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Information ⬇

Author: Matthew Frise

The upper airway runs from the mouth and nose to the carina. Upper airway obstruction (UAO) is a condition where functional or mechanical factors lead to loss of normal airway architecture and patency, compromising ventilation.

  • Upper airway obstruction is a life-threatening medical emergency. Precipitous deterioration may occur without warning, so treatment must be swift.
  • Causes are given in Appendix 59.1 and Table 59.1. Intervention may need to precede a definitive diagnosis.
  • It is important not to make the situation worse by incorrect positioning, for example lying the patient flat, attempting intubation if inexperienced, or giving sedative drugs with an unsecured airway.

Priorities ⬆ ⬇

Outline

Don't Make the Situation Worse!!navigator!!

  • Often simple manoeuvres are all that are required until more experienced help arrives.
  • The use of airway adjuncts and attempted intubation in inexperienced hands may worsen the situation and make subsequent attempts at establishing a definitive airway more difficult.
  • The conscious patient will often try to assume the position which best relieves obstruction; help the patient to do this. In tracheal compression or laryngeal tumours, lying the patient flat can provoke complete obstruction and respiratory arrest.
  • Sedative drugs must be used with extreme caution in patients with possible UAO; sedation before the airway is secured may precipitate respiratory arrest.

Re-Establish Airway Patency to Permit Adequate Ventilation, Whilst Preventing Aspiration!!navigator!!

  • If the patient is conscious and choking as a result of acute severe airway obstruction by a foreign body, give alternating sequences of five intrascapular back blows and five abdominal thrusts.
  • In other conscious patients with suspected UAO:
    • Give high flow supplemental oxygen via non-rebreathe mask whilst making a rapid clinical assessment (Table 59.2). The airway may be lost at any time, leading to hypoxic cardiac arrest, so do not withhold oxygen due to misplaced concerns about toxicity.
    • If there are any features suggestive of anaphylaxis give IM adrenaline 500 μgm immediately and summon help. Treat according to ALS guidelines (see Chapter 38). If there is cardiovascular instability raise the legs rather than lying the patient down and do not instrument the airway unless suitably experienced. If the patient arrests in the meantime, follow ALS guidelines (see Chapter 6).
    • Secure IV access, ideally large bore. If intubation is likely at least two IV access points should be available.
  • If the patient is unconscious and has signs of obstruction such as snoring:
    • Check the airway is clear of debris, suction if necessary and manipulate the airway to see if obstruction can be relieved.
    • Consider an oro- or nasopharyngeal airway (see Chapter 112).
    • If the patient is breathing place in the recovery position with adjuncts and supplemental oxygen in situ.
    • If there is concern about cervical spine injury, use manual in-line stabilization, but the airway takes priority.
    • If there is inadequate or absent respiratory effort despite relief of obstruction, ask for the arrest team to be summoned whilst commencing bag-mask ventilation using 100% oxygen. If this is ineffective, insert a supraglottic airway such as a laryngeal mask airway or an i-gel®. If still ineffective and more experienced help is yet to arrive, attempt endotracheal intubation if appropriately experienced.
    • If at any point cardiac output is lost, follow the ALS algorithm.

Continue Your Assessment!!navigator!!

  • If the patient is conscious obtain a brief history (Table 59.2); yes/no answers may be all that is possible.
  • Examine the patient. Look closely at the thorax, head and neck for swelling, masses, previous surgical scars (especially from tracheostomy or neck dissection), distended veins or distorted anatomy. Listen carefully for stridor.
  • If the features suggest mechanical obstruction summon urgent ENT assistance.
  • Optimize the patient's position and stay at the bedside.

Further Management ⬆ ⬇

Outline

Some causes of UAO, such as anaphylaxis, are reasonably quickly reversible and once the patient has recovered from the acute event, extubation can be attempted.

Medical Therapies for Mechanical Upper Airway Obstruction (Uao)!!navigator!!

These are based on relatively little evidence but can be considered (Table 59.3).

Further diagnosis

  • Disorders of consciousness that have compromised the airway should be managed as discussed in Chapters 3 and 112.
  • For mechanical UAO several approaches to diagnosis are available:
    • Fibreoptic endoscopy: allows visualization of the upper airway under local anaesthesia usually via the nose, but may also be performed orally or via an endotracheal tube (ETT) or tracheostomy. It has the advantage of also permitting awake fibreoptic intubation of a patient with UAO who is able to sit up and cooperate, avoiding the risks of a rapid-sequence induction (RSI) in this setting.
    • Radiographs: plain films of the thorax and neck may locate a foreign body or tracheal distortion, and can be undertaken in the resuscitation room without the need to move the patient. These may also reveal evidence of complications such as aspiration, negative pressure pulmonary oedema or pneumothorax.
    • CT: in a stable patient who is able to lie flat, or otherwise once a definitive airway has been secured, gives excellent cross-sectional imaging of the relevant anatomy and will reveal most pathologies of interest.

