What is true of the airways in children compared to adults?
There are many anatomical airway differences between infants, children, and adults, and the younger the child, the more pronounced the difference
What is the importance of the difference in childrens airways?
It has relevance to emergency care, particularly airway opening manoeuvres, airway adjuncts, and endotracheal intubation
Why can life threatening airway obstruction develop rapidly in children?
As the airway is already narrow, and further airway narrowing from any cause increases resistance according to Pouseuille’s law
How is Pouseuille’s law applied to airways?
As resistance is inversely proportional to the fourth power of the radius, a small reduction in an already small airway radius will result in a large increase in resistance
What can neck flexion or overextension lea to in infants?
Airway obstruction by tracheal compression
Why can neck flexion or overextension lead to airway obstruction in infants?
Due to the relatively large head and short neck in infants
What else can cause airway obstruction in infants?
The relatively large tongue
When in particular can an infants tongue cause airway obstruction?
If there is a reduced level of consciousness
What other problem might the tongue cause?
May impede the view at laryngoscopy
What manoeuvres are used to open the airway in children?
- Head tilt/chin lift
- Jaw thrust
How do airway manoeuvres used in children work?
They apply anterior tension to the hyoid bone and draw the epiglottis away from the posterior pharyngeal wall, opening the pharynx
In addition to drawing the epiglottis away from the pharyngeal wall, how else does jaw-thrust improve airway potency?
It pulls the tongue, which may cause airway obstruction, away from the palate and opens the oropharynx
What care must be taken when performing airway opening manoeuvres in children?
When positioning the fingers, as the floor of an infants mouth is easily compressible
What is it important to do when performing head tilt/chin lift in an infant?
Control the degree of head tilt to avoid airway narrowing due to overextension of the head and neck
What head position is preferred when opening the airway in an infant?
Neutral position
Why is a neutral position preferred when opening the airway in an infant?
Due to the large head and short neck
What head position is used when opening the airway in a child?
The sniffing position
When is the head tilt/chin lift manoeuvre contraindicated?
If there is a history of trauma
Why is the head tilt/chin lift manoeuvre contraindicated if there is history of trauma?
It may exacerbate cervical spine injury
What is the purpose of an oropharyngeal airway, or Guedel airway?
It creates an open channel between the mouth to the posterior pharyngeal wall
When are oropharyngeal airways used?
Only in infants and children with reduced level of consciousness
Why are oropharyngeal airways only used in infants and children with reduced level of consciousness?
As they may cause choking or vomiting if the gag reflex is present
How are oropharyngeal airways sized?
Measuring distance between anterior nares and tragus of ear
What is the problem with airway adjuncts that are too small?
May be ineffective
What is the problem with airway adjuncts that are too large?
May cause laryngospasm
What is often tolerated better than an oropharyngeal airway?
A nasopharyngeal airway
What complication may arise from insertion of a nasopharyngeal airway?
Haemorrhage from the vascular nasal mucosa
What is the effect of haemorrhage from vascular nasal mucosa caused by nasopharyngeal airway?
Worsens airway obstruction
When is a nasopharyngeal airway contraindicated?
Basal skull fracture
What is a laryngeal mask airway?
A device for supporting and maintaining the airway without tracheal intubation
Where does a laryngeal mask airway sit?
In the hypopharynx, covering the supraglottic structures
What is the result of a laryngeal mask airway covering the supraglottic structures?
It allows relaxation of the trachea
What is a laryngeal mask airway helpful for in the emergency setting?
Airway obstruction caused by supra-glottic airway abnormalities, or if bag-mask ventilation is not possible
What is the limitation of a laryngeal mask airway?
It does not totally protect the airway from aspiration of the stomach contents, and with high pressure ventilation, gastric distention may occur
In who might endotracheal intubation be difficult?
Infants
What should endotracheal intubation be preceded by?
Induction of anaesthesia (unless child unconscious)
What is involved in induction of anaesthesia before endotracheal intubation?
Drugs for sedation and neuromuscular blockade
What clues might suggest a child has a difficult airway?
- Presentation with airway obstruction or stridor
- Airway swelling or oedema
- History of obstructive sleep apnoea
- Syndromes with facial malformations
- History of previous difficult endotracheal intubation
Give 2 causes of airway swelling or oedema
- Burns
- Anaphylaxis
Give 3 facial malformations that might indicate a difficult airway
- Short mandible
- Ear deformity
- Pierre Robin syndrome
Who should be present during intubation when a difficult airway is suspected?
Senior anaesthetist and ENT surgeon
Describe the epiglottis in infants?
It is horse shoe shaped and relatively large
How does the larynx in infants differ to in older children?
In infants it is high anterior, at C2/3 compared to C5/6 in older children
What kind of laryngoscope is more commonly used in infants?
Straight blade (Miller blade)
Where is the laryngoscope positioned in infants?
Posterior to the epiglottis
What is done to the epiglottis when intubating an infant?
The epiglottis is lifted to allow visualisation of the glottis and vocal folds
What kind of laryngoscope is used in children and adults?
Curved blade (Macintosh)
Where is the laryngoscope positioned in children?
In the vallecula, anterior to the epiglottis
What is done to the epiglottis when intubating a child?
It is lifted to visualise the larynx
How are endotracheal tubes sized?
By internal diameter in mm
What is the narrowest party of the airway until age 12?
The level of the cricoid cartilage
What is the relevance of the cricoid cartilage being the narrowest part of the airway until age 12?
An endotracheal tube that passes easily through the vocal cords may still be too large to pass through the cricoid ring
What might the consequence be of an endotracheal tube that is too tight at the level of the cricoid?
May damage the mucosa
What might result from mucosal damage at the cricoid ring from a ET tube that is too late?
Airway oedema and post-extubation stridor
Rarely, tracheal scaring and stenosis
Can ET tubes with cuffs be safely used in infants and young children?
Yes, providing correct tube size is used, tube position verified, and cuff inflation pressure checked and limited
What is the result of ET tubes with cuffs now being confirmed to be safe to use in infants and young children?
They are first choice in paediatric critical care, and preferred in children with poor lung compliance or high airway resistance, or when precise ventilation and/or CO2 control is needed
When are uncuffed ET tubes used?
In newborn infants
