Use of the laryngeal mask airway (LMA; Laryngeal Mask Company, Henley-on-Thames, UK) in adults and children is widespread in the field of anesthesia. LMA provides an excellent airway in individuals not requiring the placement of a tracheal tube. Complications arising from the use of the LMA are typically mild and correctable, although more serious complications have been described. In this case report, we present a previously undescribed complication with the use of a LMA during placement of a Hickman catheter in a pediatric patient.
A previously healthy 9-mo-old girl who weighed 9.5 kg presented to the operating room (OR) for placement of a Hickman catheter to provide venous access for chemotherapy. The patient had recently been diagnosed with acute lymphocytic leukemia. The patient had no other medical problems and no craniofacial abnormalities. Her only medication was allopurinol, which had been started the previous day in anticipation of chemotherapy.
The patient was brought to the OR, and anesthesia was induced through a previously placed IV line by administering thiopental 5 mg/kg and fentanyl 0.5 μg/kg. After the induction, a No. 2 LMA was inserted without incident and inflated with 8 mL of air. The anesthetic was continued using sevoflurane in an air/oxygen mixture. The patient was then positioned with a shoulder roll placed beneath her shoulders, and the LMA was displaced, and the LMA was then reinserted and inflated again with 8 mL of air. After the reinsertion, the quality of ventilation was restored. No blood was noted on the LMA during the reinsertion. Surgery was then started.
During the blunt dissection in the carotid triangle around the right internal jugular vein (IJ) using mosquito clamps in a spreading fashion, the surgeon noted bubbles arising from the posterior aspect of the surgical site. These bubbles were coincident with ventilation. The patient remained hemodynamically stable and had an oxygen saturation of 100%. The surgeon could not identify any tract or path as the source of the air. The surgery was stopped, and the child was tracheally intubated without incident after the administration of 0.2 mg/kg of mivacurium. No traumatic lesion within the pharynx was noted during laryngoscopy, and the LMA was examined and found to be intact. Ventilation through the tracheal tube did not produce any air leakage from the wound. Positive-pressure ventilation was started with peak pressures remaining <30 mm Hg throughout the operative procedure. An otolaryngologist was consulted, and a laryngoscopy was performed, revealing a small right-sided pharyngeal hematoma.
The patient remained stable, and the neck wound was closed with a drain left in place. Surgery was continued on the left IJ, and a Hickman catheter was placed without incident. A chest radiograph taken in the OR was normal. The patient was allowed to emerge from anesthesia and was tracheally extubated without incident. The patient was transferred to the postanesthesia care unit (PACU) in a stable condition with an oxygen saturation of 98%–100% on room air. A repeat radiograph performed in the PACU revealed bilateral pneumothoraces. IV sedation was administered in the PACU (midazolam 1 mg and a total of 80 mg of propofol), and bilateral chest tubes were inserted. The patient was transferred to the intensive care unit for observation. The patient had an uneventful postoperative course during which the neck drain and the chest tubes were removed on the second postoperative day.
The use of the LMA in children is a safe and effective alternative to intubation or mask airway. There have been several large series investigating LMA use in children (1–4). These series found the LMA to be easy to use with a 96%–98% success rate with up to 2 attempts at insertion. Complications described in these studies include airway obstruction, upper airway reflex stimulation, persistent leaks with positive-pressure ventilation, and displacement of the LMA. Of these 1969 cases, there were only 6 patients who vomited during its use; none of these patients exhibited any symptoms resulting from aspiration (1–4). Overall, none of these studies reported any serious morbidity attributed to the LMA. The complication rate with a No. 1 LMA is more frequent than with the larger pediatric sizes (1,5,6).
Numerous complications with the LMA have also been documented in case reports. These include aspiration pneumonitis (7–10), negative-pressure pulmonary edema (11,12), arytenoid cartilage dislocation (13), macroglossia (14), tongue cyanosis (15), swelling of the parotid glands (16), posterior pharyngeal wall trauma (17), esophageal perforation (18), and nerve injury including the lingual (19), the hypoglossal (20), the twelfth cranial (21), and the recurrent laryngeal nerves (22). In our case, the air emanating from the wound had two possible sources: the pharynx and the lungs. In this case, the air was noted to be coming from the posterior region of the surgical site. The air leak was associated with ventilation and stopped once the patient was intubated. These findings suggest that the most likely source of the air was the pharynx. Presumably, the air was then able to track down the carotid sheath into the mediastinum and finally enter the pleural space. The communication between the pharynx and incision site probably occurred during the surgical dissection. We suspect that the size of the LMA (despite being appropriately sized for the child) was large enough to distort the anatomy at the incision site, such that the surgeon damaged the pharynx when creating a passage.
There are a number of case reports that support our premise that the LMA can distort neck anatomy. Riley et al. (23) described two cases in which they had trouble cannulating the IJ with the LMA inflated. With the LMA deflated, the carotid pulse became palpable, and the IJ was successfully cannulated. Patel and Pearce (24) described a case in which a LMA cuff was pierced by an 18-gauge Angiocath during an attempted right IJ cannulation. There have also been reports in which the LMA was mistaken by the surgeon during the operation as a neck mass (25–27). In two of these cases, a diagnostic needle biopsy was performed only to reveal the true nature of the mass. Other evidence that the pharynx had been entered was that the drain left in the neck was thought to have drained a small quantity of saliva on postoperative Day 1.
In general, LMAs in children are a safe and effective means of providing an airway. The volume of the LMA cuff when inflated is able to distort neck anatomy. We report the occurrence of airway trauma resulting from altered neck anatomy arising from the mass effect of the LMA cuff. We recommend that the LMA be used with increased caution in small children undergoing deep-neck dissection and that the surgeon be alerted to the possibility of altered anatomy resulting from the LMAs mass effect with its insufflation.
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