Author of this lesson-

Dr Sara Clements, FACEM

Escalation of supplemental oxygenation

• Nasal prong oxygen
  • 1-8 litres/minute (>4L should be humidified, in general,>6L move to mask)
  • FiO₂ calculation = 20% + (4x oxygen litre flow)
  • FiO₂ influenced by breath rate, tidal vol, pathophysiology and is inconsistent

• Hudson mask  
  • 5-10 litres/minute (>5L/min to washout exhaled gas/ CO₂)
  • FiO₂ 40-60%
  • Again FiO₂ influenced by breath rate, tidal vol, pathophysiology and can be inconsistent
  • NB venturi masks can deliver fixed FiO₂ – useful in CO₂ retainers

• Non-rebreathe mask (NRB)
  • 8-15 litres/minute
  • FiO₂ >40% and can delivery up to 80% if >10L

• Humidified high flow nasal prong oxygen (HHFNP)
  • 10-60 litres/minute
  • FiO₂ up to 100% when at max flow
  • Can use the blender to provide precise oxygen delivery
  • Some PEEP can be delivered (10L flow approx. 1cm/H₂0 PEEP depending on model)

• NIV – covered elsewhere
  • CPAP = continuous positive airway pressure – used APO/CCF
  • basically PEEP, splints airways, increases oxygenation, recruitment and decreases work of breathing
  • BPAP = bilevel positive airway pressure – used COPD (and asthma)
  • EPAP = expiratory positive airway pressure = PEEP
  • IPAP = inspiratory positive airway pressure = increased pressure support and tidal volumes
  • Increases oxygenation and decreases CO₂ retention
  • To increase O₂ – increase EPAP (increases peep and recruitment)
  • To decrease CO₂ – increase IPAP (increases tidal vol and ‘blow off CO₂’)
  • Settings need at least 4 cm/H₂0 between – safe starting point EPAP 4 IPAP 10

• Intubation

 

Simple airway manoeuvres & adjuncts

• Head tilt, chin lift-
• • Indication – initial airway control in an obstructed airway
  • Relative contraindication – concern of spinal injury/patient in spinal precautions

• Jaw thrust-
  • Indications – in addition to head tilt/chin lift especially in large/obese patients, jaw thrust without head tilt recommended when patient in spinal precautions
  • Contraindications – no absolute contraindication – remember airway takes priority

Figure- Chin lift, head tilt, jaw thrust.

• Bag Valve Mask ventilation +/- PEEP valve (Mapleson circuit used in some centres)

(Medscape, 2020)

• • Indications – respiratory failure, pre-oxygenation, emergency need to oxygenate/ventilate
  • Contraindications – no absolute

• • Procedure – 1 & 2 handed techniques – 2 handed technique recommended
  • ‘EC Hand position’ – thumb and index finger holding mask in a ‘C’ position – thumb superior and index inferior. 3,4,5^th finger hold mandible and perform a jaw thrust
  • Consider the use of a peep valve and/or airway adjunct to facilitate successful BVM ventilation

Figure- BVM techniques

• • Predictors of difficult bag ventilation ‘MOANS’

• • • Mask seal e.g. beards (smear with lube), blood face/mouth, facial trauma
    • Obesity/obstruction – e.g. obesity, pregnancy, angioedema, Ludwig’s angina, airway abscess
    • Age >55 years old
    • No teeth – leave dentures in the mouth with BVM, removed for ETT
    • Sleep apnoea/Stiff lungs e.g. OSA, COPD, asthma, ARDs

 

• Guedel/Oropharyngeal airway

https://youtu.be/caxUdNwjt34?si=105kj8pEhvxTLSQ0

(Amerramedical, 2018)

• •  Indications – Unconscious patient with loss of upper airway muscle tone, unconscious patient with difficult bag/mask seal and intubated patient as a bite block
  • Contraindications – Patients with cough or gag reflex – can stimulate vomiting, laryngeal spasm or aspiration. Relative contraindication – coagulopathy

 

• • Insertion
  • Gently suction blood/secretions from the mouth
  • Select correct size – the midpoint of incisors to the angle of the jaw (but other ways to measure)
  • Insert the device into mouth pointing towards the roof of the mouth
  • Once almost fully inserted, turn 180 degrees so it sits as outlined in the below picture
  • Guedel should sit flush against lips/just in front of teeth if not reinsert or resize

 

Figure- Guedel airway insertion

• Nasopharyngeal airway

(Tac Med, 2017) 

• • Indications – relief of upper airway obstruction in awake/semi-comatose/lightly anaesthetized patients. Also can be used in addition to Guedel to open airway
  • Contraindications – signs of basilar skull fractures, facial trauma, and disruption of the midface, nasopharynx or roof of the mouth are absolute contraindications

