Laryngomalacia (LM) is the most common congenital anomaly of the larynx (1), whereas vallecular cysts (VC) are a fairly uncommon but well recognized cause of upper airway obstruction and death in newborns and infants (2). LM associated with VC is very rare (3–6). Anesthetic management of the airway may be challenging, because these patients are at risk for sudden complete airway occlusion resulting in hypoventilation, hypoxemia, or death (7–9). We report six cases of concurrent VC and LM over a 4-yr period in Chang Gung Memorial Hospital and the problems encountered in airway management.
Table 1 gives a summary of six cases scheduled for marsupialization of VC and superglottoplasty under general anesthesia. Diagnosis of VC and LM was previously made on awake flexible bronchoscopy.
A 50-d-old infant, with a history of inspiratory stridor and difficult feeding, had suprasternal retractions and cyanosis while crying that did not respond to positional change. Computed tomography (CT) scan revealed a 2.5- × 2.5-cm midline VC. Because IV access was difficult, the decision was made to proceed with direct laryngoscopy and awake intubation. After preoxygenation, a Miller size 0 blade was inserted, but the infant struggled and became cyanotic. Laryngoscopy was aborted and anesthesia induced by inhaled halothane in 100% oxygen. The airway was maintained with some difficulty; atropine (0.02 mg/kg) and succinylcholine (2 mg/kg) were administered after IV access was obtained. Adequate mask ventilation was achieved only after hyperextension of the neck with the infant in the right lateral position. Repeat laryngoscopy revealed a large cyst obstructing the entire view with the blade in the midline. The blade was then slid to the left (45 degrees from the midline) and inserted laterally. With anterior-lateral neck pressure (right to left), the glottis was visualized and the endotracheal tube (ETT) inserted with the aid of an intubating stylet (Rüsch Soft-Tip™ Stylette Introducer, Rusch Inc, Duluth, GA).
A 105-d-old infant presented with a history of inspiratory stridor. In view of the small cyst size (0.8 × 0.8 cm) and comparatively mild symptoms, IV induction was performed with atropine (0.02 mg/kg), sodium thiopental (5 mg/kg), and succinylcholine (2 mg/kg). The airway was maintained without difficulty. A Miller size 0 laryngoscope blade was cautiously slid to the tongue base in the midline, and the cyst was noted in front of the tip of the blade. With the blade superficial to the vallecula, the glottis was visualized with backward, upward, and rightward pressure on the thyroid cartilage. An intubating stylet facilitated the ETT placement.
A 65-d-old infant (VC size estimated to be 1.5 × 1.5 cm) had a history of noisy breathing and cyanosis from birth. Anesthesia was induced with halothane in 100% oxygen. After IV access was secured, atropine (0.02 mg/kg) and succinylcholine (2 mg/kg) were administered. The ETT was passed, under right paraglossal laryngoscopy, with the aid of an intubating stylet.
A 53-d-old infant, with a history of stridor and respiratory distress during feeding, had noisy inspiratory effort and became cyanotic when crying. CT scan revealed a 1.0- × 1.0-cm VC. To maintain spontaneous respiration, the oropharynx was topicalized with 1 mL of 1% lidocaine, and anesthesia was induced with IV atropine (0.02 mg/kg) and ketamine (1 mg/kg). However, the infant struggled during laryngoscopy and became cyanotic. Because of difficult mask ventilation, succinylcholine (2 mg/kg) was administered, and laryngoscopy was attempted again. Unfortunately, neither the glottis nor epiglottis could be visualized. Considering the inability to maintain the airway and impossible positive-pressure ventilation by mask, the cyst was immediately punctured and aspirated. With subsequent decrease in cyst size, the glottis was visualized and the infant successfully intubated.
A 58-d-old infant presented with a history of poor feeding and respiratory distress from birth. CT scan showed a 1.0- × 1.0-cm VC. Awake nasal intubation with a fiberoptic bronchoscope (2.2-mm Olympus LF-P, Olympus Optical CO, Ltd, Garden City, NY) was attempted after oral topicalization with 1 mL of 1% lidocaine and nasal lidocaine jelly. Because of the limited oropharyngeal space and abnormal motion of the laryngeal structures, the architecture of the glottis could not be appreciated. The position of the bronchoscope had to be guided by transillumination through the neck. Bubbles could then be seen during expiration, and the bronchoscope was advanced in their direction intermittently during the expiratory phase of the infant’s respiration. After multiple attempts, normal tracheal structure was seen, and the ETT was advanced over the bronchoscope. Slight resistance was felt in the oropharynx, but with neck extension, jaw thrust, and a 1-cm withdrawal of the ETT, followed by clockwise rotation while advancing, the trachea was intubated.
A 42-d-old infant, with history of stridor and a 0.5- × 0.5-cm VC, underwent an awake nasal fiberoptic intubation performed uneventfully in a similar fashion as described in Case 5.
