A case of breakage of LMA Supreme on its first use.

Sir,

We are reporting a case of incomplete circumferential break of a single use LMA Supreme™ on its first use which got unnoticed at the first instance.

A 40-year-old moderately built lady scheduled for open reduction and internal fixation of fracture of right head of humerus. She was a known case of rheumatoid arthritis and was on treatment.

After conventional induction of general anaesthesia using propofol and fentanyl, anaesthesia was maintained with isoflurane in nitrous oxide and oxygen. Mask ventilation was fairly easy and LMA Supreme™ size 3 was smoothly placed. Cuff was inflated with 20 ml of air. LMA Supreme™ cuff was checked prior to insertion. The patient was ventilated on volume controlled mode using Datex Engstrom anaesthesia machine. End tidal CO2 was maintained at 35 to 40 mm of Hg.

After an uneventful one hour or so, close to the end of surgery, a flat capnograph trace and collapsed bellows were noticed. A quick check on the patient circuit and the machine revealed a gas leak from the sides of LMA Supreme™ but the exact site of leak was undetected. The LMA Supreme™ was removed and mask ventilation using a Guedel airway size 4 was successfully instituted without any circuit leak. Closer examination of the LMA Supreme™ did not reveal any defect, so we planned to reinsert the LMA Supreme™. After insertion of LMA Supreme™ during connecting circuit to the LMA, we noticed a near complete circumferential break at the junction of bite block and airway and drain tube port which was the cause of the leak in the circuit [Figure 1]. LMA Supreme™ was removed immediately and oral airway replaced. Remaining course of anaesthesia and recovery were uneventful.

Figure 1

Breakage of LMA Supreme™

LMA Supreme™ [Figure 2] is a single use supraglottic airway device manufactured by Laryngeal Mask Company Ltd. Le Rocher, Victoria, Mahé,[1] Seychelles. It has a rigid moulded proximal component which forms separate airway and drain tube ports. This component is fixed to the bite block. The fracture site was at the junction of proximal component and bite block.

Figure 2

LMA Supreme™

This break was not noticed in the first instance as it was incomplete circumferential break acting like a hinge allowing the fresh gas to leak out in inspiratory phase and remain closed in the expiratory phase.

Insertion of LMA Supreme™ in this particular case was easy and possible in single attempt. We strictly complied with the company instruction on insertion technique and cuff inflation volume.[2]

There was no stretching of the anaesthesia circuit as it was well fixed on an L-shaped fixator close to the patient head which excludes the possibility of undue stress on the airway port causing it to break.

We were not able to trace similar incident reported in our literature search.