Airway management in rural ED, RSI, difficult airway, surgical airway

Overview

• Airway management failure accounts for 8-15% of potentially preventable trauma deaths.
• In the rural and remote Australian context, the stakes are amplified: specialist backup is often hours away, retrieval may be delayed, and the rural generalist must execute a full spectrum of interventions, from basic manoeuvres to surgical cricothyrotomy, with limited personnel and equipment.

Core principles:

• Oxygenation is always the primary goal.
• Not every patient requires intubation; basic manoeuvres or supraglottic devices may suffice until a more controlled environment is available.
• Every emergency airway must be assumed potentially difficult; every management plan must include a plan for failure.
• A definitive airway = a cuffed device placed in the trachea below the vocal cords (cuffed ETT or surgical airway).
• Intubation (outside cardiac arrest) is performed as modified RSI, the terms RSI and modified RSI are used interchangeably.

Indications for Airway Intervention

Timing of RSI, Factors to Consider

A functioning prehospital supraglottic airway providing adequate oxygenation may be continued, with replacement deferred until optimal personnel and equipment are available.

Assessment

Anatomical Predictors of Difficult Airway

• A reassuring assessment does not exclude difficult airway.
• Always prepare for failure.

Physiological Predictors of Peri-intubation Risk

• Hypotension: Sedative agents and positive-pressure ventilation reduce preload and can precipitate cardiovascular collapse, fluid resuscitate before RSI; prepare vasopressors.
• Hypoxia: Reduced reserve in obese, pregnant, paediatric, and patients with pre-existing lung disease, maximise preoxygenation.
• Raised ICP: In TBI, laryngoscopy without adequate sedation raises BP and ICP; apnoea causes hypercapnia and further ICP elevation.
• Hyperkalaemia risk with suxamethonium: Contraindicated > 24 hours after extensive burns, prolonged immobilisation, or spinal cord injury.

Investigations

Capnography is the gold standard for ETT confirmation: clinical signs alone (chest rise, air entry, SpO₂) are insufficient and unreliable.

Management

Airway Intervention Spectrum

Escalate stepwise unless immediate advanced airway is mandated:

1. Basic manoeuvres: chin lift, jaw thrust; allow spontaneous positioning if patient is oxygenating (especially trauma/airway injury patients)
2. Adjuncts: oropharyngeal airway (OPA), nasopharyngeal airway (NPA, avoid if base-of-skull fracture suspected), wide-bore suction
3. Supraglottic airway: LMA / i-gel as bridge, temporising, or rescue device
4. Tracheal intubation via modified RSI
5. Surgical airway: when above measures fail or are contraindicated

Modified RSI

Pre-RSI Preparation Checklist

Use a structured checklist before every RSI. Key elements:

Preoxygenation and Apnoeic Oxygenation

• High-flow O₂ via non-rebreather mask (15 L/min) for ≥ 3 minutes; or 8 vital capacity breaths where time is critical.
• In the obtunded patient, assisted BVM ventilation may be required.
• Apnoeic oxygenation: nasal cannulae at 15 L/min maintained throughout laryngoscopy, significantly extends safe apnoea time, particularly important in obese patients, children, and pregnant patients who desaturate rapidly.

RSI Medications

$$\text{Rocuronium RSI dose} = 1.2 \; \text{mg/kg}$$

Vasopressors (prepared before induction, not a substitute for volume):

• All sedative agents can cause or worsen haemodynamic derangement, doses are reduced compared to elective intubation.
• Fluid resuscitation precedes RSI in haemodynamically unstable patients; vasopressors treat vasodilation from sedatives, not shock itself.

Sugammadex

• If rocuronium is used and surgical airway is not feasible, sugammadex 16 mg/kg IV can reverse profound neuromuscular blockade. However, this is not a routine rescue strategy, waking a trauma patient is rarely a viable option.
• Stock sugammadex in rural EDs where rocuronium is used.

Laryngoscopy

• Approximately 60 seconds after NMBD administration, attempt laryngoscopy.
• Video laryngoscopy (VL) is preferred for trauma intubations, superior first-pass success rates. Standard-geometry VL blades (similar to Macintosh) are appropriate for less experienced operators. Extended-angle blades require additional training.
• Direct laryngoscopy (DL) with Macintosh blade: standard fallback for all rural generalists.
• Bougie (gum-elastic bougie / Eschmann introducer): use early when view is suboptimal; angled tip facilitates anterior passage; railroad ETT over bougie.
• BURP manoeuvre: backward, upward, rightward pressure on larynx by assistant improves laryngoscopic view; also termed external laryngeal manipulation.
• C-spine: MILS by dedicated assistant; remove anterior portion of cervical collar while maintaining MILS.
• If first attempt fails: change something (position, equipment, operator, removal of obstructing material), identical repeated attempts are unlikely to succeed.

Attempt Limits and Escalation

• Maximum 3 laryngoscopy attempts per operator; one further attempt by a more experienced operator is permitted.
• BVM or LMA ventilation is performed between every attempt, do not allow progressive desaturation.
• Every attempt risks progressive oedema and airway injury, fewer attempts are often better.

Confirmation of ETT Placement

• Mandatory primary confirmation: sustained EtCO₂ waveform present for ≥ 7 breaths.
• Secondary: bilateral air entry, symmetric chest rise, SpO₂ trend improvement.
• Visualisation of tube passing through cords is unreliable alone.
• Oesophageal intubation = absent sustained EtCO₂ → remove tube immediately → ventilate via BVM/LMA → do not reattempt until SpO₂ improved.
• Document ETT depth at teeth/gums; secure tube; reassess after every patient movement.

