Airway Obstruction in Infants and Children

Upper airway obstruction in children is dangerous and may progress rapidly. It is essential to make a firm diagnosis and take the appropriate action without delay. 139 SIGNS OF AIRWAY OBSTRUCTION 1 Stertor is the noise produced by obstruction in the throat, i.e. above the larynx, and is usually a low-pitched choking type of noise. 2 Stridor is a high-pitched sound produced by narrowing within the more rigid confines of the larynx or trachea. In laryngeal obstruction the stridor is inspiratory; in tracheal lesions it is usually both inspiratory and expiratory. 3 Use of accessory muscles of respiration. 4 Pallor, sweating and restlessness. 5 Tachycardia. 6 Cyanosis. It is important to examine the child in adequate lighting, preferably daylight.The lips particularly will show the dusky coloration, which may be very subtle. 7 Intercostal and sternal recession (Fig. 37.1).The sternum may be sucked in almost to the vertebrae in the child’s attempts to breathe. 8 Exhaustion—a late stage in asphyxia,which should be avoided.The child makes less effort to breathe, stridor and insuction become less pronounced and apnoea is not far off. Box 37.1 Signs of airway obstruction. Management of airway obstruction The management of airway insufficiency always depends on the severity of the obstruction, and severe obstruction necessitates immediate airway support by oxygen, endotracheal intubation or even tracheostomy. If time and the child’s condition allow, every child with stridor should have a PA chest X-ray and a lateral soft-tissue film of the neck, which will show the larynx and upper trachea clearly. If a vascular ring or tracheooesophageal fistula is suspected, a barium swallow is a necessary investigation Neonates may be intubated without the need for general anaesthesia but great care must be taken not to damage the larynx and cause further obstruction from haematoma or oedema. Older children, unless so anoxic as to be unconscious, will require general anaesthesia for intubation, and at the same time the larynx, trachea and bronchi should be inspected. The diagnosis is then usually apparent and further management can be directed appropriately. LARYNGOSCOPY AND BRONCHOSCOPY Inspection of the airways in cases of respiratory obstruction calls for the highest degree of cooperation between surgeon and anaesthetist. The larynx is inspected under deep anaesthesia using a rigid paediatric laryngoscope and Hopkins rod telescope (Fig. 37.2). An anaesthetic type laryngoscope usually gives an inadequate view owing to its poorer lighting. Bronchoscopy in babies and children has been facilitated greatly by the introduction of ventilating bronchoscopes, which allow coupling to a Tpiece anaesthetic circuit and at the same time provide superb vision through a rod-lens telescope system (Fig. 37.3). A side channel allows for instrumentation and suction. Using this type of bronchoscope, the airways of even small premature babies may be examined with a much greater degree of precision and safety than is possible with the older type open bronchoscope tube. Causes of upper airway obstruction in infancy SUPRA LARYNGEAL CAUSES Choanal atresia Failure of posterior canalization of the nasal airways results in severe neonatal airway obstruction, which is relieved by crying. Surgical correction will be required. Micrognathia Underdevelopment of the mandible as in Pierre Robin syndrome or Treacher–Collins syndrome results in posterior displacement of the tongue and oropharyngeal obstruction.The neonate may asphyxiate unless corrective measures are taken. Adeno-tonsillar hypertrophy Large tonsils and adenoids may occlude the naso-oro-pharyngeal airway to a serious degree, especially during sleep. This may result in obstructive apnoea during sleep, with loud snoring punctuated by periods of silence followed by a large gasp. If not recognized and treated, right heart failure may ensue. LARYNGEAL CAUSES Congenital Laryngomalacia (Fig. 37.4) The stridor starts at or shortly after birth and is due to inward collapse of the soft laryngeal tissues on inspiration. It usually resolves by the age of 2 or 3 years, but meanwhile the baby may have real respiratory difficulties. Diagnosis is confirmed by laryngoscopy without intubation when the supraglottic collapse is seen on inspiration. It can be relieved by division or excision of the aryepiglottic folds. Congenital subglottic stenosis This occurs at the level of the cricoid cartilage.There will be stridor from birth and the stenosis may be visible on a lateral X-ray of the neck. Diagnosis is confirmed by laryngoscopy. Laryngeal webs Laryngeal webs are anteriorly situated (Fig. 37.5) and if large can cause severe stridor and obstruction.The most extreme degree of webbing, atresia, is fatal unless immediate tracheostomy is performed. Laryngeal cysts Laryngeal cysts may be congenital or may be the result of endotracheal intubation. They may cause variable airway obstruction, often dependent on position. Vascular ring A vascular ring developmental anomaly of the aorta—surrounds the oesophagus and trachea, causing constriction. Diagnosis is made by barium swallow and angiography, and the treatment is by surgery to divide the vascular ring. Acquired Foreign body (Figs 37.6 and 37.7) The sudden onset of stridor in a formerly normal child must always be regarded as being due to a foreign body until proved otherwise. A history of choking and coughing, especially if while eating, should alert the attending doctor to the likelihood of aspiration; peanuts are particularly dangerous in this respect and should never be given to youngsters. Examination and chest X-rays may be entirely normal and the only way to exclude a foreign body in the bronchus is by bronchoscopy. A larger foreign body may lodge in the larynx and cause severe respiratory distress. It may be possible to remove it by the Heimlich manoeuvre (compression of the upper abdomen to raise intrathoracic pressure) but if this fails, endoscopy or tracheostomy will be necessary. Acute laryngitis,acute epiglottitis and laryngotracheobronchitis Described in Chapter 33. Subglottic stenosis (Fig. 37.8) Subglottic stenosis is now seen most commonly in low-birth-weight babies who have required prolonged ventilation by endotracheal tube, but may occur at any age from intubation or trauma.Treatment is highly specialized and entails some form of laryngotracheoplasty. Subglottic stenosis cannot always be avoided. Multiple laryngeal papillomata (Fig. 37.9) Multiple laryngeal papillomata should be suspected in a child with progressive hoarseness or aphonia and airway obstruction. There may be little stridor since the mass of papillomata is too soft to vibrate the air column. Diagnosis is by direct laryngoscopy, and removal of the papillomata is best accomplished using the carbon dioxide laser, which is very accurate and, if used carefully, causes least damage.The papillomata are of viral origin (HPV 6 or 11) and have a strong tendency to recur. NB. Any child with stridor is potentially at risk of dying from asphyxia and every case should be investigated to determine the cause. It is dangerous to believe that all children ‘grow out’ of a tendency to stridor.

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