Frenzel maneuver

The Frenzel maneuver is a voluntary technique for middle-ear equalization in which pressure is generated in the nasopharynx while the lower airway is isolated by closure of the glottis. The resulting nasopharyngeal pressure can open the Eustachian tubes, allowing gas to pass between the nasopharynx and the middle ear and reducing the pressure difference across the tympanic membrane.

The maneuver differs physiologically from the Valsalva maneuver. Valsalva equalization uses an expiratory effort against a closed airway and therefore raises intrathoracic pressure as well as upper-airway pressure, whereas the Frenzel maneuver generates the pressure required for equalization primarily within the upper airway while the glottis is closed. Frenzel equalization is used during changes in ambient pressure, particularly in aviation medicine and diving medicine. It is especially important in freediving, where progressive compression of pulmonary gas during descent can limit equalization techniques that depend upon generating pressure from the lungs.

The maneuver is named after German otolaryngologist Hermann Frenzel who first described the technique in his 1938 paper Nasen-Rachendruckversuch zur Sprengung des Tubenverschlusses.