In the first 18 months of life, laryngomalacia is a common cause of chronic stridor. This condition gradually resolves in most cases, as the airway enlarges and the cartilaginous tracheal rings gain strength. The most common cause of acute stridor in children is viral laryngotracheobronchitis (croup). Viral croup peaks in autumn or spring, but can occur anytime of year and usually due to outbreaks of parainfluenza (I and II), Enterovirus, Adenovirus, or RSV outbreaks. The patient is classically between six months and 6 years old and presents, often towards sundown, with a sea-lion cough with or without stridor. The history is usually sufficient to make the diagnosis and the examination is to assess severity and exclude other causes. If the history is suggestive, a throat examination is best avoided for fear of provoking the laryngeal oedema and triggering a critical airway scenario. leave the child on the parents lap, approach them gently, check their chest and treat them.
- Respiratory rate:
- Infant: 25-40
- 1-5 Years: 20-30
- > 6 Years: 15-25
- accessory muscles
- nasal flaring
- chest recession: suprasternal, intercostal, subcostal
- chest shape
- tracheal deviation
- apex impulse
- chest expansion
- ominous signs:
- restlessness / drowsiness: hypoxia / hypercapnia
- cyanosis
Nebulised adrenaline can be used as a temporising measure for sever croup:
- 0.5 mL / kg of 1: 1,000 (1 mg/mL) adrenaline made up to at least 4 mL with Normal Saline
- maximum 5 mL adrenaline
- otherwise, consider 0.01 mL/kg intramuscular 1:1000 Adrenaline to upper / outer thigh
Peak effect of nebulised adrenaline is seen at ∼ 10 minutes, with sustained effect until 30 min before gradual return to baseline by 120 min. NNT = 17 to prevent reattendance (let alone admission). Nebulised adrenaline is associated both with a reduction in rates of intubation and re-intubation, as well as reduction in ICU admission rates. Consider Tausig or Wesley Croup scores.
Corticosteroids are the cornerstone of treatment for croup. The effects of steroids can be seen within 6 hours of administration (perhaps as early as 2 hours). Oral steroids works just as well intramuscular steroids. Any of the following steroids may be used. Dexamethasone is often preferred for its longer half-life allowing a one-off dose but prednisolone is often more readily available.
- dexamethasone [8 mg/2mL solution]: 0.15 mg / kg (max 10 mg) PO (or IMI) statim ± a second dose 18 hours later
- effect usually last 2-4 days
- prednisolone [5mg/mL solution]: 1 mg / kg (max 50 mg) PO once daily x 2 days
- prednisone often needs a second dose 24 hours later
- budesonide: 2 mg nebulised
A patient given steroids and watched more than 3 hours after adrenaline whose social circumstances allow and without stridor at rest can go home.
If the airway is completely inadequate, consider:
- Surgical cricothyroidotomy (> 12 years)
- Needle cricothyroidotomy (any age; may be used to gain time for/during surgical cricothyroidotomy)
Needle Cricothyroidotomy
Passing an over-the-needle catheter through the cricothyroid membrane provides a temporary secure airway to oxygenate and ventilate a patient in severe respiratory distress in whom less invasive techniques (eg, bag-valve-mask ventilation, laryngeal mask ventilation, endotracheal intubation) have failed or are not likely to be successful (i.e., a “can’t intubate, can’t ventilate” scenario):¹
- 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)
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.²
(Mean cricothyroid membrane height in adults is 8 mm in males and 6 mm in females; suggesting that catheters up to 13-gauge can be safely used in a patient with a fully developed airway. The neonatal cricothyroid membrane is probably 2-3 mm in height.)¹
Surface markings: the cricothyroid membrane is the horizontal gap between thyroid cartilage (Adam’s apple) above and horizontal cricoid cartilage below.
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.
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.²
Management of Croup
- Budesonide 2 mg (in 2 mL N/Saline) Nebulised or Dexamethasone 0.15 mg/kg Orally
- Adrenaline 1:1,000 0.5 mL/kg nebulised is an effective, albeit temporising, measure.
Five commonest causes of acute stridor in children (and their differentiating features):
- inhaled foreign body: eating, choking, gagging
- anaphylaxis: cutaneous and gastrointestinal manifestations, usually temporally related to a food, drug, or insect sting
- croup: barky (‘sea-lion’) cough with diurnal variation
- epiglottitis: toxic, drooling child
- bacterial tracheitis: toxic, non-drooling child
(Burns might be number six on the list).
A history of choking is the most reliable predictor of foreign body aspiration/inhalation and should prompt further evaluation and consideration for bronchoscopy.
Management of Foreign Body Aspiration
- Alert / Able to maintain airway → supplemental oxygen and leave in a position of comfort until more help arrives
- Complete Airway Obstruction
- Infant (< 1 year old) → 5 x back blows then 5 x chest thrusts
- Child (≥ 1 year old) → abdominal thrusts
- If BLS manoeuvres fail → Bag & Mask Ventilation
- If no chest rise with BVM ventilation → Laryngoscopy to remove FB with paediatric Magill forceps
- If airway obstruction persists → consider intubation, cricothyrotomy, tracheostomy, or Heliox
Radiography
Steeple sign (croup)
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| [Wikimedia Commons] |
Thumb print sign (epiglottitis)
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| [Paediatric Imaging, Wikispaces] |
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| [Wikimedia Commons] |
Airway foreign bodies (Radiopaedia)
Complications of needle cricothyroidotomy:
- Asphyxia
- Aspiration
- Cellulitis
- Oesophageal perforation
- Haemorrhage
- Haematoma
- Posterior tracheal wall perforation
- Subcutaneous and/or mediastinal emphysema
- Thyroid perforation
- Inadequate ventilation leading to hypoxia and death²
References
- Needle cricothyroidotomy with percutaneous transtracheal ventilation, UpToDate
- Airway procedures. The Royal Children’s Hospital Melbourne
- Pedscases.com
Further Reading
- Leung A, Cho H. Diagnosis of Stridor in Children. American Family Physician, 1999 Nov 15;60(8):2289-2296.
- Airway Foreign Body Imaging – Medscape
