Airway and Ventilation Management

Airway problems
Securing an airway
Airway decision scheme
Oxygenation
Ventilation

Airway Problems

Airway kills fast
Common cause of avoidable mortality is not securing the airway
- recognise the need for an airway
- secure the airway.
- recognise an incorrectly placed or a displaced airway
- recognise the need for ventilation
- prevent aspiration

Problem Recognition
Compromise may be
- sudden and complete
- insidious and partial
- progressive and/or recurrent.
--> frequently reassess.
Unconscious are at particular risk of hypoxia and hypercarbia
- intubation provides an airway, delivers O2, supports ventilation and prevents aspiration.
Aspiration should be anticipated
--> immediate suction, role entire patient to lateral position.

Objective Signs
Remove the helmet.
Talk to the patient first
- a positive and appropriate response indicates a patent ventilating airway with brain perfusion.
- otherwise there is airway/ventilation compromise or altered consciousness.
Inspect
Obtunded (hypercarbia), agitated (hypoxia - don't presume intoxication).
Cyanosis (hypoxia)
Refusing to lie down.
Accessory muscle use.
Noisy breathing is obstructed.
Snoring, gurgling crowing (stridor) - partial occlusion.
Hoarseness - dysphonia - functional laryngeal obstruction.
Neck haematomas - can obstruct
Material in mouth - blood, teeth, vomitus
Palpate
Ensure trachea is midline

Maxillofacial trauma
 Mid-face #/dislocation compromises the naso & oropharynx.
- associated haemorrhage, secretions and teeth cause additional problems.
Mandibular #s (esp bilateral) causes loss of support
--> obstruction in the supine position

Neck trauma
Penetrating injury
- can cause haemorrhage, airway displacement & obstruction
--> urgent surgical airway required.
--> operative control may be required.
C-spine immobilization unnecessary in penetrating trauma; may delay correct care
Laryngeal/trachea disruption
Initially these pts may maintain patency & ventilation
- can be accompanied by bleeding into the tracheobroncheal tree
- if compromise suspected --> definitive airway
- can be obstructed from outset --> urgent definitive airway.
Insert the ET tube cautiously else the existing injury may extend.
- if patency being lost, a surgical airway is usually indicated.

Laryngeal trauma
Noisy breathing indicates partial/threatened airway
Absence suggests obstruction.
In an unconscious patient, laboured resps may be the only feature.
Laryngeal fracture
Rare but can be life threatening.
- triad of hoarseness, subcutaneous emphysema, palpable fracture.
If totally obstructed
--> attempt intubation, flexible endoscopic guidance if available.
--> if unsuccessful, emergency tracheostomy (difficult and may invoke bleeding and take time)
--> surgical cricothyroidotomy may be life-saving, although not preferred
CT can identify subtle larynx fractures.
Penetrating trauma
Requires immediate attention due to risk of transection or occlusion
- oesophageal, carotid and jugular injury may be associated.


Securing an Airway

1. Provide supplemental oxygen before and after airway management.
2.  Maintain C-spine protection

Recognise difficulty

Beard, poor dentition, short mandible, tooth loss
Poor mouth opening / poor view
- Mallampati designed for pts sitting up spontaneously opening mouths
Oropharyngeal bleeding

Tongue obstruction

- readily corrected with chin lift and jaw thrust
- maintain with oropharyngeal or nasopharyngeal airway

Multilumen oesophageal airways
are sometimes used by prehospital staff
- one communicates with trachea (ventilated), one with oesophagus (ballooned).
- remove it after appropriate assessment.
- similarly check position of any tube placed in the field, after transport.

Laryngeal masks
Are not a definitive airway.
- difficult without training and role in trauma  not defined.
- if in place, decide whether to continue or remove & intubate.

Definitive Airway
Tubed with cuff inflated and oxygen-rich assisted ventilation, secured with tape
Three types:
1. Orotracheal intubation
2. Nasotracheal intubation
- requires breathing
- avoid in pts with Battle sign, raccoon eyes rhinorrhea, otorrhoea, midface #s.
3. Surgical airways (see below)
Once placed supplemental sedation, analgesics and muscle relaxants may be required.
C-spine injury is of major concern during intubation.
May need rapid sequence intubation in the awake patient in an acute setting.

