Valsalva Maneuver
The Valsalva maneuver is a coordinated muscular movement that increases pressure in the Eustachian tubes and middle ears. The maneuver produces a bilateral increase in pressure on both the left and right middle ears. The maneuver was first described by Italian anatomist Antonio Maria Valsalva (1666-1723). The Valsalva maneuver may occur as a result of natural muscle movements during defecation, coughing, or gagging, or as an induced maneuver.
The natural Valsalva maneuver occurs when exhaled air is blocked by a closed glottis. In addition to causing pressure changes in the Eustachian tubes, the Valsalva maneuver has a number of physiological side effects. The maneuver causes a decrease in the return of venous blood to the heart and decrease in blood pressure. When the airway is reopened, blood pressure increases and the heart race increases until slowed by a reflex slowing (brachycardia).
The artificial maneuver requires that the nostril passages be blocked or obstructed. In addition to mechanical devices that can pinch off the airway, a slight pressure pinch of the thumb and forefinger is usually sufficient to close the airway. Increasing pinching pressure, and a concurrent tightening of the mouth, lips and cheek muscles keep the airway closed as increasing pressure build in the lungs and chest. As a result of the closures and pressurization, the Eustachian tubes become pressurized./
Divers frequently use the Valsalva maneuver to counteract the effects of water pressure on the Eustachian tubes and to eliminate pressure problems associated with the middle ear. When subjected to pressure the tubes may collapse or fail to open unless pressurized. Eustachian tubes connect the corresponding left and right middle ears to the back of the nose and throat and function to allow the equalization of pressure in the middle ear air cavity with the outside (ambient) air pressure. The degree of Eustachian tube pressurization can be roughly regulated by the intensity of abdominal, thoracic, neck and mouth muscular contractions used to increase pressure in the closed airway. Divers commonly achieve pressurizations in the Eustachian tubes that are able to counteract the collapsing pressure found at a depth of about ten feet.
Although the Valsalva maneuver is one of the simplest procedures to perform to pressurize or equalize pressure in the Eustachian tubes and middle ear, there are a number of others techniques including the Frenzel maneuver, Toynbee maneuver and French Navy's Beance Tubaire Volontaire (BTV). The techniques all require some closure of the airway and the manipulation of the tongue, plate or muscles associated with respiration or swallowing to achieve pressurization of the Eustachian tubes that can open the tubes and subsequently allow for an equalization of pressures with the middle ear.
Although a common maneuver preformed by underwater divers to pressurize or clear Eustachian tubes, the Valsalva maneuver can have adverse consequences if performed too vigorously, or if performed by individuals with certain diseases or abnormalities affecting the middle ear. The maneuver should not be attempted without proper instruction and supervision.
In individuals with some forms of heart disorders, the reflex bracycardia following the Valsalva maneuver may lead to cardiac arrest.
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