALL four domains:
  • A - Tracheal intubation
  • B - SAD insertion or ventilation
  • C - Facemask ventilation
  • D - Emergency front-of-neck airway (eFONA)
• If difficulty is anticipated in any of Plans A-D, consider awake tracheal intubation (ATI)
• Airway management strategy must be guided by any history of previous difficulty

Clinical Predictors of Difficult Airway

• Reduced mouth opening, restricted neck mobility, obesity, large tongue, facial hair
• Reduced thyromental / sternomental distance
• Mallampati class III/IV
• History of previous difficult airway
• Radiation to neck, masses, trauma, anatomical distortion

Point-of-Care Ultrasound (POCUS) - New in 2025

• POCUS is now endorsed as part of pre-procedural assessment
• Applications:
  • Identify and mark the cricothyroid membrane (CTM) before induction
  • Gastric ultrasound - assess gastric content/volume to guide aspiration risk and RSI decisions
  • Confirm tracheal tube placement
  • Assess soft tissue structures of the neck
• POCUS for CTM identification should be performed in obese patients and those with difficult anatomy before induction

Planning and Communication

• The airway management strategy must be clearly communicated with the anaesthetic assistant
• Airway management discussed as part of the theatre team briefing (checklist use endorsed)
• Equipment for Plans A-D must be immediately available in all areas where airway management is performed
• Optimal location for airway management should be considered
• Out-of-hours airway management carries increased risk - plan accordingly
• Cognitive aids/checklists improve guideline adherence, reduce omissions, and optimise teamworking

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STEP 2: PATIENT POSITIONING

• Optimise patient position before preoxygenation and tracheal intubation
• Ramped/head-elevated position (external auditory meatus level with sternal notch):
  • Preferred for obese patients
  • Improves laryngoscopic view
  • Increases time to desaturation (functional residual capacity)
• Head-up position (20-30 degrees) improves preoxygenation efficiency

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STEP 3: PREOXYGENATION (PEROXYGENATION)

Goals

• Achieve maximal alveolar oxygen stores before induction
• Denitrogenate the lungs - replace nitrogen with oxygen to maximise apnoeic oxygenation time
• Target: end-tidal O2 > 87% (EtO2 >0.87) or SpO2 ≥ 98% as a surrogate

Techniques

• Tight-fitting facemask with high-flow oxygen (15 L/min) for minimum 3 minutes of tidal breathing, OR
• Eight maximal vital capacity breaths over 60 seconds with 100% O2 at high flow
• High-Flow Nasal Oxygen (HFNO):
  • Now a core recommendation - not just rescue
  • Can be used before and throughout induction and intubation attempts
  • Provides apnoeic oxygenation via diffusion
  • Rates typically 30-70 L/min
  • Extends the safe apnoea time significantly
  • Strongly recommended in: obese patients, physiologically difficult airway, anticipated difficult intubation

Special Populations

• Obese patients: HFNO for preoxygenation explicitly recommended; ramp position; earlier SpO2 targets
• Patients with reduced FRC (pregnant, obese, critically ill) desaturate much faster - maximise preoxygenation time

Continuous Oxygenation Throughout Airway Management

• A major 2025 emphasis: Oxygen should be delivered throughout ALL phases - not just preoxygenation
• Methods during laryngoscopy:
  • Nasal cannula at 15 L/min (apnoeic oxygenation)
  • HFNO continued during intubation attempts
• If SpO2 falls during any intubation attempt - abandon the attempt immediately and oxygenate first

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STEP 4: PLAN A - TRACHEAL INTUBATION

Core Philosophy

• Plan A is about deliberate, optimised first-attempt success - not multiple tries
• Maximum 3 + 1 attempts rule:
  • Up to 3 attempts by the primary operator
  • 1 additional attempt by a second experienced operator
  • Total = maximum 4 laryngoscopy attempts before declaring failed intubation

Laryngoscopy - Video Laryngoscopy as Default

• Video laryngoscopy (VL) is now the default - not the backup
• VL improves glottic view and first-attempt success rates vs. direct laryngoscopy (DL)
• DL remains acceptable when VL is unavailable or operator preference
• Have both VL and DL available

