Dear Editor,
Flexometallic or armoured endotracheal tubes are very popular amongst anaesthesiologist for surgeries around head and neck. They offer several advantages like resistance to kinking and compression, exertion of minimal pressure on interarytenoid cartilages posteriorly and on trachea anteriorly. Commonly, oral route of insertion is preferred to the nasal route for these tubes. According to the traditionally held view, nasal passage of these tubes is considered extremely difficult or even impossible; hence anaesthesiologists the world over seldom use them via the nasal route.
However, as a routine we have been intubating the trachea with armoured tubes via the nasal route in various intraoral, mandibular and maxillofacial surgeries. In our experience, now in excess of 300 intubations, we experienced no difficulty in negotiating these tubes nasally. On the contrary, we found this technique simple, non-traumatic to the septum and the tubinates. In addition, these tubes invariably find their way into the oropharynx without getting stuck in the posterior pharyngeal wall, unlike the polyvinyl chloride (PVC) tubes, which not only cause disruption of pharyngeal mucosa and bleeding, but also make reintubation messy and difficult. The tip of the armoured tube is softer compared to its PVC counterpart and has a greater bevel angle. If the correct size of tube is used with gentle insertion pressure, the result is indeed very gratifying with no nasal trauma at all.
As is intuitively obvious, these tubes cannot be used for blind nasal intubation. In addition, when the Magill's forceps is used to guide the tube into the larynx, caution must be exercised to avoid damaging the cuff.
Flexometallic tubes can easily be angulated away from the surgical field, hence they also serve well as replacement for preformed tubes. Therefore, in our opinion flexometallic tubes should be used more frequently by the anaesthsiologist wherever nasal intubation is indicated.