 

• • Insertion
  • Select correct size – a good rule is about the diameter of the patient’s finger and extends from tip of the nose to the earlobe
  • Lubricate the end of the nasopharyngeal airway with water-based lubricant
  • Insert slowly aiming straight back towards tragus (not upwards)
  • NP should feel snug but do not force it. If it feels stuck, remove and try the other nostril

Figure- Nasopharyngeal insertion

 

Preparing for intubation with ETT

• Indications (LITFL, 2015)
  • Airway protection and patency
  • Respiratory failure (hypercapnic or hypoxic), decreased work of breathing, secretion management / pulmonary toilet, to facilitate bronchoscopy
  • Minimise oxygen consumption and optimize oxygen delivery (e.g. sepsis)
  • Unresponsive to pain, to terminate seizure, to prevent secondary brain injury
  • Temperature control (e.g. serotonin syndrome)
  • For humanitarian reasons (e.g. procedures) and for safety during transport (e.g. psychosis)

* in adult cardiac arrests some evidence points to prioritizing oxygenation and good advanced life support over intubation – felt to be a reflection on pauses required to intubate. US study patients intubated were significantly less likely to survive to discharge and less likely to be discharged with good functional status (Angus DC et al, 2017)

• Contraindications
  • No absolute contraindications when an emergency procedure
  • If CICV or predicted difficult airway (oedema/burns) strongly consider alternatives e.g. surgical front of the neck, nasal fibreoptic etc

 

• Preparation for the procedure – USE A CHECKLIST
  • Staff – 1 doctor minimum likely more, 2-3 nursing staff minimum to assist
  • Area – Resus ED, Theatre, ICU, met calls
  • Equipment – SOAP-ME checklist
  • Drugs – sedation and paralysis

• Equipment checklist SOAP-ME

(A Pinkins, 2015)

• • Suction
  • Oxygen – Nasal cannula, non-rebreather, BVM
  • Airways – ETT – e.g. size 7 female, size 8 male, LMA, BVM, front of neck kit, airway adjuncts
  • Positioning – ‘Sniffing the morning air’. Position possibly most important step
  • Medications – Sedation e.g. propofol, ketamine and paralysis e.g. rocuronium, suxamethonium. RSI vs delayed sequence intubation
  • Equipment – laryngoscope – mackintosh/straight blade/video, EtCO₂, Bougie, stylet
• Predictors of a difficult intubation LEMON
• • Look
  • Evaluate
  • Mallampati
  • Obstruction
  • Neck mobility

 

• LOOK for external characteristics known to cause difficult laryngoscopy, intubation or ventilation
• EVALUATE 3-3-2-1

Figure- 3, 3, 2, 1

• • 3 – Ideally the distance between the patient’s incisor teeth should be at least 3 finger breadths
  • 3 – Distance between the hyoid bone and the chin should be at least 3 finger breadths
  • 2 – Distance between the thyroid notch and the floor of the mouth should be at least 2 finger breadths
  • 1 – Lower jaw should not sublux more than 1cm

• MALLAMPATI

Figure- Mallampati: The patient sits upright, opens mouth and protrudes the tongue. Grades are based on the visibility of the uvula, posterior pharynx, hard, and soft palate

• OBSTRUCTION
  •  Assess for conditions leading to an airway obstruction such as peritonsillar abscess, trauma or epiglottitis

• NECK MOBILITY
  •  Patient places chin down onto their chest and extend their neck.
  • Remove the hard collar and provide manual stabilization in trauma patients.
  • Poor neck mobility impacts ability to have airway access alignment.

Once you are all set if time permits begin with preoxygenation.

 

Preoxygenation

<iframe src=”https://player.vimeo.com/video/31312590?h=fbc2713ad4″ width=”640″ height=”480″ frameborder=”0″ allow=”autoplay; fullscreen; picture-in-picture” allowfullscreen></iframe>
<p><a href=”https://vimeo.com/31312590″>BVM with PEEP Valve and Nasal Cannula</a> from <a href=”https://vimeo.com/emcrit”>Scott from EMCrit</a> on <a href=”https://vimeo.com”>Vimeo</a>.</p>

 

(Scott from EMCRIT, 2014)

• Indications
  • The aim is to prolong the safe apnoea time
  • De-nitrogenation
  • Achieve SaO₂ as close to 100% as possible
  • With adequate oxygenation, a normal healthy person increases apnoeic time to 8 min

• Factors decreasing safe apnoea time
  • Critically unwell
  • Obesity
  • Pregnancy
  • Airway Obstruction
  • Increased oxygen consumption
  • Shunt pathology
  • Severe anaemia