Optimisation Strategies During Plan A

• Change laryngoscope type (DL to VL, or change blade)
• Use or change an introducer (bougie/stylet)
• Change operator
• Apply external laryngeal manipulation (ELM) / BURP manoeuvre
• Suction the airway
• Remove cricoid force if applied
• Optimise neuromuscular blockade (deepen if insufficient)
• Reposition patient

Intubation Technique

• Pre-intubation checklist: STOP, THINK, POSITION, EQUIPMENT
• Maintain optimal head and neck position throughout
• Use waveform capnography to confirm placement - this is mandatory
• Capnography confirmation is the gold standard - clinical signs alone are insufficient
• Consider bougie-assisted intubation as routine, especially in difficult views

Declared Failed Intubation

• After 3+1 attempts, declare "Failed Intubation" clearly and aloud
• Move immediately to Plan B
• Summon appropriate assistance
• Prime eFONA kit (make it immediately accessible) at this point

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STEP 5: PLAN B - SUPRAGLOTTIC AIRWAY DEVICE (SAD) VENTILATION

Philosophy Change from 2015

• In 2015, Plan B meant "pause, oxygenate, consider waking the patient"
• In 2025, Plan B is not a symbol of failure - it is a strategic tool for oxygenation and decision-making
• Some patients cannot be woken up (haemodynamically unstable, full stomach, critical illness) - acknowledged explicitly

SAD Insertion and Use

• Insert appropriate SAD:
  • 2nd-generation SADs preferred (e.g. LMA ProSeal, i-gel, LMA Supreme) - provide better seal, have gastric ports
  • Size based on manufacturer recommendations and patient weight/anatomy
• Confirm SAD position with waveform capnography
• Assess ventilation quality: chest rise, bilateral breath sounds, EtCO2 trace
• Maximum 3 attempts at SAD insertion

SAD as a Bridge

• Oxygenate the patient via SAD
• Reassess the situation:
  • Can the patient be woken up? If yes, consider awakening
  • If the patient cannot be woken up, maintain oxygenation and progress
  • SAD may be used as a conduit for fibreoptic-guided tracheal intubation if expertise and equipment are available

Priming eFONA

• After declared failure at tracheal intubation, the eFONA kit should be immediately accessible
• After maximum 3 SAD attempts, the assistant should open the eFONA kit
• Clearly declare who is the most appropriately skilled individual to perform eFONA

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STEP 6: PLAN C - FACEMASK VENTILATION (FMV)

When to Use

• If SAD insertion/ventilation fails
• Acts as a final oxygenation bridge before eFONA

Technique Optimisation

• Two-person technique preferred (one person maintaining seal, second bagging)
• Oral ± nasal airway adjuncts
• Head-tilt chin-lift / jaw thrust
• Adequate seal with appropriate-sized mask
• Confirm with waveform capnography

Critical Decision Point

• Plan C represents a "stop and think" moment - but ONLY if oxygenation is clearly maintained
• If oxygenation is failing or cannot be sustained:
  • Recognise "Cannot Intubate, Cannot Oxygenate (CICO)" immediately
  • Rapid progression to Plan D is mandatory
• The 2025 guidelines explicitly state: "Rapid progression to Plan D might be necessary"
• Do NOT delay Plan D for repeated futile FMV attempts

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STEP 7: PLAN D - EMERGENCY FRONT-OF-NECK AIRWAY (eFONA)

When to Proceed

• Cannot Intubate, Cannot Oxygenate (CICO) situation declared
• This is a life-saving, time-critical intervention
• No hesitation - decisiveness is critical

Technique: Scalpel-Bougie-Tube (Recommended)

1. Stand on patient's left side (if right-handed); reverse if left-handed
2. Maximally extend the neck
3. Identify laryngeal anatomy with non-dominant hand - locate midline and cricothyroid membrane (CTM)
4. Apply tension to skin and stabilise the larynx with non-dominant hand
5. Make a vertical skin incision (top to bottom, 3-4 cm) through the skin overlying the CTM with scalpel (size 10 blade)
6. Apply caudal traction on the lower skin flap to expose CTM
7. Make a horizontal stab incision through the inferior third of the CTM
8. Dilate the incision with a tracheal hook or finger
9. Insert a bougie into the trachea, directing caudally
10. Railroad a size 6.0 cuffed tracheal tube over the bougie
11. Remove bougie, inflate cuff
12. Confirm position with waveform capnography
13. Secure tube

