Valsalva maneuver

1961, William L. Watson, The Valsalva Maneuver: Its Relationship to Chronic Recurrent Aerotitis Media, Review 5-61, USAF Aerospace Medical Center, Brooks Air Force Base, page 2, One generally accepted way of equalizing the pressure is by performing the Valsalva maneuver.

2008, Curtis B. Kamida, et al., 15: Lower extremity ascending and descending phlebography, Peter Gloviczki, Handbook of Venous Disorders, Taylor & Francis (CRC Press), page 165, A Valsalva maneuver initially causes cessation of prograde flow, and then actual flow reversal.