In the child with a compromised but functioning airway an important principle in all cases is to avoid worsening the situation by upsetting the child.
Crying and struggling may quickly convert a partially obstructed airway into a completely obstructed one. Administration of oxygen, nebulised epinephrine or the performance of a radiograph may all require skill. Parents’ help should be enlisted.
Partial obstruction from secretions/depressed conscious level
An airway partially obstructed by secretions should be cleared by suction as long as there is no stridor. The child with the stertorous breathing of partial obstruction due to a depressed conscious level or extreme fatigue is in danger of losing the airway completely.
The airway must be supported by a chin lift or jaw thrust manoeuvre and an anaesthetist asked to attend urgently. Consideration should be given to maintaining the airway with an oro-pharyngeal or naso-pharyngeal airway and the child may require intubation.
Croup syndromes
Patients with severe respiratory distress in association with harsh stridor and barking cough should be given nebulised epinephrine (5 ml of 1:1 000) with oxygen through a face mask. This will produce a transient improvement for 30–60 minutes but rarely alters the long-term course of the illness. This treatment should be given only to children with signs of severe obstruction. Epinephrine reduces the clinical severity of obstruction, but does not improve arterial blood gases, reduce the duration of hospitalization or the need for intubation. Children who have received epinephrine will appear improved for a short while only and need to be observed very closely with continuous ECG and oxygen saturation monitoring. They may later require tracheal intubation. A marked tachycardia is usually produced by the epinephrine, but other side effects are uncommon. This treatment is best used to “buy time” in which to assemble an experienced team to treat a child with severe croup.
Many children admitted to hospital with croup have hypoxaemia as a result of alveolar hypoventilation secondary to airways obstruction and ventilation perfusion imbalance.
The degree of hypoxaemia correlates poorly with clinical signs: the respiratory rate and the degree of sternal recession are the best clinical indicators. Humidified oxygen should be given through a face-mask, and, the oxygen saturation monitored. Oxygen saturation measurements are helpful in assessing severity and response to treatment but hypoventilation may be masked when the child is receiving high ambient oxygen. The oxygen saturation with the child breathing air should be checked intermittently.
Inhalation of warm moist air is widely used but is of unproven benefit.
Foreign body
Children with severe respiratory distress and a significant history of foreign body inhalation may require laryngoscopy if the “choking child” procedure has been unsuccessful. Do not jeopardise the airway by unpleasant or frightening interventions, but contact a senior anaesthetist/ENT surgeon urgently. However, in extreme cases of life threat immediate direct laryngoscopy with Magills forceps to remove a visible foreign body may be necessary.
Epiglottitis
Children with severe respiratory distress and a soft inspiratory stridor are candidates for epiglottitis. Intubation may be required. Contact a senior anaesthetist urgently. Do not jeopardise the airway by unpleasant or frightening interventions. The diagnosis of acute epiglottitis is made from the characteristic history and clinical findings. Lateral radiographs of the neck have been used to confirm the diagnosis, but these should be avoided as they disturb the child and have precipitated fatal total airway obstruction.
There is no evidence that nebulised epinephrine or steroids are beneficial. The child will need intubation after careful gaseous induction of anaesthesia. This must be done by an experienced anaesthetist unless there has been a respiratory arrest. When deeply anaesthetised the child can be laid on his back to allow laryngoscopy and intubation.
Tracheal intubation may be difficult because of the intense swelling and inflammation of the epiglottis (“cherry red epiglottis”). A much smaller tube than the one usually required for the child’s size will be necessary.
Anaphylaxis
In addition to oxygen, the specific treatment for anaphylaxis is intramuscular epinephrine (10 micrograms/kg). Nebulised adrenaline as described above in the treatment of croup may also be given (see also page 107).
Further treatment for upper airway conditions Croup
There is now good evidence that steroids modify the natural history of croup.
Children with mild, moderate or severe croup can benefit from steroid treatment.
Current treatments are either systemic dexamethasone 0·15 mg/kg or inhaled nebulised budenoside 1 milligram. Dexamethasone can be continued once daily for two to three days if symptoms persist and budenoside may be repeated 30–60 minutes later if clinically indicated. Budenoside and dexamethasone are equally effective. The choice will depend on which route is most appropriate for the individual child but oral dexamethasone is the treatment of choice. The use of steroids in croup gives rise to some clinical improvement within hours and may lead to a reduction in hospital stay.