Key Updates for eFONA in 2025

• Vertical incision is now unambiguously recommended (debate about horizontal vs. vertical resolved)
• More than one attempt may be required - this is acknowledged and normalised
• Alternative scalpel-bougie-tube techniques are also acceptable (see DAS Supplementary File 5)
• Fundamental principles:
  • Scalpel in dominant hand
  • Incisions made away from the non-dominant hand
• Priming (preparing the eFONA kit in parallel to Plans A-C) is now a formal concept
• Oxygen delivery must be maintained throughout (via SAD, facemask, or nasal cannula)

Required Equipment for eFONA

• Scalpel with number 10 blade
• Bougie
• Size 6.0 cuffed tracheal tube
• Suction (likely needed)

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RAPID SEQUENCE INDUCTION AND INTUBATION (RSII)

Indications

• Patients at increased risk of pulmonary aspiration (full stomach, GORD, pregnancy, bowel obstruction, emergency surgery)

Key Principles

• Same general airway management principles apply
• Specific RSI considerations:
  • These patients may also have a physiologically difficult airway - assess and manage accordingly
  • Pre-oxygenate optimally (HFNO recommended when feasible)
  • Modified RSI: Gentle positive pressure ventilation is acceptable if needed to maintain oxygenation before intubation (debated but mentioned)
  • Cricoid pressure: controversial - apply only if deemed beneficial; remove if it worsens laryngoscopic view
  • Immediate Plan B (SAD) strategy should be pre-planned
  • Awake tracheal intubation (ATI) should be considered if difficulty is anticipated

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PHYSIOLOGICALLY DIFFICULT AIRWAY

Definition

Key Physiological Parameters

• Haemodynamic instability: hypotension, shock states
• Hypoxaemia: pre-existing low SpO2 (especially SpO2 < 90%)
• Acidosis/metabolic derangement
• Severe right heart failure (risk of arrest with PEEP/positive pressure)
• Tension physiology (tamponade, pneumothorax)

Management Strategies

• Pre-intubation resuscitation where possible - "resuscitate before you intubate"
• Optimise haemodynamics before induction (vasopressors, fluids, blood products)
• Ketamine preferred induction agent in haemodynamically unstable patients
• Consider awake tracheal intubation in severely compromised patients
• Use lowest effective induction doses
• Plan for post-intubation hypotension - have vasopressors drawn up
• The "wake the patient up" option is often not available in physiologically difficult airways - acknowledge this and have a clear continuation plan

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OBESITY AND AIRWAY MANAGEMENT

Specific Risks

• Increased difficulty with:
  • Facemask ventilation
  • SAD insertion and seal
  • Tracheal intubation (reduced neck mobility, excess tissue)
  • eFONA (excess adiposity obscures CTM)
• Higher basal metabolic rate = faster O2 consumption
• Reduced functional residual capacity = rapid desaturation after induction
• Increased aspiration risk

Recommended Strategies

• HFNO for preoxygenation - explicitly recommended
• Ramp/head-elevated position
• Consider awake tracheal intubation (ATI) if difficulty anticipated
• Early use of SAD if intubation fails
• POCUS for CTM identification before induction
• Refer to SOBA (Society for Obesity and Bariatric Anaesthesia) guidelines for detailed management
• Be aware that eFONA is more technically challenging - prepare accordingly

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POSTINTUBATION CARE

• Confirm tracheal tube position immediately with waveform capnography - mandatory
• Confirm and document tube depth and bilateral breath sounds
• Secure tube reliably (tape or tie)
• Consider chest X-ray to confirm placement
• Ongoing monitoring: EtCO2, SpO2, airway pressures
• Maintain oxygenation - adjust FiO2 to target SpO2 94-98% (or 88-92% in COPD)
• Set appropriate PEEP and tidal volumes
• Perform a post-procedure airway debrief
• Document clearly:
  • Number of attempts
  • Techniques used
  • Equipment used
  • Any complications
  • Grade of laryngoscopic view (Cormack-Lehane)

