Variability of the Pressure Measurements Exerted by the Tip of Laryngoscope During Laryngeal Sensory Testing: A Clinical Demonstration

Purpose Clinicians often test laryngeal sensation by touching the laryngeal mucosa with the tip of a flexible laryngoscope. However, the pressure applied to the larynx by using this touch method is unknown, and the expected responses elicited by this method are uncertain. The variability in pressure delivered by clinicians using the touch method was investigated, and the subject responses to the touches were also reported. Methods A fiberoptic pressure sensor passed through the working channel of a laryngoscope, with its tip positioned at the distal port of the channel. Two examiners each tested 8 healthy adults. Each examiner touched the mucosa covering the left arytenoid 3 times. The sensor recorded the pressure exerted by each touch. An investigator noted subject responses to the touches. From the recorded videos, the absence or presence of the laryngeal adductor reflex in response to touch was judged. Results Pressure values obtained for 46 of the 48 possible samples ranged from 17.9 mmHg to the measurement ceiling of 350.0 mmHg. The most frequently observed response was positive subject report followed by the laryngeal adductor reflex. Conclusion Pressure applied to the larynx by using the touch method was highly variable, indicating potential diagnostic inaccuracy in determining laryngeal sensory function.

Influence of motilin and cholecystokinin on sphincter of Oddi and duodenal mobility

The sphincter of Oddi and the duodenum exhibit cyclical activity in phase with the migrating myoelectric complex. Both motilin and cholecystokinin have been shown to modulate gastrointestinal and sphincter of Oddi motility. However, previous studies have not monitored the effects of these hormones on simultaneously recorded sphincter of Oddi and duodenum pressures. The present investigation was undertaken, therefore, to determine the influence of both motilin and cholecystokinin on simultaneously recorded sphincter of Oddi and duodenal motility. In seven anesthetized prairie dogs, a triple-lumen, side-hole, pressure-monitored perfusion catheter was positioned with the proximal port in the sphincter of Oddi and the distal port in the duodenal lumen. Sphincter of Oddi and duodenal motility was recorded before and during 20-min infusions of motilin and cholecystokinin octapeptide (CCK-8) at 1, 10, and 100 ng.kg-1.min-1. Both hormones produced dose-related increases in sphincter of Oddi and duodenal motility. No response was observed with either hormone at 1 ng.kg-1.min-1. At 10 ng.kg-1.min-1, the duodenum was slightly more sensitive to motilin than to CCK-8, while the sphincter of Oddi was equally affected by both hormones. At 100 ng.kg-1.min-1, both hormones stimulated the sphincter of Oddi and the duodenum equally. These data indicate that in the prairie dog, both motilin and cholecystokinin stimulate sphincter of Oddi and duodenal motility.