All 31 subjects underwent LPSDT with the use of an air-pulse stimulator via a nasendoscope. The threshold of laryngopharyngeal sensation was evaluated by measuring the amount of air pressure required to elicit the laryngeal adductor reflex (LAR).
The nasendoscope (FNL- 10 AP; KayPENTAX; Montvale, N.J.) was attached to an air-pulse sensory stimulator (AP4000; KayPENTAX), and it was then passed transnasally through to the laryngopharynx until it became situated approximately 3 mm above the arytenoid eminence.
At 3 out of 7 institutions, a 00 rigid nasendoscope
was never/sporadically available; one frequently had no headlights available, and registrars had to provide their own.
Further examination can be assisted with the help of a flexible nasendoscope
passed through the lumen of the tube to assess the lower airway.
The airway requires thorough investigation with a flexible nasendoscope
and plain film x-rays can provide an initial evaluation; lateral neck views may demonstrate prevertebral soft tissue swelling and a chest x-ray can provide an estimate to degree of extension (7).
Due to availability of equipment, a nasendoscope
(Olympus ENF P3, Olympus Optical, Tokyo, Japan) inserted nasally was used at one institution and a gastroscope (Evis Exera 160 series gastroscope, Olympus Optical, Tokyo, Japan) inserted orally was used at the other.