[abstract] ENDOSCOPIC STUDY OF GLOSSOPHARYNGEAL INSUFFLATION AND EXSUFFLATION.

Abstract

INTRODUCTION: Glossopharyngeal Insufflation (GI) is used by competitive breath-hold divers to inhale air above total lung capacity, while Glossopharyngeal Exsufflation (GE) is used to exhale air below residual volume. Here we report endoscopic description of these maneuvers. METHODS: Pharyngolaryngoscopy was performed in 4 competitive breath-hold divers (1 female and 3 males) during both GI and GE maneuvers. We used an Olympus fiberoptic laryngoscope attached to an Olympus video camera, with the film recorded on a VHS video tape. RESULTS: During GI, following the intake of air into the mouth and pharynx, the pharyngeal lumen was initially expanded, but then it contracted in a coordinated sequence involving elevation of the larynx, opening of the glottis, posterior displacement of the tongue and elevation of the palate, as air was injected into the trachea. In contrast to normal swallowing, during which, as the larynx is elevated, the vocal cords close to prevent aspiration, it was during the elevation phase of the GI maneuver that the larynx receive the injected bolus of air through abducted cords. As the next intake of air occurred, the vocal cords closed, trapping the air within the lungs, and the larynx dropped down. During GE, the pharynx was collapsed and the cheeks sucked in, as a negative pressure was created in the oral cavity and pharynx. Pinching the nostrils helped to maintain this negative pressure. The mouth was opened briefly to expel the air, just before another negative pressure cycle was initiated. Sequential, coordinated laryngeal elevation/descent was again noted, demonstrating vocal cord abduction during descent, and vocal cord closure during elevation. Again, in contrast to a normal swallow, the epiglottis stayed raised during the elevation of the larynx. SUMMARY: Both GI and GE are accomplished by a series of movements of the glossopharyngeal muscles and the larynx which moves extensively and repeatedly up and down, similar to a piston pump, to inject air into or extract it from the lungs.