The use of a supraglottic airway1,2 is well established in clinical anesthesia and difficult airway management.1,2 However, it is associated with an assortment of complications ranging from failure, dislodgement, pulmonary aspiration, laryngospasm, and oropharyngeal trauma.3–6 This report presents an unusual complication with the use of a King Laryngeal Tube (King LT, King Systems, Noblesville, IN) and a plausible explanation. Written consent was obtained from the patient to publish this report.
A healthy, 18-year-old man was scheduled for removal of hardware from his right knee. He was 171 cm tall and weighed 57 kg with no comorbidities or any known allergies. In the operating room, after establishing standard monitors, anesthesia was induced with IV 1 mg midazolam, 40 mg lidocaine, 120 mg propofol, and 50 μg fentanyl; it was easy to ventilate him with a facemask. A size 4 King LT was lubricated and inserted with ease until the base of the connector aligned with the teeth. The cuff was inflated with 70 mL of air using the syringe provided. Initially, it was difficult to ventilate. While gently squeezing the bag, the tube was withdrawn slightly until ventilation was easy with minimal airway pressure. The pressure in the cuff was checked with a cuff pressure gauge (King Systems, Noblesville, IN) and found to be 70 cm H2O, which was promptly reduced to 60 cm H2O in accordance with the manufacturer’s safety recommendations. At the end of an uneventful surgery, the King LT airway was removed. A slight reddish tinge was noticed in the secretions around the cuff of the airway.
The patient was conscious, breathing spontaneously, and was transferred to the postanesthesia care unit. An hour and a half later, when he was encouraged to drink clear fluids, he reported “something stuck in my throat” and he found it painful to swallow water. He did not have any difficulty breathing nor did he have a stridor. It was also noticed that he developed a blotchy, non-itchy rash over his chest, which was transient and developed at different areas and disappeared spontaneously within a few minutes. According to his mother, he developed this transient rash in the past when he exercised or was anxious. She reported that it goes away spontaneously without needing treatment.
Examination of the oropharynx revealed a bluish red fleshy mass approximately half a centimeter in diameter and more than a centimeter long, which the patient was able to “bring up” using the back of his tongue. The otolaryngologist identified it as the edematous and ecchymotic uvula with its tip reaching nearly up to the epiglottis. The uvula was engorged and had a blanched line across the base, suggesting that it may have been folded on itself (Fig. 1). The rest of the oral and pharyngeal mucosa appeared normal. There was no congestion or edema of the epiglottis, the aryepiglottic folds, the arytenoids, or the postcricoid region. The glottis was patent during inspiration, and the vocal cords were normal with good apposition on phonation. No further treatment was recommended. The patient was discharged home and advised to return immediately if the symptoms increased or if he had difficulty breathing.
The next morning, his mother reported that he slept well overnight, but still found it difficult to swallow fluids. On the third postoperative day, he was able to swallow fluids with minimal discomfort.
Since the introduction of the laryngeal mask airway (LMA®) Classic in 1988, supraglottic airway devices with variation in design and shape of the cuff have become available.1 Anatomically, the location of the cuff could be periglottic (e.g., LMA, AMBU®), pharyngeal (e.g., Cobra PLA [Engineered Medical Systems, Indianapolis, IN]), or dual, a distal one to block the esophagus and the proximal one in the oropharynx (e.g., King LT, Combitube [Covidien Ltd., Dublin, Ireland]).1 The essential purpose of the cuff is to create a soft seal around the laryngeal opening to direct the passage of gas down the airway into the trachea.
The structural difference in the location of the cuff determines the anatomical area of the oropharynx on which the cuff exerts its pressure. The cuff of the LMA is distal and presses around the glottis opening and the pyriform fossa extending into the esophageal opening, whereas the proximal cuff of the King LT is located midshaft and presses more cephalad into the soft palate, posterior pharyngeal wall, and the base of the tongue, and the distal one seals the esophagus (Fig. 2). The product insert provided with the King LT recommends a fixed volume of air to be injected into the cuff to create a seal.a It is obvious that the pressure in the cuff would be determined by the space available in the oropharynx.
Another difference between the LMA and the King LT is that after insertion when the cuff is inflated, the LMA seems to “rise” up as the inflated cuff tries to find its place around the glottis opening, whereas the King LT seems to stay, or at times move down, to find the right place to lodge the spherical cuff. The recommended technique of using the King LT is to insert it deep enough to align the base of the connector to the teeth or gums and inflate the cuffs with a fixed volume of air using the syringe that is provided. Then, while gently squeezing the reservoir bag, the tube is withdrawn slightly until ventilation becomes easy and adequate tidal volume can be delivered with minimal airway pressure.a
While withdrawing the tube, the inflated cuff, if located below the uvula, could drag the uvula up and fold it on itself, especially if the cuff pressure is high. The splinting of the uvula in that position for the duration of the surgery could explain the situation described here. The fact that the cuff pressure was regulated to 60 cm H2O and that the duration of the surgery was short may have been the reason that the uvula did not undergo permanent damage. Although the presence of “blood-tinged” secretions over the airway could suggest direct trauma during insertion, it could have been secondary to the edema and the congestion of the uvula.
Edema of the uvula is rare and may be associated with angioedema, urticaria, or anaphylaxis.7 It has been described after oral surgery, infection, snoring, and obstructive sleep apnea. In their study to identify the etiology of edema of the uvula, Alcoceba et al.7 found 55% (n = 58) to be idiopathic and in the remaining incidents, the leading cause was allergy. A few occurrences were related to medications, and one was because of cannabis smoking. In the patient described here, an atopic manifestation could have been a differential diagnosis, considering the fact that he developed a transient blotchy rash, which was perhaps stress-induced. However, the congested uvula with a demarcating hypoemic line at its base and absence of any hyperemia over the pharyngeal or laryngeal mucosa points more toward a mechanical etiology.
The use of supraglottic airway devices is well established in airway management for anesthesia, especially in difficult airway situations.2 Moreover, its use by paramedics, as a primary airway device in out-of-hospital cardiac arrests, is likely to increase.8 Therefore, it is important to be aware of the complications associated with its use.
a Available at: http://www.narescue.com/media/NAR/guides/ISG-KingLTD.pdf. Accessed April 16, 2015.
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