Fewer than 5% of children admitted to hospital with croup require tracheal intubation. The decision to intubate is a clinical one based on increasing tachycardia, tachypnoea and chest retraction, or the appearance of cyanosis, exhaustion or confusion.
Ideally, the procedure should be performed under general anaesthetic by an experienced paediatric anaesthetist, unless there has been a respiratory arrest. A much smaller gauge tracheal tube than usual is often required. If there is doubt about the diagnosis, or difficulty in intubation is anticipated, an ENT surgeon capable of performing a tracheotomy should be present.The median duration of intubation in croup is 3 days:
the younger the child, the longer intubation is usually required. Prednisolone (1 mg/kg every 12 hours) reduces the duration of intubation and the need for re-intubation in children with severe croup. All intubated children must have continuous CO2and SaO2 monitoring.
Over 80% of children with the rarer bacterial tracheitis need intubation and
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ventilatory support to maintain an adequate airway, as well as intravenous antibiotics (combination of flucloxacillin and cefotaxime).
Epiglottitis
This is now a rare condition in countries where HiB immunisation has been introduced. However, it does still occur, in an older age group, in cases of vaccine failure and in unimmunised children. Once the airway has been secured, blood should be sent for culture and treatment with intravenous cefotaxime or ceftriaxone commenced. With appropriate treatment, most children can be extubated after 24–36 hours and have recovered fully within 3–5 days. Complications such as hypoxic cerebral damage, pulmonary oedema and other serious Haemophilus infections are rare but in the under two year old, immunity is not secure and there are cases of secondary HiB meningitis occurring after successful treatment of epiglottitis. In countries where the HiB vaccine is in use there should be an investigation into vaccine failure.
Foreign body
In the case of the stridulous child with a relatively stable airway and a strong suspicion of foreign body inhalation, careful gaseous induction of anaesthesia should be induced by an experienced anaesthetist, with the presence of an ENT surgeon to perform a tracheotomy in case of disaster. The foreign body can then be removed under controlled conditions. In some cases, prior to anaesthesia, it may be appropriate to perform a careful lateral neck radiograph in the emergency room (taking extreme care not to distress the child, thus provoking complete obstruction) to ascertain the position and nature of the object.
Anaphylaxis
If there has not been significant improvement with the initial dose of epinephrine, a furthur intramuscular dose can be given after five minutes. Chlorpheniramine and steroids are also given to patients with anaphylaxis but their onset of action (if any) is delayed (see page 109).
Background information on conditions causing acute upper airway obstruction
Most cases of upper airway obstruction in children are the result of infection, but inhalation of a foreign body or hot gases (house fires), angioneurotic oedema and trauma can all result in obstruction and the normal airway will become obstructed in the unconscious, supine patient.
Croup
Croup is defined as an acute clinical syndrome with inspiratory stridor, a barking cough, hoarseness and variable degrees of respiratory distress. This definition embraces several distinct disorders. Acute viral laryngotracheobronchitis (viral croup) is the commonest form of croup and accounts for over 95% of laryngotracheal infections.
Parainfluenza viruses are the commonest pathogens but other respiratory viruses, such as respiratory syncytial virus and adenoviruses produce a similar clinical picture. The peak incidence of viral croup is in the second year of life and most hospital admissions are in children aged between 6 months and five years.
The typical features of a barking cough, harsh stridor and hoarseness are usually preceded by fever and coryza for 1–3 days. The symptoms often start, and are worse, at night. Many children have stridor and a mild fever (<38·5º C), with little or no
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respiratory difficulty. If tracheal narrowing is minor, stridor will be present only when the child hyperventilates or is upset. As the narrowing progresses, the stridor becomes both inspiratory and expiratory and is present even when the child is at rest. Some children, and particularly those below the age of three, develop the features of increasing obstruction and hypoxaemia with marked sternal and subcostal recession, tachycardia, tachypnoea and agitation. If the infection extends distally to the bronchi, wheeze may also be audible.
Some children have repeated episodes of croup without preceding fever and coryza.
The symptoms are often of sudden onset at night, and usually persist for only a few hours. This recurrent or spasmodic croup is often associated with atopic disease (asthma, eczema, hay-fever). The episodes can be severe, but are more commonly self-limiting. They are difficult to distinguish clinically from infectious croup and appear to respond identically to treatment.
