Nasal intubation: some postnasal obstructions and how they may be overcome.

During the passage of a tube from nostril to trachea certain difficulties may be encountered. The anterior nasal opening may be unusually narrow, there may be a septal deflection or spur, or an inferior turbinate;; may be tiresomely over-sized. On such occasions, of course, the effect of rotation of the tube is tested, the other nostril is tried, or a narrower^ tube used. However, a little beyond the deflected septum or the oversized turbinate there is quite frequently firm resistance to progress of the tube. This has. rather vaguely been considered to be due' to adenoids or their remnants, to deformities or to scar tissue; and indeed at times such may be the case. But digital examination shows that die com-monest causes of obstruction on the posterior wall of the nasopharynx are a prominent anterior arch of the atlas (fig. 1) or the hollow above it (fig. 2). It is at these points that the tip of the endotra-cheal tube may be resisted in its passage through the nasopharynx. Such prominence of the atlas may be accentuated by Passavant's bar or ridge, which is made up of the fibres of the horizontal part of the palato-pharyngeus muscle where they meet their fellows of the opposite side, forming with the soft palate a sphincter between oro-and nasopharynx (Townshend, 1940). This sum muscular ridge lies on the anterior arch of the atlas but is probably of little significance when relax-ants are used and the sphincter is fully relaxed. Rarely, a tube may be held up on the lateral wall of the pharynx in one or other of the pharyngeal recesses (or fossae of Rosenmuller), hollows of variable depth, one on each side, above and behind the tubal elevations (or Eustachian cushions); but almost all tubes passed nasally take a course medial to these structures. It is also possible for the tip of the tube to be caught up in the adenoids and perhaps in the 115 FIG. 1 A nasal tube (filled with radio-opaque substance) shown impacted on a prominent anterior arch of the a young man anaesthetized through an orotracheal tube. atlas 116 BRITISH JOURNAL OF ANAESTHESIA FIG. 2 A nasal tube (with a malleable stillette inside it) shown impacted in the hollow above a prominent anterior arch of the atlas in an elderly edentulous patient. pharyngeal bursa. This enigmatic bursa, to the anaesthetist, is entirely a textbook entity, and to …