Question 22

College Answer

This is an emergency situation with the following key issues:

Rapid deterioration in a patient with airflow limitation 
Preparation for a difficult intubation

Management comprises simultaneous resuscitation and assessment to diagnose the cause(s) of the rapid deterioration in this patient and initiation of supportive and definitive management and at the same time calling for help and preparing for a difficult intubation.

Prompt diagnosis and appropriate focussed management of the underlying cause(s) may obviate the need for intubation in this patient but should not delay intubation if this needs to be done.

Help should be sought from the most appropriate resources available (senior ED or anaesthetic colleague, ENT, skilled anaesthetic technician)

Diagnosis of underlying cause depends on history, examination and specific investigations. Possible causes of rapid deterioration in this patient include tension pneumothorax, worsening bronchospasm, pneumonia and septic shock, pulmonary embolus, myocardial ischaemia. Treatment measures may include thoracocentesis / insertion ICC, bronchodilators, fluid and vasopressor resuscitation and antibiotics, thrombolysis, reversal coronary ischaemia.

Consideration should be given to a trial of NIV but again this should not delay necessary intubation.

If the underlying problem is not readily reversible, proceed to securing the airway with preparation for difficult intubation.

Preparation for difficult intubation involves the following:

Location 
Patient unsuitable for transfer to OT so use well-equipped resus bay in ED

Equipment

Standard intubation equipment plus difficult airway trolley including equipment for emergency surgical airway, resuscitation equipment and full monitoring and ETCO2

Drugs

Sedatives, muscle relaxants, resuscitation drugs and local anaesthetics

Personnel

Experienced assistants for airway equipment, drugs, cricoid pressure and general help Experienced colleague (ICU, anaesthesia, ED, ENT)

Technique

Assess patient’s airway and information regarding previous intubations and nature of difficulty and ease of bag-mask ventilation. It may be appropriate to perform immediate tracheostomy or cricothyroidotomy under local anaesthesia. Difficult to intubate BUT easy to ventilate increases options.

• Plan A: attempted intubation under direct laryngosopy optimizing position and using adjuncts and if fails: 
• Plan B: Intubating LMA and if fails:
• Plan C: able to ventilate via LMA, controlled surgical airway OR if unable to ventilate via LMA emergency surgical airway (cricioidotomy or cricoidostomy)

Discussion

Whenever one is asked to "outline the priorities", one shoud probably begin with attention to the immediate ABCs of management.

After that, the priorities here are firstly the management of acute respiratory failure, and secondly the preparation for a difficult intubation.

Immediate attention to ABCs:

• Assessment of the need for immediate intubation
• Support of airway with airway adjuncts eg Guedel or nasopharyngeal airway
• Support of oxygenation with high-flow oxygen and/or NIV
• Assessment of coexisting circulatory failure with rapid bedside TTE and lung ultrasound to exclude immediately reversible causes eg. pneumothorax and cardiac tamponade or acute decompensated heart failure
• Support of circulation with appropriate vasoactive agents

Management of respiratory failure:

• Detailed history and thorough physical examination
• ABG, ECG and CXR +/- CTPA (if permited by patients condition)
• Support of oxygenation with titrated FiO₂
• Support work of breathing with NIV
• Support ventilation by titrating NIV pressures to enhance CO₂ clearance
• Manage bronchospasm with bronchodilators and steroids
• Manage infective aetiology with appropriate antibiotics

Preparation for a difficult intubation:

• Transfer patient into controlled monitored environment - resus bay, ICU or operating theatre
• Contact appropriate airway experts - a senior anaesthetist and ENT surgeon are sensible consults
• Organise the difficult intubation equipment trolley
• Prepare skilled staff to assist
• Prepare equipment and brief patient regarding the need for intubation
• Assess the airway and investigate past history of intubation to determine what equipment was required in previous instances
• Options for intubations:
  • Awake bronchoscopic intubation is the gold standard
  • If the expertise for this is not available:
    • Plan A: Video-assisted laryngoscopy with availability of gum elastic bougie
    • Plan B: insertion of intubating LMA and intubation via LMA or ventilation with LMA until the necessary expertise becomes available
    • Plan C: percutaneous cricothyroidotomy or formal surgical airway

A generic list of difficult airway equipment to have ready:

• A selection of oropharyngeal airways
• A selection of nasopharyngeal airways
• Macintosh laryngoscope blades size 3 and 4.
• Alternative laryngoscope blades (eg. a Kessel blade)
• A short laryngoscope handle (for fat or big-breasted people)
• An endotracheal tube introducer
• A malleable blunt atraumatic stylet.
• Normal LMAs of different sizes
• Intubating LMA kids, eg. Fastrach
• A selection of specialised ETTs, eg. long flexometallic, nasal, etc.
• A long airway exchange catheter.
• A surgical cricothyroidotomy kit
• A kink resistant cricothyroidotomy cannula and jet ventilation kit
• A capnograph, capnometer or colorimetric end-tidal CO₂ detector.

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Oh's Intensive Care manual: Chapter 58  (pp. 629) Diabetic  emergencies  by Richard  Keays

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