The infants remained postoperatively intubated for 24–48 h to allow adequate time for edema to subside and were tracheally extubated after satisfactory airway evaluation by the surgeon.
VCs cause airway obstruction both by mass effect in the hypopharynx and also by inferior and posterior displacement of the epiglottis, which may lead to supraglottic obstruction (9). This is particularly significant in LM where there may be (1) a flaccid epiglottis, (2) poorly supported arytenoids, or (3) short aryepiglottic folds (10). The airway collapse, contributed to by negative airway pressures as a result of the obstruction, is exacerbated during forceful inspiration (4). This may have occurred in Cases 1 and 4. Although ketamine preserves spontaneous respiration, laryngeal reflexes remain intact, and agitation/tachypnea may worsen airway obstruction (10).
Preoperative assessment of these patients should include a careful history targeted to identify situations or positions that worsen or improve obstructive symptoms. A neck CT scan should be obtained to determine cyst size, location, contents, and oropharyngeal topography to plan the optimal route of passage of the ETT or fiberoptic bronchoscope. A distinction should be made between solid tumors and cystic lesions because the latter may rupture or be deliberately aspirated in an emergency, as seen in Case 4. In this series, the location of the cyst and the degree of anatomical distortion imposed by LM were more important than cyst size in determining the difficulty of airway management (11).
We managed to secure the airway with direct laryngoscopy in four cases, but they were not uncomplicated. Even in experienced hands, direct laryngoscopy is fraught with dangers. These include (1) cyst rupture, which may lead to aspiration, and incomplete marsupialization (with subsequent cyst recurrence), (2) loss of airway, (3) patient agitation and forceful inspiration, which exacerbate airway collapse, (4) increase in cyst size because of manipulation or hemorrhage into the cyst from trauma, (5) edema, bleeding, and increased secretions from trauma to the oral mucosa. Nevertheless, anesthesiologists may still need to use this skill in an emergency. Our experience suggests that the use of paraglossal straight blade laryngoscopy (12), aided with an intubating stylet, will be most likely successful. A large bore needle (≥18-gauge) with an attached syringe should be available if emergency aspiration is required. The surgeon should be on hand to intervene with emergency tracheotomy (12). VC should preferably not be aspirated as a primary procedure because of the risk of pulmonary aspiration, increased recurrence rate, and difficulty in identifying the cyst margin on subsequent surgery.
Although maintaining spontaneous ventilation offers an element of safety in patients with threatening airways, we chose to use muscle relaxants for several reasons. From our experience with Case 1, we found that muscle relaxation actually improved mask ventilation and provided better conditions for laryngoscopy. Succinylcholine was used in the following three cases for those reasons, knowing that if we failed to secure the airway, we could always use mask ventilation and that emergency cyst aspiration would be easier to perform in a paralyzed patient.
Although fiberoptic intubation is considered one of the safest and most effective means to secure a difficult airway, we encountered several hurdles. First, the cyst occupied almost all the hypopharynx, leaving little room for manipulation. Second, the cyst caused severe distortion of the larynx and pushed the glottis to an unusually acute angle. This not only created an awkward passage for the bronchoscope, but also made it easy to flip out of the trachea during advancement of the ETT. Third, recognition of the larynx was tricky because of co-existing LM. Last, limitations in the volume of local anesthetic, imposed by toxicity guidelines, made adequate topicalization difficult. We also found that it was hard to locate the larynx via the midline because it was immediately behind the VC, and limited space prevented the bronchoscope from being flexed to such an acute angle. A lateral approach was simpler (right or left, depending on the neck CT) with more room to maneuver the bronchoscope. As the larynx appears laterally rather than in front of the lens, the bronchoscope has to be rotated while advancing and may be guided by viewing the transillumination of the neck similar to the principle used in light-wand techniques (13). The loss of normal laryngeal architecture compounds the difficulty in identifying the larynx, but emerging bubbles may give a hint. The bronchoscope should be advanced in the direction of the bubbles during expiration as the larynx collapses and obstructs during inspiration.
In conclusion, airway management of pediatric patients with concurrent VC and LM is challenging, with a high risk of total airway obstruction. We propose that awake fiberoptic intubation may be the preferred choice in experienced hands but reinforce the fact that even fiberoptic techniques may fail (14) with the potential for loss of airway patency (15,16). These cases require an individualized approach, a careful preoperative assessment, and a well thought out plan, which includes airway crisis management, back-up options, and a surgeon on standby. It is hoped that our experience will assist others in the management of such patients.
KS Cheng and JM Ng are Thoracic Anesthesia Fellows at the Brigham and Women’s Hospital. The authors would like to thank Simon C. Body, MD, for his invaluable advice and support in writing this manuscript.
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