• Contraindications
  • Crash intubation

• Procedure methods
  • Most commonly 15 litres nasal prong oxygen with 15 litres non-rebreathe mask
  • Alternatives depending on circumstances include
  • BVM/Mapleson c circuit +/- PEEP
  • NIV – CPAP
  • HHFNC
  • Insertion of LMA and BVM
  • In ED often the most familiar approach is the use of apnoeic 15L nasal prong oxygen plus an NRB or BVM
  • If oxygen saturations >95% and the patient has adequate respiratory drive, consider additional 15 litres non-rebreathe mask for at least 3 minutes
  • If oxygen saturations are <95% or inadequate respiratory effort then consider using gentle BVM ventilation to optimise patient and minimise desaturation before induction. (Be aware of risk gastric insufflation and aspiration risk)

 

Approach to securing a definitive airway

• Assume every airway will be difficult
• Know your plan and communicate it to your team
• Very few indications for crash intubation – if you can bag the patient you have time
• Know your difficult airway algorithm & when to use surgical airway
• Know when other approaches may be required e.g. fibreoptic/straight to the front of neck etc
• The basics are the most VIP
• Optimise patient – prepare, preoxygenation & position (covered in next section)
• Have logical escalation plan – Vortex VS Difficult airway society guidelines (DAS) – pick your favourite and know it
• Prior to being in the situation decide how you personally will manage a ‘can’t intubate, can’t ventilate’ (CICV) patient or a potentially difficult airway. Will you personally pick to do a needle cricothyroidotomy vs surgical cricothyroidotomy and why??
• Be very clear in your own mind retiming of moving to the front of neck access
• The hardest part of a surgical airway is making the decision to perform one

Vortex

• Start in the green area – preparation phase including optimising list on the right.
• Blue zone is once the patient has been induced. Make first attempt most appropriate and best attempt. If 1^st attempt doesn’t work, then move onto one of the other ‘blue’ options (sometimes known as lifelines).
• If all 3 blue options exhausted and the patient is unable to be ventilated, then move to the central dark blue area which is front of neck access and surgical airway

Figure- The Vortex

 

Difficult airway society guidelines DAS

https://vimeo.com/103516601

(The Elaine Bromiley Case, 2016)

https://youtu.be/DuLPCAM6ZhA

(openairway.org, 2016)

(Noting that in critical care situations there isn’t always the option to wake the patient up and a current ED intubation plan is likely to be video laryngoscopy as by definition higher risk)

Figure- DAS guidelines

Figure- Modified DAS

 

Laryngoscopy and ETT insertion

https://litfl.com/direct-laryngoscopy/

(LITFL, 2019)

https://emcrit.org/emcrit/rich-levitan-airway-lecture/

(EM-crit 2012)

• Indications, contraindications, staff, area, equipment, drugs all discussed previously.
  • Procedure
  • Direct laryngoscopy – use of laryngoscope to visualise the vocal cords (larynx) under direct vision Indirect using camera/CMAC

• 4 key steps
  • Positioning and preparation
  • Epiglottoscopy (identification of the epiglottis)
  • Laryngeal exposure
  • Delivery of the tube

• Step 1. Positioning and preparation
  • Operator – aim optimal visualisation/straight line of sight to glottic structures. 30-45 cm away from the target. Hold laryngoscope as low as possible on the handle, with the elbow close to the operator’s body. Hold arm somewhere between 90 degrees flexed to fully extended
  • Patient – ear to sternal notch alignment – either pillows under head or ramp bed (e.g. c spine precautions). Also improves preoxygenation and decreases aspiration risk.

Figure- Top- poor intubation posture of the operator, Bottom- Ideal posture of the operator

Figure- Proper intubation technique

• Step 2. Epiglottoscopy
  • Open the mouth as wide as possible
  • Insert laryngoscope 3-4cm into the mouth and gently sweep tongue to the left
  • Advance blade gently identifying anatomy as you go and find the epiglottis
  • Position the tip of the blade in the vallecula and lift the epiglottis

Figure- Epiglottoscopy

• Step 3. Laryngeal exposure
  • Once epiglottis lifted then the view of glottis appears posterior to anterior
  • If poor view try externally manipulating larynx to improve the view, dynamic head elevation, BURP (backwards, upward, rightward pressure) and ensure position patient optimised

Figure- Vocal cord anatomy during intubation

Figure- Cormack-Lehane grading I, II, III, IV

• Step 4. Tube delivery

https://www.youtube.com/watch?v=E7Lo1JD2Brk (EM Crit, nd)

