21 Airway procedures

  • Face masks

    Ideally, facemasks should be clear to allow you to see:

    • The child's colour, and
    • The possible presence of vomit.
    • Some masks conform to the anatomy of the child's face and make providing a good seal relatively easy. These masks also have a relatively low dead space.
    • Circular soft plastic masks also give an excellent seal and are available across a range of sizes - from those designed to fit small neonates through to masks for large adults. Try to store a wide variety of sizes.
    • The correct size mask is one which fits over the mouth and nose but does not press on the eyes.

    Facemasks

    A guide to sizes of Laerdel silicone face masks 00 and 0/1 - Neonate - infant 2 - infant - small children 3 - small - large children 4 - Adult 5 - Large adult

    Jaw Thrust

    Jawthrust

    Jaw thrust manoeuvre

    • Jaw thrust is achieved by placing two or three fingers under the angle of the mandible bilaterally, and lifting the jaw upwards, ensuring the maintenance of in-line immobilisation.
    • Jaw thrust acts to lift the tongue off the back of the pharynx and so clear the airway.
    • This technique may be easier if the rescuer's elbows are resting on the bed or surface the child is lying on.

    Oropharyngeal Airway Insertion (OPA)

    • An OPA is indicated if the jaw thrust manoeuvre has failed to correct airway obstruction.
    • An OPA acts by establishing an opening between the tongue and the posterior pharyngeal wall and can make a difficult airway much easier to manage.
    • OPAs may not be tolerated by semi-conscious patients

    Guedelairway

    Guedel airways

    Equipment Required

    • Lubrication
    • Tongue depressor
    • Appropriate sized OPA

    Sizing

    Sizing airway

    Oropharyngeal Airway sizing

    • Measure from the centre of the incisors to the angle of the mandible, when laid on the face concave side up.

    Procedure

    • Pre-lubricate with either the patient's own saliva or a small amount of lubricating jelly.
    • Insertion: >8 years: like an adult: concave side up; pass to the back of the hard palate, then rotate 180o to concave side down
    • <8 years: insert under direct vision, concave side down, using a tongue depressor

    Outcome:

    • Correction of obstruction
    • Improved ventilation
    • If ventilation is still insufficient, the patient may require more advanced airway procedures, such as intubation

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    Endotracheal tube intubation

    Indications

    Failure to obtain an airway by simple airway opening maneuvers (eg: OPA insertion)

    Airway protection (eg: from blood, broken teeth, vomitus)

    To provide a secure airway for transport

    To control ventilation in the unconscious/head injured patient 

    Endotracheal tubes

    • Uncuffed tubes are preferable in children up to eight years of age, to avoid oedema at the cricoid ring.
    • Finding the right-sized tube is important, to avoid large leaks around the tube.
    • Nasotracheal intubation whilst more secure is contra-indicated in patients with possible base of skull fracture

    Sizing:

    Diameter Neonate - 3.0 mm 0-6 months -3.5mm 6-12 months -4.0 mm Then use (Age in years / 4) + 4 = size of endotracheal tube (ET) mm

    Length of insertion at lips:

    Visualise the tube passing through vocal cords avoiding endobronchial intubation:

    Endotracheal tubes

    endotracheal tubes

    Newborn

    |

    10 cm

    1 yr

    |

    11cm

    2 yr

    |

    12 cm

    3 yr

    |

    13 cm

    4 yr

    |

    14 cm

    6 yr

    |

    15 cm

    8 yr

    |

    16 cm

    10 yr

    |

    17 cm

    12 yr

    |

    18 cm

    Formula for length (at lips) of oral tube is Age/2 + 12

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    Laryngoscope:

    Curved or straight blades can be used although the straight blade laryngoscope is recommended in young children, because:

    • It is designed to lift the epiglottis, which is comparitavely large and floppy in children, under the tip of the blade, allowing a better view of the vocal cords; 

    Preparation for Endotracheal intubation:

    • An assistant, who is familiar with intubation equipment, is essential.
    • Endotracheal tube: Calculate the appropriate size: Age/4 + 4 mm = internal diameter (ID)

    Have tubes of the appropriate size, plus tubes 0.5 mm ID smaller and 0.5 mm ID larger than that size, available on the child's bed.

    • Introducer: for ET tubes 4.5 mm ID and smaller, a lightly lubricated stilette inserted almost to the tip of the tube, makes intubation easier.
    • Oral: Always use oral - never nasal - intubation in a child with a head injury, because of the risk of meningitis, and of entering the cranial cavity if there is an undiagnosed fracture of the skull base.
    • Laryngoscopes: Have 2 available. Check the light is bright enough.
    • Suction: -Check it is working. -Use a Yankauer suction catheter. -Place it next to the child's head.
    • Drugs: Draw up and label [see below] -
      • Saline flush 10 ml.
    • IV cannula + 3-way tap on extension tubing: all patent and visible
      • Have your assistant ready to:
    • Apply Cricoid pressure -Use direct pressure on the cricoid - thumb & index finger both side, and press directly down.
      • Start as the first drug is injected.
      • Don't stop pressure until the ET tube is in place and secure.
    • Give Drugs:
      • Hypnotic first, then flush.
      • Muscle relaxant, then flush.
      • Hand you Equipment: In the correct order?

