Upper Airway Disease/Obstruction (upper airway obstruction, stridor, croup)

1. Description of the problem

Basic concepts and physiology

1. Poiseuille’s Law

2. Pediatric airway: Given that a decrease in radius size increases resistance significantly, children who have small airways to begin with are at risk of having a significant increase in airway resistance from even a small amount of swelling.

3. Upper airway narrowing produces changes in either inspiratory or expiratory flow depending on the location of the obstruction in the respiratory system. Extrathoracic lesions (those above the glottis) lead to inspiratory stridor; Intrathoracic lesions (below the level of the glottis) lead to expiratory stridor.

Stridor is the key distinctive respiratory finding. Additional findings consistent with respiratory distress may be evident as well—cyanosis, tachypnea, use of accessory muscles. The more agitated the patient the worse the symptoms, signs, and gas exchange.

Key management points

• Keep the child calm.

• Depending on the suspected etiology, give oral steroids as early as possible.

• Clinically evaluate airway function:

• Plain film of neck: Help identify static tracheal or bronchial lesions

• Fluoroscopy: Identify dynamic longitudinal airway events. Best appreciated in this axis.

• Computerized tomography: Best to identify dynamic cross-sectional airway events

• Virtual bronchoscopy: Best to identify gross observation of trachea and bronchus

Specific conditions and hallmark management points

Acquired

Epiglottitis:This is an airway emergency given rapid progression of disease and risk for total airway occlusion. Keep child calm. Generally the condition appears toxic. Consult otolaryngology and anesthesiology departments. Patient should be intubated in operating room as soon as possible to secure airway. Initiate steroids and antibiotics.

Croup: Keep child calm. Use oral steroids and racemic epinephrine nebulized. Children with persistent stridor at rest should be admitted to the hospital. If patient distressed, start heliox with high-flow nasal cannula and consider intubation

Bacterial tracheitis: generally toxic appearance at presentation

– Intubate early

– Likely have pneumonia along with tracheitis (50%)

– Anticipate need to suction copious amounts of thick tracheal secretions

– Racemic epinephrine and steroids have no well-established role

Congenital

Laryngomalacia:

– Keep patient calm.

– No Albuterol or racemic epinephrine (relaxing of smooth muscle worsens malacia)

– Consider pronging, particularly if patient has bronchomalacia as well.

– Refer to otolarygology and pulmonary departments for close follow-up.

– High risk for aspiration and gastroesophageal reflux

– Resolves with time (months)

Vascular Ring:

– Keep patient calm.

– Consider heliox.

– Diagnosis by barium swallow, bronchoscopy, or contrast computerized tomography of chest

– Treatment is surgery.

Subglottic stenosis:

– Keep child calm

– Oral Steroids

– Racemic epinephrine nebulized

– Heliox

– Consider intubating.

2. Emergency Management

• Calm patient, either though help of family or with sedation.

• Consider steroids and racemic epinephrine.

• If considering intubation, obtain tube size 1 and two sizes smaller than normal. Consider using lubrication on sides of endotracheal tube to facilitate passing through subglottic area. If available, consult otolaryngology department for support.

3. Diagnosis

Establishing the diagnosis

Classification of stridor will help identify location of lesion along with detailed history.

Classic patient with croup (primary acquired cause of stridor) wakes up in the middle of the night with severe distress, may or may not improve en route to the hospital, and has viral prodrome.

Children with subglottic stenosis likely have a history of prolonged intubation, prematurity, tracheostomy in the past, or traumatic intubation.

Lateral airway films can show a classic “steeple” sign for croup.

Please see Table I for a summary of infectious causes of upper airway obstruction.