• • It is becoming more common to use a bougie for every intubation even if grade 1 – better to be confident in your chosen approach than using it for the first time in a difficult case
  • If using stylet have a 35-degree ‘hockey stick’ bed at the tip and make sure it doesn’t go further than the murphy’s eye of the ETT
  • Insert boogie below the line of sight and from the right corner of the mouth
  • Always have assistant load ETT onto the top of boogie and ensure boogie held
  • Gently deliver tube along bougie and through cords
  • If resistance withdraw ETT slightly and 90-degree anticlockwise motion to allow advancement
  • Once happy with the position, remove bougie
  • Inflate cuff and secure
  • Confirm placement of ETT – ETCO₂, visualisation of the tube through cords, misting of the ETT, chest wall movements, CXR

Figure- Top- bougie, Bottom- ETT rotation and passing through cords

 

• Complications can present as hypoxia or hypotension
  • The mnemonic ‘DOPES’ can be used to troubleshoot hypoxia (it’s not perfect)

• • • D – Displacement of ETT
    • O – Obstruction of ETT
    • P – Pneumothorax/bronchospasm
    • E – Equipment problem – ventilator issues
    • S – Stacked breaths/patient needs more sedation/paralysis

• Common causes of hypotension can be intubation medications causing vasodilatation, anaphylaxis, tension pneumothorax or worsening of preceding underlying issues
• A safe approach to managing these cases can be by assessing the situation logically from the ventilator to the patient
  • Remove patient from ventilator and hand-bag with BVM
  • Check tube position
  • Suction tube
  • Relieve pneumothorax – needle or finger decompression
  • Deflate chest if breath stacking
  • Deepen sedation/re-paralyse if dyssynchronous
  • Consider bronchodilators if wheeze
  • Fluid bolus for hypotension +/- inotropes
  • Adrenaline IM for anaphylaxis

 

LMA insertion – supraglottic airway device

https://litfl.com/laryngeal-mask-airway-lma/ (LITFL, 2019)

https://youtu.be/53VYGr4NZZs (Openairway.org, 2016)

https://www.youtube.com/watch?v=u95142tmlEY (Prof & Head Ram Nandan Prasad, 2016)

https://www.youtube.com/watch?v=Apt7jInQx2I (Painh8er, 2012)

 

• advantages
  • provide rapid protection of airway in the field
  • technically easier to insert than ETT
  • some models provide a gastric port
  • some models can be intubated through

• Disadvantages
  • non-definitive airway protection and patency
  • difficult ventilation if high airway pressures

• Multiple different types – worth seeing what is available in your workplace and being comfortable with insertion.

Figure- Types of LMA

• 1^st generation – simple airway device e.g. classic LMA (C)
• 2^nd generation – additional gastric port e.g. Proseal LMA (I), I-gel (H), LMA supreme (G) intubating LMA (A)
• 3^rd generation – cuffless, 2 drain tubes, small bowl e.g. Baska mask (E)
• Size 0 (infant) to 6 (large adult)
• Size 3 (females) or 4 (males) commonly used in adults but appropriate patient weight in Kg written on them

 

• Indications
  • Rescue airway in failed intubation (DAS/vortex)
  • Facilitate blind insertion of bougie of ETT into the trachea
  • Facilitated insertion of endoscopic assisted airway control
  • Improved oxygenation as part of a rapid sequence airway approach
  • Ventilation during elective anaesthetic to fasted patients with low risk of regurgitation

• Contraindications
  • Absolute – can’t open mouth, complete upper airway obstruction
  • Relative in elective settings
  • Increased risk aspiration – prolonged BVM, obesity, pregnancy, not fasted, upper GI bleed, suspected or knowns supraglottic anatomy abnormalities, need for high airway pressures (most LMAs can’t manage pressures over 20mm h20 – excluding Proseal)

• Predictor of difficult extra-glottic airway use ‘RODS’
  • Restricted mouth opening
  • Obstruction
  • Distorted airway
  • Stiff lungs or c spine

• Preparation – staff and area same as for ETT
  • Equipment – LMA of choice (+/- appropriate ETT/stabiliser if intubating LMA), lubricant
  • Drugs – You don’t necessarily need paralysis in a non-emergency setting

• Procedure
  • Blindly inserted to form a low-pressure seal over the laryngeal outlet
  • Sniffing position
  • Deflated cuff if a cuffed LMA
  • Lubricate mask surface
  • Aperture facing towards the laryngeal inlet
  • Inflate cuff with designated volume air if has an inflatable cuff
  • Commonly the LMA with move outwards with inflation

