Intubating laryngeal mask airway allows tracheal intubation when the cervical spine is immobilized by a rigid collar

An intubating laryngeal mask airway (ILMA) facilitates tracheal intubation with the neck in neutral position, which is similar to the neck position maintained by a rigid cervical collar. However, a cervical collar virtually obliterates neck movement, even small movements that normally facilitate airway insertion. We therefore tested the hypothesis that the ILMA will allow tracheal intubation even in patients wearing a rigid cervical collar.

We performed blind tracheal intubation via an ILMA under general anaesthesia in 50 patients with a rigid Philadelphia collar in place undergoing cervical spine surgery and 50 general surgical patients. Time required for intubation, intubation success rate, and numbers and type of adjusting manoeuvres used were recorded.

Inter-incisor distance was significantly smaller (4.1 (0.8) vs 4.6 (0.7) cm, mean (sd), P<0.01) and Mallampati scores were significantly greater (P<0.001) in the patients with collars. ILMA insertion took longer (30 (25) vs 22 (6) s), more patients required two insertion attempts (15 vs 3; P<0.005), and ventilation adequacy with ILMA was worse (P<0.05) in collared patients. However, there were no significant differences between the collars and control patients in terms of total time required for intubation (60 (41) vs 50 (30) s), number of intubation attempts, overall intubation success rate (96 vs 98%), or the incidence of intubation complications.

Blind intubation through an ILMA is thus a reasonable strategy for controlling the airway in patients who are immobilized with a rigid cervical collar.