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DOCUMENTATION

• Documentation is a formal recommendation in 2025 (explicit section)
• Must record:
  • Airway assessment findings
  • Techniques and equipment used
  • Number of intubation attempts
  • Grade of laryngoscopic view
  • Any difficulties encountered
  • SAD type and size if used
  • Confirmation method
  • Any complications
• Alert documentation should be placed in patient records so future clinicians are forewarned
• Consider airway alert card for patients with difficult airways
• Report significant events through incident reporting systems (e.g., NAP registry)

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HUMAN FACTORS

Key Principles - New Dedicated Section in 2025

• Human factors contribute to a large proportion of airway complications
• Situational awareness: continuous monitoring of patient status, equipment, team
• Cognitive load: use checklists to reduce task omissions and mental burden
• Communication:
  • Clear, closed-loop communication with the team
  • Explicitly state plan transitions ("We are now moving to Plan B")
  • Summon help early - do not wait for crisis
• Leadership and followership: clear role assignment, shared mental models
• Fixation errors: recognise when you are fixating on one technique; know when to stop
• Stress and performance: high-stress situations degrade performance - use structured approaches
• Decision-making under uncertainty: use pre-agreed thresholds (e.g. "If I can't intubate in 3 attempts, I move to Plan B")
• Debriefing: post-event debriefs improve team learning and future performance
• Checklists and cognitive aids improve guideline adherence and teamworking

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EDUCATION AND TRAINING

• Ongoing education in airway management is a formal recommendation
• All practitioners performing airway management should maintain competence in:
  • Direct laryngoscopy
  • Video laryngoscopy
  • SAD insertion (2nd generation)
  • Facemask ventilation
  • Recognition of CICO
  • eFONA (scalpel-bougie-tube technique)
• Simulation training strongly recommended - especially for eFONA (rarely performed in real life)
• Team training including human factors components
• Practitioners should train in one eFONA technique and know it thoroughly rather than multiple techniques incompletely
• Regular competency reassessment
• DAS 2025 Guidelines Education Package available (see das.uk.com)

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SUMMARY: THE LINEAR ALGORITHM AT A GLANCE

AIRWAY ASSESSMENT + PLANNING
        ↓
   PREOXYGENATION / PEROXYGENATION
   (HFNO + Nasal cannula throughout)
        ↓
 PLAN A: TRACHEAL INTUBATION
 (VL as default, max 3+1 attempts)
 Optimise: blade/VL, bougie, operator,
 ELM, position, NMB, suction
        ↓ FAILED (declare aloud) + prime eFONA
 PLAN B: SAD VENTILATION
 (2nd gen SAD, max 3 attempts)
 Oxygenate → consider waking / continue
        ↓ FAILED + open eFONA kit
 PLAN C: FACEMASK VENTILATION
 (Two-person, adjuncts, waveform cap)
        ↓ CICO declared
 PLAN D: eFONA
 (Scalpel no.10 + bougie + size 6.0 ETT)
 VERTICAL skin incision → stab CTM
 → bougie → tube → capnography confirm

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KEY CHANGES FROM DAS 2015 TO DAS 2025

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PRIMING: A NEW CONCEPT IN 2025

• Priming is the process of preparing for eFONA in parallel to Plans A-C
• It ensures equipment is immediately available and appropriate staff are present and cognitively prepared
• Timeline:
  • After declared failed intubation (Plan A): eFONA kit made immediately accessible; declare who will perform eFONA
  • After maximum 3 SAD attempts (Plan B/C failure): assistant opens the eFONA kit
• This is not a passive process - it requires active preparation and communication

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AWAKE TRACHEAL INTUBATION (ATI) - WHEN TO CONSIDER

• Anticipated difficulty in any of Plans A-D
• Significant physiological compromise where failed intubation cannot be tolerated
• Morbid obesity with difficult airway predictors
• Restricted mouth opening (trismus, angioedema, mass lesion)
• Unstable cervical spine
• History of previous failed intubation
• When "cannot wake the patient" is foreseeable
• Technique requires preparation: topicalisation, vasoconstriction, sedation with airway-safe agents, patient cooperation

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