The intubating laryngeal mask (ILM) is a modification of the conventional laryngeal mask airway which is designed to act as a ventilatory device and an aid for blind tracheal intubation (TI) in patients with normal and abnormal airways . Tracheal intubation through the ILM is a 'blind-on-blind' technique , because both the ILM and the tracheal tube (TT) are inserted without direct vision of the larynx. Whenever resistance is felt during TT insertion a variety of strategies may be instituted depending on the likely cause . Different malpositions may be detected by noting the indication of the depth in relation to the transverse marker at which passage of the TT became blocked . According to this management strategy, when resistance is felt at a depth of more than 4 cm the use of a smaller size of ILM is suggested . However, there are some rare causes of resistance which may not be included in this suggested strategy. We would like to report our experience where the use of a light-guided technique for TI through the ILM facilitated the diagnosis in a case of unexpected resistance during TT insertion.
A 75-year-old woman (weight 45 kg, height 152 cm) was scheduled to undergo cholecystectomy under general anaesthesia. After induction with propofol 2.0 mg kg−1, fentanyl 1 μg kg−1 and cisatracurium 0.15 mg kg−1 an ILM size 4 was inserted to act as a ventilatory device and an aid for light-guided intubation by using a prototype illuminated flexible catheter (IFC) . The device of the IFC consists of a completely flexible thin plastic catheter (length 30 cm, external diameter 5 mm), without any metallic component, which at its distal end comprises a bulb of adequate brightness fixed with atoxic glue and silicone. The IFC was placed into a straight flexible TT (Rusch) 7.0 mm ID, in such a way that the bulb protruded from the distal end of the TT . Successful placement of ILM was judged by chest wall movement and capnography, in addition to the ability to deliver a tidal volume of 8 mL kg−1 without a leak at an airway pressure of 20 cmH2O. During insertion of the TT via the ILM we observed a bright glow in the midline at the level of the laryngeal prominence that continued the downward movement, indicating correct placement of the TT in the trachea . However, at the level of the suprasternal notch resistance was felt unexpectedly and although the TT was inside the trachea, the intubation was not completed. We exchanged the TT for a smaller one (6.5 mm ID) and on the second attempt, the TT was inserted without any resistance. Post-operatively, an X-ray of the soft tissues of the neck revealed a tracheal stenosis at the clavicular level.
The use of a light-guided methodology gave us the ability for exact localization of the TT tip. Thereafter the possible cause of resistance in TT passage was diagnosed and a possible TI failure via the ILM was avoided.
G. S. VOYAGIS
Department of Anaesthesiology, Gennimatas and Sotiria Hospitals, Athens, Greece
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