INFECTIOUS CROUP, FOREIGN BODY ASPIRATION, & ACUTE EPIGLOTTITIS
Croup is obstruction of the airway characterized by a barking cough. One type of croup, postintubation croup, has already been discussed. Another type is due to viral infection. Infectious croup usually fol-lows a viral URI in children aged 3 months to 3 years. The airway below the epiglottis is involved (laryn-gotracheobronchitis). Infectious croup progresses slowly and rarely requires intubation. Foreign body aspiration is typically encountered in children aged 6 months to 5 years. Commonly aspirated objects include peanuts, coins, screws, nails, tacks, and small pieces of toys. Onset is typically acute and the obstruction may be supraglottic, glottic, or subglot-tic. Stridor is prominent with the first two, whereas wheezing is more common with the latter. A clear history of an aspiration may be absent. Acute epi-glottitis is a bacterial infection (most commonlyHaemophilus influenzae type B) classically affect-ing 2- to 6-year-old children but also occasionally appearing in older children and adults. It rapidly progresses from a sore throat to dysphagia and com-plete airway obstruction. The term supraglottitis has been suggested because the inflammation typically involves all supraglottic structures. Endotracheal intubation and antibiotic therapy can be lifesaving. Epiglottitis has increasingly become a disease of adults because of the widespread use of H influenza vaccines in children.
Patients with croup are managed conservatively with oxygen and mist therapy. Nebulized racemic epinephrine (0.5 mL of a 2.25% solution in 2.5 mL normal saline) and intravenous dexamethasone (0.25–0.5 mg/kg) are used. Indications for intuba-tion include progressive intercostal retractions, obvious respiratory fatigue, and central cyanosis.
Anesthetic management of a foreign body aspiration is challenging, particularly with supra-glottic and glottic obstruction. Minor manipula-tion of the airway can convert partial into complete obstruction. Experts recommend careful inhala-tional induction for a supraglottic object and gen-tle upper airway endoscopy to remove the object, secure the airway, or both. When the object is subglottic, a rapid-sequence or inhalational induc-tion is usually followed by rigid bronchoscopy by the surgeon or endotracheal intubation and flex-ible bronchoscopy. Surgical preferences may vary according to the size of the patient and the nature and location of the foreign body. Close coopera-tion between the surgeon and anesthesiologist is essential.
Children with impending airway obstruction from epiglottitis present in the operating room for definitive diagnosis by laryngoscopy followed by intubation. A preoperative lateral neck radiograph may show a characteristic thumblike epiglottic shadow, which is very specific but often absent. The radiograph is also helpful in revealing other causes of obstruction, such as foreign bodies. Stridor, drooling, hoarseness, rapid onset and progression, tachypnea, chest retractions, and a preference for the upright position are predictive of airway obstruc-tion. Total obstruction can occur at any moment, and adequate preparations for a possible tracheos-tomy must be made prior to induction of general anesthesia. Laryngoscopy should not be performed before induction of anesthesia because of the possi-bility of laryngospasm. In most cases, an inhalational induction is performed with the patient in the sit-ting position, using a volatile anesthetic and oxygen. Oral intubation with an endotracheal tube one half to one size smaller than usual is attempted as soon as an adequate depth of anesthesia is established. The oral tube may be replaced with a well-secured nasal endotracheal tube at the end of the procedure, as the latter is better tolerated in the postoperative period. If intubation is impossible, rigid bronchoscopy or emergency tracheostomy must be performed.