---

All India Difficult Airway Association (AIDAA) 2025 Guidelines

Comprehensive Notes for MD Anaesthesiology Exam

---

1. BACKGROUND AND OVERVIEW

• Unanticipated difficult airway in adults under GA
• Unanticipated difficult airway in obstetrics under GA
• Unanticipated difficult airway in paediatrics (1-12 years) under GA
• Management of at-risk extubations

• Systematic literature review + three-round Delphi process among Indian and international airway experts
• Evidence graded using Class of Recommendation and Level of Evidence
• Where evidence was absent or weak, expert consensus statements were generated

---

2. KEY DIFFERENCES FROM AIDAA 2016 GUIDELINES

---

3. FUNDAMENTAL CONCEPTS (AIDAA TERMINOLOGY)

A. Complete Ventilation Failure (CVF) - AIDAA's Unique Term

Key Point for Exam: CVF is the trigger for emergency cricothyroidotomy - NOT hypoxaemia or SpO2 fall. Ventilation failure precedes oxygenation failure, so acting at CVF while SpO2 is still maintained gives you a safer window to act.

B. Code D

• Activated when the primary airway plan fails
• Calls for additional help from senior/experienced personnel
• Introduced newly in AIDAA 2025 (not in 2016)

---

4. AIRWAY ASSESSMENT - AIDAA 2025

Anatomical Difficult Airway Predictors

• Standard predictors (Mallampati, TMD, IIG, neck extension, etc.) still apply
• POCUS now endorsed to identify:
  • Tongue thickness
  • Skin-to-trachea distance (anterior airway)
  • Subglottic narrowing
  • Distorted anatomy from previous surgery/radiation/obesity

Physiologically Difficult Airway (New in 2025)

• Formally recognized category for the critically ill patient
• Includes: severe hypoxaemia, haemodynamic instability (shock), metabolic acidosis, obesity with reduced FRC
• These patients cannot tolerate apnoea - require aggressive pre-oxygenation and optimisation before intubation
• "Wake-up and try again" is NOT always an option in physiologically difficult airways

---

5. THE AIDAA 2025 ALGORITHM - ADULTS

Pre-intubation Phase

• Pre-oxygenation: Aim for SpO2 = 100% (minimum >95%) before any attempt
• Apnoeic oxygenation: Nasal oxygen 10-15 L/min via nasal catheter/cannula throughout all phases
• High-Flow Nasal Oxygen (HFNO) is an option and increases safe apnoea time
• Oxygen delivery should be continuous and never interrupted

• Proceed with the next attempt at laryngoscopy only if SpO2 ≥ 95%
• This rule applies throughout the algorithm

• Complete NMB should be ensured before declaring complete ventilation failure
• A final attempt at ventilation after ensuring full NMB is mandatory before declaring CVF

---

Primary Airway Plan

• Direct laryngoscopy is still acceptable but VL maximises first-attempt success
• Confirmation of TT placement: 6 consecutive sustained waveform capnography traces (AIDAA's specific criterion, introduced in 2016, retained in 2025)
• If primary plan succeeds → proceed with anaesthesia

---

Airway Rescue Phase (Circular Algorithm)

• Maximum: 3 attempts total (including the primary attempt)
• Each attempt must be by the most experienced available operator
• Optimise position, use stylet/bougie, consider different laryngoscope blade
• Maintain nasal oxygenation between attempts

• Maximum: 3 attempts for SGA insertion
• 2nd generation SGAs (e.g., ProSeal LMA, i-gel, Supreme LMA) preferred over 1st generation
• Can be used for:
  • Rescue oxygenation
  • Conduit for fibreoptic-guided intubation
  • Maintaining anaesthesia if SpO2 is adequate
• Confirmation: adequate chest rise + capnography trace

• Maximum: 3 attempts for FM ventilation
• Two-person mask ventilation with adjuncts (oropharyngeal/nasopharyngeal airways)
• Optimal head-tilt chin-lift / jaw thrust positioning

Key: In the circular design, there is NO fixed order between TT, SGA, and FM. Move to whichever device is most likely to succeed based on the clinical situation. Keep SpO2 ≥ 95% throughout.

---

Decision Point After Rescue

• Consider: wake the patient up and reassess OR
• Continue anaesthesia (if surgery is immediately life-saving) with a secured airway
• Plan must be discussed with the team

---

Complete Ventilation Failure (CVF) → Emergency Cricothyroidotomy

1. Declare Complete Ventilation Failure
2. Call for additional help (Code D remains active)
3. Maintain nasal oxygenation throughout
4. Proceed immediately to Emergency Surgical Cricothyroidotomy

• Stab incision through cricothyroid membrane
• Bougie passed into trachea
• Size 6 tracheal tube railroaded over bougie
• Rationale: universally available equipment, can be done rapidly

---

6. AIDAA 2025 - OBSTETRIC GUIDELINES (Key Points)

• Same circular algorithm with Code D and CVF framework
• Additional unique triggers:
  • If maternal cardiac arrest occurs during airway crisis → proceed to resuscitative hysterotomy to improve chances of saving both mother and baby
• Videolaryngoscopy recommended as first-line in obstetric patients
• Rapid Sequence Induction (RSI) with cricoid pressure remains standard for GA in obstetrics
• Consider awake intubation for anticipated difficult airway in parturients when time permits
• Post-resuscitation care in ICU with team debriefing mandated

