Effects of nasal and laryngeal stimulation upon peripheral lung function.

Arterial hypoxemia and sudden death have been associated with the placement of posterior packs for control of severe epistaxis. There exists some controversy as to the mechanism underlying the clinically observed hypoxemia; some authors postulate a nasal pulmonary reflex as the basis for the hypoxemia. In an attempt to further investigate this theory, collateral ventilation was measured in the dog model during nasal and laryngeal stimulation. Collateral ventilation is thought to be one of the most sensitive techniques available to assess the resistive and elastic properties of the lung periphery. In the dog, with respiratory rate controlled (i.e., anesthetized and paralyzed), nasal stimulation with mechanical, thermal, and chemical stimuli failed to affect collateral ventilation. This finding suggests that the reflex may be acting either in larger lung segments or on the pulmonary vascular bed itself.