Difficult Airway Algorithm

PREOXYGENATION + APNOEIC OXYGENATION
 ↓
TRACHEAL INTUBATION ATTEMPTS (max 3; change technique/operator each attempt)
 ↓ FAIL → Declare "Failed Intubation"
RESCUE AIRWAY: LMA or BVM (max 3 attempts at each; switch if unsuccessful)
 ↓ FAIL → Declare "Cannot Intubate, Cannot Oxygenate (CICO)"
SURGICAL AIRWAY: Scalpel-Bougie-Tube

Surgical Airway, Emergency Cricothyrotomy

• Indication: CICO situation, failure of tracheal intubation AND supraglottic/BVM rescue.
• Once initiated, persist and secure the airway regardless of challenges encountered.

Preferred technique: Scalpel-Bougie-Tube

$$\text{Once committed to surgical airway, persist. Do not abandon the procedure.}$$

• Rural requirement: Every rural ED must have a pre-packed surgical airway kit (scalpel, tracheal hook, bougie, 6.0 mm cuffed ETT, syringe, tape/securing device).
• Rehearse this procedure in simulation at least annually.

Post-Intubation Management

Use a structured post-intubation checklist:

DOPE mnemonic: causes of post-intubation deterioration:

• D: Displacement (ETT right mainstem or dislodgement)
• O: Obstruction (mucous plug, kink)
• P: Pneumothorax (tension, from positive-pressure ventilation)
• E: Equipment failure (disconnect from ventilator → manual ventilation)

Special Populations

Traumatic Brain Injury (TBI)

• Prevent secondary injury: avoid hypotension, hypoxia, and hypercapnia.
• Laryngoscopy without adequate sedation raises BP and ICP, ensure adequate induction agent dose.
• Apnoea causes hypercapnia and raises ICP, minimise apnoea time.
• Post-intubation: target normocapnia (EtCO₂ 35-40 mmHg); MAP > 80 mmHg; SpO₂ ≥ 95%.
• Ketamine: historical concerns about ICP elevation are not supported by current evidence; remains a reasonable choice especially when haemodynamic instability coexists.

Paediatric Patients

• All airway structures proportionally smaller, use age-appropriate equipment.
• Larger occiput: place shoulder roll (not pillow) to achieve neutral alignment.
• Miller (straight) blade preferred in infants.
• Cuffed ETTs are appropriate for emergency trauma intubations in all age groups, including small children.
• Rapid desaturation due to low FRC, preoxygenation and apnoeic oxygenation are critical.

$$\text{Cuffed ETT internal diameter (mm)} = \frac{\text{age (years)}}{4} + 3.5$$

$$\text{ETT insertion depth at lips (cm)} = \frac{\text{age (years)}}{2} + 12$$

Obstetric Patients

• Reduced FRC (elevated diaphragm), increased aspiration risk (reflux, reduced lower oesophageal sphincter tone), airway oedema.
• Physiological challenges similar to obese patients.
• Left lateral tilt after 20 weeks to relieve aortocaval compression.
• Early RFDS/retrieval involvement.

Elderly Patients

• Reduced protective airway reflexes, high aspiration risk; act decisively.
• Arthritis restricts mouth opening and neck mobility, may worsen with cervical collar.
• Dentures: remove for intubation; leave in place during BVM ventilation to maintain mask seal; if removed, pack gauze between gums and cheek.
• Absence of teeth simplifies intubation but complicates BVM ventilation.
• Reduce RSI sedative doses by 20-40% (barbiturates, benzodiazepines, other sedatives) to reduce cardiovascular depression.
• Vasopressors must be prepared, hypotension after RSI is common due to physiology and pre-existing medications.

Obese Patients

• Increased tissue mass challenges every technique: mask ventilation, LMA insertion, intubation, and surgical airway.
• Head-up positioning is beneficial; insert OPA/NPA early.
• Hypoxia occurs more rapidly due to higher rates of pre-existing pulmonary disease, lower respiratory compliance, and reduced FRC.
• Apply higher PEEP post-intubation; medication dose modifications may be required.

Airway Burns

Urgent intubation is generally indicated in the presence of:

• Decreased level of consciousness
• Dyspnoea or stridor
• Decreased SpO₂
• Suprasternal, substernal, or subcostal retraction
• Full-thickness facial burns
• Oedema of oral structures or tongue
• If signs are absent, continue frequent reassessment, progressive oedema can cause obstruction.
• Airway management becomes significantly more difficult once obstruction develops.
• Early intubation may preempt obstruction; consult burns centre via telehealth when time allows.

Direct Airway Trauma

• Patients often spontaneously assume a position of breathing comfort, allow this if oxygenation is adequate; do not force supine positioning.
• Minimise instrumentation; invasive manoeuvres performed as gently as possible.
• Surgical airway equipment must be immediately available.
• Awake tracheostomy by a qualified surgeon is the safest option when available, this resource is often not available in the rural/remote context.
• A multidisciplinary approach prevents exacerbating injury.

Transfer and Retrieval Decisions

• Pre-retrieval requirements: The airway must be definitively secured before transport.
• Intubation in a fixed-wing aircraft is extremely hazardous and should be avoided.
• Confirm ETT position with CXR before departure.
• Ensure adequate post-intubation sedation and neuromuscular blockade (if required) are established and ongoing supplies are available for transport duration.

Key Rural Practice Points