Decision to place depends on
:
1.  Expertise of the doctor
2.  Need for protection
- impending or potential compromise
- eg inhalation / facial injury, sustained seizures
- eg blood / vomit aspiration risk
- eg retropharyngeal haematoma, larynx/trachea injury, stridor
3.  Need for ventilation
- apnoea (paralysis, unconscious GCS<=8)
- inadequate respiration (tachypnoea, hypoxia, hypercarbia, cyanosis)
4.  Clinical findings
- urgency, need and type dictated by scenario
- pulse oximeter may help decision.
- so might this algorithm:

Indications for definitive airway
Resp insufficiency
Airway obstruction
GCS<=8
Severe maxillofacial trauma
- can obstruct, bleed into airway, distort anatomy complicating intubation
Thermal airway injury
- suspect in all burns
- esp if singed nasal hairs, carbonaceous sputum, face burns.
- intubate, do not wait until progression of oedema, hoarseness and stridor.
Persistent agitation.
- rule of 3: if physically or verbally assaults the team 3 times, intubate.

Large / expanding neck haematoma
Penetrating airway injury

Airway Algorithm

Severe maxillofacial injury
Attempt intubation
--> surgical airway if unable

Apneic
Orotracheal intubation with in-line immobilization
--> surgical airway if unable.

Breathing
Nasotracheal / orotracheal intubation with in-line immobilisation
--> pharmocologic adjunct if unable
--> surgical airway if still unable

Rescue Techniques

LMA
- does not protect airway
- may be useful temporizing measure when intubation unsuccessful
- do not use when massive maxillofacial trauma or pregnancy >16w
Video Laryngoscopy
- fibreoptic visualization of pathway
- less movement of c-spine
- useful in the morbidly obese; limited neck mobility; any difficult airway
Flexible fibreoptic bronchoscopic-assisted intubation
- advanced technique
- ETT preloaded over flexible bronchoscope, intubated

Surgical Airways
Indicated when unable to intubate the trachea
- eg glottis oedema, fracture of the larynx, severe oropharyngeal haemorrhage.
Surgical cricothyroidotomy is usually preferred to tracheostomy
- less bleeding & quicker.
1. Jet insufflation
- can be useful short-term in emergency situations
- not if pt has abnormal pulmonary function or significant chest injury.
- lower flow to prevent barotrauma in persisting foreign body obstruction of the glottic region.
- never seen it done though...
2. Cricothyroidotomy
- may need to briefly remove collar and immobilise neck during procedure.
3. Emergency tracheostomy
- less commonly used
- may be necessary if tracheal disruption, direct airway injury / larynx #
- preferable in children as cricothyroidotomy can damage larynx.
4. Percutaneous tracheostomy
- highly selective, only by those with substantial non-urgent case experience
- otherwise best to use open techniques with optimal control in emergency.

Airway Decision Scheme

1.  Assure oxygenation and C-spine immobilisation
- chin lift, jaw thrust, basic airways.

2. If showing respiratory effort
--> pass a nasotracheal tube (? - really?; never seen it)
If not
--> endotracheal tube under in-line immobilisation

3.  If unable to intubate / contraindicated
--> cricothyroidotomy

Key Questions
1. Does patient need to be intubated?
2. How quickly?
3. Will it be challenging?
4. What is the best method?
5. What is the back-up plan if it fails?


Oxygenation

All patients
Tight fitting O2 reservious face mask
- flow rate 11L/min.
Nonrebreather masks can improve concentation.

Pulse oximetry
Especially important for transport, or difficulties with airway predicted.

Ventilation

Problem recognition
Ventilation depends on the airway, ventilatory mechanics and the NCS.
If clearing the airway does not help breathing, find another source.
Direct trauma
--> pain with rapid shallow resps and hypoxia.
--> especially dangerous in those with preexisting chest problems.
Head injury
--> abnormal breathing patterns.
C-spine injury
--> diaphragmatic breathing and hypoxia
--> or paralysis requiring assisted ventilation.
Difficult to bag-valve mask if:
- facial hair
- midface #s
- combative pt
--> secure airway

Objective signs
Inspect
Asymmetrical chest excursion
- eg flail splinting (immediate threat)
Tachypnoea may represent 'air hunger'.
Auscultate
Decreased or absent breaths
- eg intrathoracic injury
Pulse oximetry
Essential.
Helps know sats, perfusion, but does not assure adequate ventilation.

Management
2 person bag-valve-masking is better than one.
- one person holds with jaw thrust for a good seal
- another squeezes bag every 5 seconds with both hands.
- flow rate 12L/min
- assess success by chest expansion.
Intubated ventilation
- proceed with positive pressure breathing.
- either volume or pressure regulated respirator.
- be alert for complications (eg pneumothorax).

Difficult airway

Principles of airway Mx

Assess

Intervention

Early intubation

LOC (<10)

Craniofacial injuries

Burns

Chest injury

Shock

Multitrauma

v Use drugs only if can be confident of controling airway & ventilation

Post intubation

C02 detection

Breath sounds

Secure tube with tie

Airway bleeding

Suction

Foleys

Packing

Posture

Airway exchange catheter

Laryngeal trauma