Airway management and assisted ventilation in an emergency

Essentials

  • Respiratory insufficiency is managed by ensuring a patent airway and assisting ventilation. The most common causes of loss of airway patency and/or respiratory insufficiency are cardiac arrest, impaired consciousness or critical respiratory distress.
  • The simplest way to ensure airway patency and to assist ventilation is to open the airway manually and to start assisting ventilation using a bag-mask attached to oxygen.
  • The airway must be kept patent and maintained using an airway device, such as an oropharyngeal (oral) or supraglottic airway, an endotracheal tube or by an emergency tracheotomy.
    • An oral airway can be used initially for assisted ventilation with a bag-mask.
    • A supraglottic device should be used as the primary airway device.
    • Tracheal intubation should only be performed by anaesthesiologists, intensive care, prehospital or other emergency care specialists, who are well acquainted with and competent in this skill.

Primary measures

  • In patients with cardiac arrest or impaired consciousness, assisted ventilation should primarily be started using a bag-mask attached to oxygen.
  • If in hospital, always ask for further assistance.
  • In primary health care, act according to local guidelines and/or call the emergency number (112) to get support from emergency services for treatment and to have them take the patient for further treatment, as necessary.
  • To facilitate bag-mask ventilation, an oral airway should be inserted, as necessary (Image (Insertion of an oral airway)).
    • Choose a size 3–4 oral airway for an adult, a smaller one for a child. The correct length is the distance from the corner of the patient’s mouth to the earlobe.

Choice of airway device

  • Laryngeal mask airway, LMA
    • The correct size depends on the manufacturer and the model.
  • Laryngeal tube, LT
    • For choice of size, see Table T1.
  • i-gel®

The most common problems

  • Placement of the laryngeal mask airway (LMA) does not result in a good seal.
    • Wrongly chosen size of device
    • Device introduced obliquely into the pharynx
    • Fix the problem by reinserting the device.
  • The laryngeal tube (LT) does not produce a good seal.
    • Make sure that the cuff is intact and the air volume correct.
    • Check the correct depth (deflate slightly, as necessary, insert at correct depth, fix carefully).


Table 1. Choosing the size of laryngeal tube (LT-D)

Patient’s weight/height LT-D colour* LT-D no.
Child 12–25 kg green 2
125–150 cm orange 2.5
Adult < 155 cm yellow 3
155–180 cm red 4
> 180 cm purple 5
* The corresponding colour on the syringe shows the maximum cuff filling volume.

Assisted ventilation

  • After inserting the airway device, continue assisted ventilation using a bag attached to the airway device.
    • The tidal volume for an adult patient is approx. 500 ml and the respiratory rate 15 per minute.
  • Make sure that the patient’s chest rises with each ventilation and that the ventilation is effective (Table T2).

Monitoring devices

  • All patients should have
    • 3-lead ECG monitoring
    • expiratory carbon dioxide monitoring (etCO2, capnograph) with graph display.
  • If the patient has a rhythm with pulse, a SpO2 sensor and automatic pneumatic noninvasive blood pressure (NIBP) monitoring should be used in addition to monitoring the rhythm.

Table 2. Monitoring the success of ventilation
Observation Issues to be observed
Does the chest rise? Does the mask sit tightly on the face?
Is the mask of the right size?
Are the head position and the grip correct?
Is the oral airway of the right size? The oral airway must be measured before insertion. The correct length is the distance from the corner of the patient’s mouth to the earlobe.
If the oral airway is of the wrong size, it will obstruct rather than open the airway.
Is air going into the stomach? Make sure that the airway is patent.
Sufficiently long inspiration (approx. 1 s) synchronized with compression (in the case of cardiac arrest)
Is the airway device (supraglottic or endotracheal tube) in the correct position? Correct positioning must be ensured immediately after insertion primarily based on the expiratory carbon dioxide flow curve.
Auscultate breath sounds.


Copyright © 2020 Duodecim Medical Publications Limited.
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