    Rapid sequence induction of anaesthesia:

    Used whenever the stomach may not be empty (i.e. in every injured child)

    1. Pre-oxygenate the child:

    • High flow O2;
    • Tightly fitting mask;
    • Three minutes if possible.

    2. Drugs: Always used unless the child is flaccid and unresponsive.

    • 1st Hypnotic such as thiopentone (3-5mg/kg), midazolam (0.5 mg/ kg) or propofol (2-4 mg/kg);
    • 2nd Muscle relaxant such as suxamethonium (1 mg/kg) or rocuronium (1mg/kg).
    • Remember, rocuronium is a relatively long acting muscle relaxant and should not be used if intubation is expected to be difficult.
    • Hypnotic doses should be at the lower end of the range in hypovolaemic patients. 

    3. Intubate the trachea as soon as relaxed; 

    Avoid unnecessary bag and mask ventilation prior to intubation as this may inflate the stomach, increasing the risk of aspiration.

    Laryngoscope: hold in your left hand. Be gentle.

    < 1 year: Straight blade (Miller or Robertshaw).

    • Pass the tip over the tongue past the tip of the epiglottis.
    • Lift the epiglottis to see the vocal cords.

    Straight blade laryngoscope

    > 1 year: Curved blade (MacIntosh 2 or 3):

    • Pass the tip over the tongue into the vallecula (space between tongue and epiglottis).
    • Lift the handle towards the ceiling at the far end of the room to bring the vocal cords into view.
    • Don't lever against the teeth.
    • Don't jam the lip between blade and teeth.

    Curved blade laryngoscope

    4. Insert the endotracheal tube.

    • Calculate how far. [(Age/2) + 12] cm at the teeth.
    • Immobilise the tube at the lips.
    • Auscultate both axillae and epigastrium to confirm the tube position.
    • Secure with cotton tape around the neck, or Elastoplast on the face.

    5.Insert an orogastric tube on free drainage. Never use a nasogastric or nasotracheal tube in a child with a head injury (because of risk of meningitis, or of entry of cranial cavity in undiagnosed fracture of the skull base).

    6. Check AP chest Xray: The ET tube tip should lie at the level of the medial end of the clavicles. If not, re-position the tube and re-tape.
    7. Suction the ET tube carefully each hour - more often, if needed.
    8. Humidify the inspired gases using a condenser humidifier (Swedish nose) between the ET tube and the self-inflating bag.
    9. Splint the child's arms if necessary (child should be sedated)

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    Needle Cricothyroidotomy

    If the airway is completely inadequate, consider:

    • Surgical cricothyroidotomy (> 12 years)
    • Needle cricothyroidotomy (any age; may be used to gain time during surgical cricothyroidotomy)

    Rationale for needle cyricothyroidotomy

    • Patent airway not possible by other means.
    • Preferable to surgical airway in children under 12 years of age.
    • Useful for obstruction in the larynx or above; not if the obstruction is in the trachea or bronchi.
    • It improves oxygenation slightly, buying 10-15 minutes' time for help to arrive and for a definitive airway to be established.

    Preparation for Needle Cricothyroidotomy

    • Continue bag/mask ventilation with O2
    • Prepare equipment:
    • IV cannula: largest available (10 - 16 SWG), with 5 ml syringe;
    • Oxygen tubing + 3-way tap. (If there is no 3-way tap available, cut a 3mm hole in the side of the O2 tubing and, if necessary, cut the O2 tubing to fit over the hub of the cannula.)
    • Place a rolled towel under the child's shoulders.

    Surface markings

    Feel your own cricothyroid membrane: this is the horizontal gap between the thyroid cartilage (Adam's apple) above, and the horizontal cricoid cartilage below.

    Surface-marking

    surface markings

    • Stand on the child's left and locate the same structures.
    • Immobilise the trachea between your left finger and thumb.
    • Insert the cannula through the cricothyroid membrane, then 45o downwards towards the feet. STAY IN THE MIDLINE!
    • Aspirate continuously as soon as the needle is through the skin.
    • When you can aspirate air, the needle is in the trachea. Immobilise the syringe (don't pull it back) and slide the cannula down the needle into the trachea.
    • Tape the cannula in place.
    • Attach the O2 tubing to the cannula.
    • Run O2 at 1 litre/min per year of age.

    Insertion needle

    450 angle

    • Occlude the side hole of the 3-way tap, or the hole in the O2 tubing, for 1 sec, then release for 4 sec to allow expiration.

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    Complications to be aware of

    • Asphyxia
    • Aspiration
    • Cellulitis
    • Oesophageal perforation
    • Haemorrhage
    • Haematoma
    • Posterior tracheal wall perforation
    • Subcutaneous and/or mediastinal emphysema
    • Thyroid perforation
    • Inadequate ventilation leading to hypoxia and death