Nasal vasomotor responses in man to breath holding and hyperventilation recorded by means of intranasal balloons.

Nasal vasomotor responses were recorded in conscious human subjects by means of water filled balloons. Hyperventilation caused an increase in intranasal balloon pressure associated with vasodilatation whereas breath holding caused a decrease associated with vasoconstriction. The amplitude of the nasal vasomotor response was influenced by the nasal cycle with the greatest response always observed on the congested or low airflow side of the nose. The results suggest that an elevated arterial level of carbon dioxide causes a pronounced vasoconstruction of the nasal blood vessels and that this response may be clinically relevant in controlling nasal bleeding.