Partial airway obstruction following manufacturing defect in laryngeal mask airway (Laryngeal Mask Silken™).

Laryngeal mask (LM) airway is commonly used for securing airway in day-care surgeries. Various problems have been described while using LM airway. Out of those, mechanical obstruction causing airway compromise is most common. Here, we describe a case report of 4-year-old child who had partial upper airway obstruction due to LM manufacturer's defect. There was a silicon band in upper one-third of shaft of LM airway. This band was made up of the same material as that of LM airway so it was not identifiable on external inspection of transparent shaft. We suggest that such as non-transparent laryngeal mask, a transparent LM airway should also be inspected looking inside the lumen with naked eyes or by using a probe to rule out any manufacturing defect before its insertion.

INTRODUCTION

Laryngeal mask (LM) airway has been used successfully in day care set-up and short surgical procedures. Upper airway obstruction can occur secondary to laryngospasm, malpositioning of LM airway, a foreign body obstructing the lumen or folding of epiglottis over laryngeal inlet. There are few case reports describing upper airway obstruction as a result of mechanical obstruction.[1]

CASE REPORT

A 4-year-old child was scheduled for congenital cataract surgery under general anesthesia. After attaching standard monitors, inhalation induction was undertaken using the sevoflurane. After securing IV line, injection fentanyl was administered and size-2 reusable Laryngeal Mask Silken (LM-Silken, Romsons, Agra, India) was inserted in sniffing position. Although the patient was breathing spontaneously, suprasternal retraction was observed, suggesting partial upper airway obstruction. Since there was no change in EtCO2 it was decided to proceed with surgery. Completion of surgery was uneventful and LM-Silken was removed in deep plane of anesthesia. Suprasternal retraction disappeared immediately, confirming the intraoperative airway obstruction due to LM-Silken. On inspection, a silicon band was detected in the upper-third lumen of LM-Silken shaft, apparently causing partial airway obstruction [Figure 1].

Figure 1

Laryngeal mask airway showing silicon band

DISCUSSION

This band being of the same color and consistency as that of LM-Silken material was missed on external visual inspection before use. Manufacturer's defects such as, meniscus or plastic films causing intraluminal obstruction have been earlier described in tracheal tubes.[12] Solaidhanasekaran and Bharamgoudar reported a case in which LM airway caused upper airway obstruction secondary to cuff herniation.[3] In another case report, Ungern-Sternberg and Erb described an upper airway obstruction following the detachment of the cuff weld near the tip of the pediatric LM airway.[4]

An external visual inspection of LM airway is routinely recommended to rule out any foreign material in the lumen likely to cause airway obstruction. In our case, since the intraluminal defect was of the same material as that of LM-Silken, it could not be visualized by external inspection before its use. We suggest that such as non-transparent laryngeal mask, a transparent LM airway should also be inspected looking inside the lumen with naked eyes or by using a probe to rule out any manufacturing defect before its insertion.