Consider a surgical airway

  • This is needed if the cause of UAO is not quickly reversible, for example laryngeal tumour or bilateral vocal cord paralysis.
  • Seek advice from an ENT surgeon. Formation of a tracheostomy is increasingly undertaken percutaneously by critical care physicians using the Seldinger technique.
  • For the patient with UAO, anatomical considerations may make surgical formation in theatre preferable.

Problems!!navigator!!

Transport of the patient with a compromised airway

  • If a patient with a compromised airway and/or impaired consciousness requires transfer to another area, such as for diagnostic imaging, careful consideration should be given to intubation beforehand. Doing so in a controlled manner and well-resourced environment of the resuscitation room is far preferable to attempting advanced airway interventions in a CT scanner with limited equipment when the patient has vomited and aspirated.
  • If a patient with UAO needs to lie flat (and still) for imaging, intubation may be required in any event.

Aspiration of gastric contents

  • Aspiration pneumonitis is a chemical process resulting from lung injury by gastric acid. In the self-ventilating patient, this requires supportive therapy with supplemental oxygen and possibly continuous positive airway pressure (CPAP).
  • If true aspiration pneumonia develops as a result of superinfection, antibiotic therapy should be instituted in line with local guidance (see Chapter 63). Evidence is lacking to support the use of empirical antibiotic therapy in all patients with evidence of aspiration.
  • Aspiration is the commonest cause of death associated with airway management during anaesthesia.

Negative-pressure pulmonary oedema

  • Occasionally the negative pressures generated by a patient's vigorous ventilatory effort in the face of UAO can cause pulmonary oedema.
  • Confusingly, this may develop some hours after relief of the obstruction, and misdiagnosis as acute cardiogenic pulmonary oedema or aspiration is possible (Chapter 47).
  • Treatment is with supplemental oxygen and CPAP. Depending on volume status, loop diuretics may be helpful.

The patient with a tracheostomy

  • Following the national tracheostomy safety project, adult inpatients with a tracheostomy should all have clear guidance at the bedside indicating steps to be taken in the event of an emergency – follow these if called to an acutely ill inpatient with a tracheostomy.
  • For patients presenting with signs of airway compromise and a tracheostomy, the priorities are to summon expert help and deliver oxygen by whatever means possible until assistance arrives. General steps are as follows:
    • Give high flow oxygen via the stoma and face.
    • Remove the inner tube and try to pass a suction catheter – if it passes easily, suction and leave the outer tube in place. If respiratory effort is poor or lost, ventilate via the tracheostomy (may need inner tube replaced to attach circuit).
    • If a suction catheter cannot be passed, deflate the tracheostomy cuff and see if this relieves the obstruction. If so leave the cuff down and continue oxygen.
    • If obstruction persists remove the tracheostomy altogether. Occlude the stoma and attempt ventilation from above using BMV with adjuncts or an LMA. If this fails try ventilation via the stoma using a bag and paediatric mask.
  • Patients with laryngectomies cannot be ventilated or intubated from above since they do not have an airway above the stoma. Oxygen applied to the face will not be useful for this reason. The default position in the emergency setting where the exact anatomy may not be clear is to apply oxygen to the stoma and the face.

Can't intubate, can't ventilate

  • The situation where endotracheal intubation fails and ventilation with bag and mask is impossible is well recognized. Try an LMA or an i-gel® early; if these fail, other options in sick medical patients, for the appropriately experienced, include:
    • Retrograde intubation: a guidewire is passed percutaneously across the cricothyroid membrane and up into the retropharynx and the end captured with a pair of forceps; this is then used to guide an ETT into the trachea.
    • Transtracheal jet ventilation: a very high pressure oxygen source is used in bursts via a large-bore catheter (IV or specifically-designed) inserted through the cricothyroid membrane. Provides temporary relief of hypoxia but carries serious risks of potentially fatal barotrauma and subcutaneous emphysema. Contraindicated if complete UAO prevents expiration.
    • Cricothyroidotomy: the surgical treatment of choice to re-establish airflow if other interventions fail. A horizontal incision is made through the cricothyroid membrane and a small ETT inserted allowing manual ventilation with 100% oxygen. A formal surgical tracheostomy under local anaesthesia is also an option if available without delay.

Further Reading ⬆

Al-Qadi MO, Artenstein AW, Braman SS (2013) The ‘forgotten zone’: acquired disorders of the trachea in adults. Respir Med 107, 1301–1313. DOI: 10.1016/j.rmed.2013.03.017.

Patel A, Pearce A (2011) Progress in management of the obstructed airway. Anaesthesia 66, Suppl 2, 93–100. DOI: 10.1111/j.1365-2044.2011.06938.x.