Bacterial tracheitis, or pseudomembranous croup, is an uncommon but life-threatening form of croup. Infection of the tracheal mucosa with Staphyloccocus aureus, streptococci or Haemophilus influenzae B (HiB) results in copious, purulent secretions and mucosal necrosis. The child appears toxic with a high fever and the signs of progressive upper airway obstruction. The croupy cough and the absence of drooling helps distinguish this condition from epiglottitis. Over 80% of children with this illness need intubation and ventilatory support to maintain an adequate airway, as well as intravenous antibiotics (combination of flucloxacillin and cefotaxime).
Acute epiglottitis
Acute epiglottitis shares many clinical features with croup but it is a quite distinct entity. Although much less common than croup, its importance is that unless the diagnosis is made rapidly and appropriate treatment commenced, total obstruction and death are likely to ensue. In countries where routine immunisation of infants with the conjugate vaccine against HiB has been introduced, there has been a dramatic reduction in the incidence of epiglottitis.
Infection with Haemophilus influenzae B causes intense swelling of the epiglottis and the surrounding tissues and obstruction of the larynx. Epiglottitis is most common in children aged 1–6 years, but it can occur in infants and in adults.
The onset of the illness is usually acute with high fever, lethargy, a soft inspiratory stridor and rapidly increasing respiratory difficulty over 3–6 hours. In contrast to croup, cough is minimal or absent. Typically the child sits immobile, with the chin slightly raised and the mouth open, drooling saliva. He looks very toxic, pale and has poor peripheral circulation (most are septicaemic). There is usually a high fever (939⬚C).
Because the throat is so painful, the child is reluctant to speak and unable to swallow drinks or saliva. Disturbance of the child, and particularly attempts to lie the child down, to examine the throat with a spatula, or to insert an intravenous cannula, can precipitate total obstruction and death, and must be avoided.
Other causes of upper airways obstruction
Although croup accounts for the large majority of cases of acute upper airways obstruction, several other uncommon conditions need to be considered in the differential diagnosis. Diphtheria is seen only in children who have not been immunised against the disease. Always ask about immunisations in any child with fever and the signs of upper airways obstruction, particularly if they have been to endemic areas recently.
Marked tonsillar swelling in infectious mononucleosis or acute tonsillitis can rarely compromise the upper airway. The passage of a nasopharyngeal tube may give instant
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relief. Retropharyngeal abscess is uncommon nowadays, but can present with fever and the features of upper airway obstruction together with feeding difficulties. Treatment is by surgical drainage and intravenous antibiotics.
Anaphylaxis is a potentially life-threatening immunologically mediated syndrome in which laryngeal oedema can develop over minutes often with swelling (angioneurotic oedema) of the face, mouth and tongue. Food allergies, especially nuts and drug reactions, especially contrast media and anaesthetic drugs are usual causes of this.
Prodromal symptoms of flushing, itching, facial swelling and urticaria usually precede stridor. Abdominal pain, diarrhoea, wheeze and shock may be additional or alternative manifestations of anaphylaxis (page 108).
A severe episode of anaphylaxis can be predicted in patients with a previous severe episode or a history of increasingly severe reaction, a history of asthma or treatment with beta blockers.
The inquisitive and fearless toddler and the infant with toddler siblings is at risk of inhaling a foreign body. If an inhaled foreign body lodges in the larynx or trachea, the outcome is often fatal at home, unless measures such as those discussed in Chapter 4 are performed. Should a child present to hospital, especially during waking hours, with very sudden onset of stridor and other signs of acute upper airway obstruction, and particularly if there is no fever or preceding illness, then a laryngeal foreign body is the likely diagnosis. A history of eating or of playing with small objects immediately prior to the onset of symptoms is strong supportive evidence. Foodstuffs (nuts, sweets, meat) are the commonest offending items. In 1998 16 children in England and Wales died from choking. In all but one food was the cause of obstruction. In some instances, objects may compress the trachea from their position of lodgement in the upper oesophagus producing a similar but less severe picture of airway obstruction.
The object may pass through the larynx into the bronchial tree, where it produces a persistent cough of very acute onset, and unilateral wheezing. Examination of the chest may reveal decreased air entry on one side or evidence of a collapsed lung. Inspiratory and expiratory chest radiographs may show mediastinal shift on expiration due to gas-trapping distal to the bronchial foreign body. Removal through a bronchoscope under general anaesthetic should be performed as soon as possible as there is a risk of coughing moving the object into the trachea and causing life-threatening obstruction.