The intubating laryngeal mask airway (ILMA) in failed and difficult intubation

We were interested to read about the three cases of difficult intubation overcome by the use of the ILMA (Anaesthesia 1998; 53: 343–8). We have similarly noted success rates comparable to those of the original investigators [1, 2] in a series of 100 patients with normal airways. However, we wish to report one case in which tracheal intubation via the ILMA proved unsuccessful.

A 58-year-old Chinese man with myasthenia gravis was admitted to the intensive care unit because of ventilatory failure 2 days after an emergency appendicectomy. At the time of surgery, trachael intubation had proved impossible following rapid sequence induction and was eventually achieved using a fibreoptic bronchoscope, after the patient had safely been woken up. Postoperatively, he had been sent to the high dependency unit. On admission to ICU, he was responsive to commands and was able to maintain an oxygen saturation of 98%, but breathing was laboured with shallow tidal volumes, it was possible to manually assist ventilation using a facemask. Following propofol 20 mg, direct laryngoscopy revealed a grade 4 view [3]. Tracheal intubation was attempted, using a gum elastic bougie and stylet, by three specialist anaesthetists, with no success. Initial use of the fibreoptic bronchoscope also proved unsuccessful. A size 4 ILMA was then inserted and adequate ventilation achieved. However, it proved impossible to pass a size 7.0 mm silicon tracheal tube via the ILMA. A fibre-optic bronchoscope was passed down the metal stem of the ILMA, but the view was obscured because of bleeding. The ILMA was removed and after further tries the trachea was eventually intubated using a size 7.0 mm tracheal tube railroaded over a fibreoptic bronchoscope passed nasally.

It is important to report both success and failure especially since the ILMA is a new device which has been developed based on MRI studies in one particular population. In addition, all three cases described by Parr et al. had received neuromuscular blockers to aid intubation.