Figure- LMA insertion

• Complications
  • inability to achieve a seal and ventilate
  • regurgitation and aspiration
  • gas insufflation
  • partial airway obstruction (mask misplacement)
  • shaft kinking
  • malposition
  • dislodgement
  • laryngospasm
  • cough
  • trauma to the upper airway (e.g. bleeding, dislodgement of teeth)

• Post-procedure care
  • Adhere mask to face with appropriate tape/dressing
  • CO₂ monitoring

 

Surgical airway

https://youtu.be/DuLPCAM6ZhA (openairway.org, 2016)

• Needle cricothyroidotomy vs Surgical cricothyroidotomy
• Multiple techniques and kits available
• The most difficult step of this procedure is making the decision to move to the front of neck access
• PPE VIP
• Needle cricothyroidotomy – can oxygenation but not ventilate patient, can be extended to surgical if required and can help locate anatomy, unlikely to extensively distort anatomy, higher failure rate than surgical cricothyroidotomy
• Surgical cricothyroidotomy – can ventilate patient. Can perform small incision if easy to palpate anatomy, may require large vertical incision if difficult anatomy/obese etc. can extensively distort anatomy. Tactile procedure and should be able to be performed without visual cues (bloody field etc).

 

• Indications
  • Emergency surgical airway CICV (see vortex/DAS)
  • Predicted difficult airway – oedema, burns, bleeding – remember 2 teams, mark site and local if time, potentially try top end first but also consider awake fibreoptic intubation

• Contraindications
  • Unlikely if you’ve already committed to an airway
  • Ability to secure airway by less invasive means
  • Airway trauma e.g. laryngeal fracture, tracheal transection
  • Un-survivable injuries
  • Lack of equipment/skillset
  • NFR
  • Needle cricothyroidotomy recommended in <8-year-old

• Preparation
  • Staff – 2 teams – 1 for the front of neck access while another team may attempt traditional ETT
  • Area – Preferably in resus but will depend on the situation
  • Equipment – Depends on the choice of approach. As a general rule surgical cricothyroidotomy equipment will always be available, scalpel blade (e.g. size 10), bougie, size 6-0 ETT (or tracheostomy tube)
  • Drugs – potentially local with adrenaline if 2 teams and predicted diff intubation, otherwise patient will be sedated and paralysed for DAS/vortex front of neck access

• Procedure
  • Anatomical landmarks are the same for both needle and surgical approach
  • Extend neck with the patient supine and hold larynx with non-dominant hand ‘laryngeal handshake’
  • Dominant hand holds scalpel/needle and rests on the patient’s sternum for stability and support

Figure- Anatomical landmark for cricothyroidotomy

• Needle cricothyroidotomy – Not described here in detail but the below illustration is a good ‘macgyvered’ set up using readily available equipment.

Figure- Needle cricothyroidotomy kit

• Surgical cricothyroidotomy – Recommend using larger vertical incision as explained below.

https://vimeo.com/123573243 (Scott from EM Crit, 2015)

• 4 cm vertical incision through the skin over the cricothyroid membrane, may need to extend from mandible to sternum if impalpable anatomy
• Once skin incised, palpate cricothyroid membrane position and blunt dissect with fingers through subcutaneous tissue until the membrane is readily identifiable. Ignore bleeding until the airway is secure (ETT placement usually has a tamponade effect)
• Horizontal incision through the membrane, drag scalpel blade from one side to the other than turn knife through 180 degrees and extend to the other side. The cricothyroid membrane is bound by a ‘cartilaginous cage’ so resistance will be felt at the margins of the membrane when the scalpel blade abuts cartilage.
• Dilate with the gloved little finger and palpate tracheal lumen, ideally identifying the cartilage of the posterior wall of the trachea/ cricoid ring
• Pass bougie alongside little finger into the trachea
• Confirm bougie position with the finger, ensuring it passes through the membrane
• Bougie usually holds up at carina <10cm from the skin (may feel tracheal rings as the bougie advances), do not force if hold up as may perforate carina
• Pass ETT over bougie and intubate the trachea. Ensure the ETT balloon is fully deflated and twist ETT as it passes the skin (hold up here is common). Only advance the ETT until the balloon is within the airway and no longer visible
• Ensure ETT is held secure while bougie is removed and ETT is connected to BVM

Figure-Surgical airway

• Complications
  • Failure
  • Bleeding
  • Infection
  • Loss of airway
  • Damage to adjacent organs
  • Fistula formation
  • Scarring
  • Hypoxia
  • Death

• Post-procedure care
  • Confirm placement – CO2, auscultation, bilateral chest rise/call, fogging of the tube and chest x-ray
  • Secure ETT
  • ENT for definitive airway