---

7. AIDAA 2025 - PAEDIATRIC GUIDELINES (1-12 Years)

• Same circular design with device interchangeability
• Maximum intubation attempts: 2 failed attempts + 3rd attempt only by a paediatric airway expert
• "Code D" applies here too
• Emergency airway access differs from adults:
  • Surgical cricothyroidotomy is CONTRAINDICATED in children < 12 years (risk of fracture of laryngeal cartilages, cricothyroid membrane too small)
  • Children < 5 years: Needle cricotracheal puncture (< 4mm needle) + jet ventilation
  • Children 5-12 years: Needle cricothyroid puncture + jet ventilation
  • When trained surgical help available: Scalpel-bougie tracheostomy preferred
  • Pressure-regulated jet ventilation device recommended

---

8. PERI-INTUBATION OXYGENATION - SUMMARY TABLE

---

9. WAVEFORM CAPNOGRAPHY - AIDAA SPECIFIC CRITERION

Six consecutive, sustained waveform capnography traces without a fall in CO2 levels

• This is AIDAA's specific (and stricter) criterion compared to other guidelines
• Introduced in 2016, retained in 2025
• SpO2 alone is insufficient; colorimetric CO2 detectors are inferior
• Reason: Prevents false reassurance from initial CO2 traces in oesophageal intubation

---

10. HUMAN FACTORS (New Emphasis in 2025)

• Shared mental models and clear communication
• Designated team leader
• Role assignment before intubation (who hands instruments, who preps cricothyroid membrane, who manages drugs)
• "Stop and think" prompts built into the algorithm before each escalation
• Briefing (pre-intubation) and debriefing (post-event) mandated
• Cognitive aids / checklists recommended in the environment

---

11. DIFFICULT AIRWAY CART / KIT - "Code D" Essentials

• Videolaryngoscope
• Assorted SGAs (2nd generation preferred)
• Flexible fibreoptic bronchoscope / video bronchoscope
• Airway exchange catheters / bougies
• Equipment for surgical cricothyroidotomy: stab knife + bougie + size 6 tube
• Jet ventilation device (especially for paediatric settings)
• Waveform capnograph

---

12. DOCUMENTATION AND POST-PROCEDURE PLAN

1. Detailed documentation of airway difficulty, devices attempted, number of attempts, SpO2 nadir
2. Clear post-procedure airway management plan (e.g., who manages extubation, where patient recovers)
3. Team debriefing after every difficult airway event
4. Team support - recognising psychological impact on anaesthesia team
5. Patient and family counselling regarding the airway difficulty
6. Issuance of Airway Alert Card

---

13. RAPID SEQUENCE INDUCTION (RSI) - 2025 Updates

• Videolaryngoscopy is strongly supported as the device of choice for RSI
• Cricoid pressure: remains recommended in obstetrics and high-aspiration-risk cases
• Adequate NMB confirmed before declaring CVF
• Modified RSI (with gentle bag-mask ventilation) acceptable in patients with anticipated hypoxaemia (physiologically difficult airway)

---

14. COMPARISON: AIDAA 2025 vs AIDAA 2016 - Quick Revision

---

15. EXAM HIGH-YIELD POINTS

1. CVF = TT + SGA + FM all failed (even if SpO2 maintained) → trigger for immediate surgical cricothyroidotomy
2. Code D = hospital emergency code for difficult airway; activate when primary plan fails
3. Capnography criterion = 6 consecutive sustained waveforms to confirm TT placement
4. Algorithm is circular (not linear) - no fixed device hierarchy in rescue
5. SpO2 ≥ 95% must be maintained before each new attempt
6. Apnoeic O2 = 10-15 L/min nasal oxygen throughout
7. Surgical cricothyroidotomy = scalpel-bougie-tube = preferred in adults
8. Children < 12 yr = NO surgical cricothyroidotomy; use needle-based techniques
9. Videolaryngoscopy = first-line intubation device (not just rescue)
10. Airway Alert Card + debriefing + family counselling = mandatory post-event
11. In obstetrics: maternal cardiac arrest during airway crisis → resuscitative hysterotomy
12. AIDAA 2025 published in Indian Journal of Anaesthesia, Vol. 69, Issue 11, November 2025

---

• Myatra SN, Shah AP, Ramkumar V, et al. All India Difficult Airway Association 2025 Guidelines for the management of unanticipated difficult airway in adults under general anaesthesia. Indian J Anaesth. 2025;69:1117-1141. Available at PMC12643155
• AIDAA 2025 Obstetric Guidelines. Indian J Anaesth. 2025;69. Available at PMC12643153
• AIDAA 2025 Paediatric Guidelines. Indian J Anaesth. 2025;69. Available at PMC12643152
• Garg R, Ahmed SM, Myatra SN. Assembling a Difficult Airway Cart/Kit, declaring "Code D", and issuing an Airway Alert Card. Indian J Anaesth. 2025. PMID: 41293141