Total Airway Obstruction by Papillomas During Induction of General Anesthesia

Recurrent respiratory papillomatosis is an increasingly common viral infection of children caused by the human papilloma virus [1]. Progressive formation of multiple papillomas in the respiratory tract requires surgical removal to prevent speech difficulties and respiratory compromise. Patients are commonly diagnosed with change in voice or hoarseness prior to the development of severe respiratory compromise [2,3]. We present a case of complete airway obstruction during induction of general anesthesia in which the usual signs of severe respiratory compromise (including difficulty clearing secretions, sleep disturbances, decreased activity, and difficulty eating) were not present preoperatively. Case Report A 1.5-yr-old boy presented as a day surgery admit for CO2 ablation of laryngeal papillomas. He had been seen by his pediatrician for inspiratory airway noise and had been treated (as an outpatient) with antibiotics for "croup" and bronchodilators for "asthma" prior to being diagnosed with laryngeal papillomatosis. The patient had no history of decreased activity or breathing difficulties during sleep. He had an occasional coughing episode during eating that quickly resolved with a sip of water, but he had not required a change in diet. On physical examination, he had mild inspiratory stridor but was otherwise alert with normal activity and no evidence of respiratory difficulty or distress. Preoperative lateral radiographs of the neck revealed a mass in the posterior pharynx that did not obstruct the airway. Indirect laryngoscopy revealed one large papilloma on the epiglottis and arytenoids and several small ones around the laryngeal inlet. On the day of surgery, the patient was sedated preoperatively with 0.3 mg/kg midazolam orally 45 min before the procedure. He was taken to the operating room awake, calm, and cooperative. Routine monitors were applied, and general anesthesia was induced via a face mask with 70% nitrous oxide, 30% oxygen, and incrementally increased halothane concentrations with the patient in the sitting position. The patient remained calm and cooperative during induction of anesthesia, and spontaneous ventilation was maintained. After the patient was positioned supine, partial airway obstruction occurred, which improved with positive pressure support. Spontaneous ventilation was continued with pressure support. Several minutes later, complete obstruction of the airway occurred. Succinylcholine (1 mg/kg) and atropine (0.1 mg) were given intravenously (IV). Visualization of the posterior pharynx by direct laryngoscopy revealed a mass of papillomas completely occluding the airway. Placement of the endotracheal tube was abandoned, and rigid bronchoscopy was attempted by the otolaryngologist. On rigid bronchoscopy, the mass of papillomas precluded advancement of the rigid bronchoscope. An emergency tracheostomy was performed, and a 4.5 uncuffed endotracheal tube placed into the tracheostomy site. Total duration of desaturation (i.e., < 95%) was approximately 8 min, and saturation < 50% was < 5 min. Bradycardia and hypotension did not develop during the period of desaturation. After placement of the tracheostomy and return of oxygen saturation to 100%, rigid bronchoscopy was performed and photographs were taken (Figure 1). The case proceeded uneventfully, and the patient was taken to the recovery room postoperatively awake but sedated. When he was completely awake, a neurologic examination was performed and was completely normal. The patient returned to the operating room for a second look 2 wk later. Both the vocal cords and posterior pharynx were normal at that time (Figure 2).Figure 1: Total obstruction of the vocal cords by papillomas as seen on direct laryngoscopy.Figure 2: Normal airway seen 2 wk postoperatively by direct laryngoscopy.Discussion Recurrent respiratory papillomatosis was first described by MacKenzie in 1880 as a disease of the larynx confined to children [4], but subsequent studies have identified this disease in adults as well [5]. It is caused by infection of the mucous membranes with the human papilloma virus types 6 and 11 [1]. It was originally thought to be transmitted to the child during birth from maternal genital warts; however, there are numerous cases where this history is not present [1,2]. Several studies [6,7] suggest that abnormal immune systems with subnormal killer cell activity and decreased T-lymphocyte counts are necessary for contraction of this disease. The initial presentation of this disease is variable and often mistaken for asthma, bronchitis, croup, or laryngomalacia [3]. The most common symptoms are a change in voice, hoarseness, or stridor, usually prior to the development of significant respiratory difficulty [2,3]. Papillomas are typically located near the vocal cords but may also be found on the palate, tonsils, and epiglottis. Extension of the papillomas into the subglottic region is common (35% of the pediatric cases and 43% of the adult cases), but extension into the trachea or proximal bronchi is rare (2%-5%) [5,8]. Lung involvement, while also rare (<1%), is often fatal [3,9]. The clinical course of this disease includes multiple recurrences after all modes of therapy. In most cases, spontaneous remissions do not occur, and the disease can continue well into adult life [2]. Death from recurrent respiratory papillomatosis, although rare, is most commonly due to surgical complications, airway obstruction with seeding of the distal trachea and lung, or malignant transformation [3]. Until remission of the disease, the mainstay of therapy is surgical excision of the papillomas. Prior to the use of the CO2 laser, electrocautery, suction diathermy, and cryotherapy were used [3,10]. Although effective at removing the papillomas, the extensive use of these techniques lead to marked scar formation and airway stenosis [3,10]. CO2 laser ablation, while not a cure, is the current treatment of choice [3,10,11]. Postoperative complications including airway stenosis, webbing, scarring, and granulation formation can occur, but with less severity than older techniques [11,12]. Less common complications include tracheal perforation, tracheoesophageal fistula, bronchitis, pneumonia, pneumothorax, hemorrhage, respiratory arrest, and death [5,13]. Wegrzynowicz et al. [14] noted an unusual complication. Burning vapors created by ignition of the surgeon's gloves were inhaled around the laryngoscope then exhaled through the nose, causing ignition of the patient's mustache [14]. Numerous medical therapies have been tried to slow the rate of papilloma growth, including interferon [15,16], acyclovir [17,18], riboviron [19], and cabbage juice [3], all with limited success. Abramson et al. [20] combined preoperative IV dihematoporphyrin with argon pump dye laser phototherapy and noted a 50% reduction in the papilloma growth rate. Addition of this mode of therapy to CO2 ablation may decrease the perioperative risks of airway complications due to a decrease in the size of the lesions, but it will probably not reduce long-term complications as the recurrence rate was not affected [20]. A variety of anesthetic techniques have been successfully used with these patients. General anesthesia is often induced by incremental inhalation of halothane, nitrous oxide, and oxygen [21,22]. However, both IV thiopental and intramuscular ketamine inductions have been used without complications [21,22]. Whether to maintain spontaneous ventilation or use muscle relaxants has been a controversial issue for more than a decade. Spontaneous ventilation is advocated to reduce the risk of airway fires and the incidence of postoperative croup. Periods of CO2 laser ablation are alternated with supplemental oxygenation by mask or temporary placement of a small endotracheal tube. Muscle relaxants, while used routinely in the past without complications [21], are often avoided because of the concern that relaxation of the posterior pharyngeal muscles will lead to airway obstruction by pedunculated masses. However, since relaxation of these same muscles occurs with surgical planes of inhaled anesthesia even with spontaneous ventilation, airway obstruction may still occur. Additionally, the use of muscle relaxants after total airway obstruction may relieve superimposed laryngospasm improving ventilation, avoid postobstructive pulmonary edema, and prevent further traction of the mass into the airway by inspiratory efforts. Tracheostomy, while used in up to 61% of patients in the past [1,2,21], is currently reserved for total airway obstruction when ventilation and intubation are not possible [21]. Administration of local anesthetics to lessen the risk of laryngospasm is also common [21]. Topical application is ineffective, because resection of the papillomas leaves areas of denuded tissue that are not anesthetized [22]. Lawson et al. [22] used a continuous infusion of procaine (1 mg [[centered dot]] kg-1 [[centered dot]] min-1), which produced blunting of the cough reflexes without the toxic reactions or delayed emergence seen with lidocaine [22]. Unfortunately, occasional respiratory depression, including apnea, occurred, which makes this technique less than ideal [22]. Perioperative nebulized racemic epinephrine and IV steroids have been used to prevent and treat postoperative croup [23]. While the efficacy of racemic epinephrine is well known, the usefulness of steroids remains controversial. Forestner et al. [21] studied the incidence of croup with and without intraoperative steroid administration. Although there was no statistical difference between the groups, they recommended the use of steroids because they cause few adverse reactions and may potentially be beneficial [21]. In summary, it appears that a variety of anesthetic techniques can be used on these patients successfully. Preoperative planning between the otolaryngologist and the anesthesiologist is essential for optimal care of the patient. It is important to be prepared for an emergency tracheostomy at all times when conducting a general anesthetic on these patients, even when severe preoperative airway compromise is not present, as is illustrated by this case.