Valsalva maneuver

The Valsalva maneuver is performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while pressing out as if blowing up a balloon. Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to clear the ears and sinuses (that is, to equalize pressure between them) when ambient pressure changes, as in diving, hyperbaric oxygen therapy, or air travel. The Valsalva maneuver is performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while pressing out as if blowing up a balloon. Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to clear the ears and sinuses (that is, to equalize pressure between them) when ambient pressure changes, as in diving, hyperbaric oxygen therapy, or air travel. The technique is named after Antonio Maria Valsalva, a seventeenth-century physician and anatomist from Bologna whose principal scientific interest was the human ear. He described the Eustachian tube and the maneuver to test its patency (openness). He also described the use of this maneuver to expel pus from the middle ear. A modified version is done by expiring against a closed glottis. This will elicit the cardiovascular responses described below but will not force air into the Eustachian tubes. The normal physiological response consists of four phases. Deviation from this response pattern signifies either abnormal heart function or abnormal autonomic nervous control of the heart. Valsalva is also used by dentists following extraction of a maxillary molar tooth. The maneuver is performed to determine if a perforation or antral communication exists. When rapid ambient pressure increase occurs as in diving or aircraft descent, this pressure tends to hold the Eustachian tubes closed, preventing pressure equalization across the ear drum, with painful results. To avoid this painful situation, divers, caisson workers and aircrew attempt to open the Eustachian tubes by swallowing, which tends to open the tubes, allowing the ear to equalize itself. If this fails, then the Valsalva maneuver may be used. This maneuver, when used as a tool to equalize middle ear pressure, carries with it the risk of auditory damage from over pressurization of the middle ear. It is safer, if time permits, to attempt to open the Eustachian tubes by swallowing a few times, or yawning, or by using the Valsalva technique of breathing a very small amount of air gently into nostrils held closed by the fingers as soon as mild pressure is felt, before it increases to the point that its release would be painful. The effectiveness of the 'yawning' method can be improved with practice; some people are able to achieve release or opening by moving their jaw forward or forward and down, rather than straight down as in a classical yawn, and some can do so without moving their jaw at all by activating the tensor tympani muscle, which is heard by the individual as a deep, rumbling sound. Opening can often be clearly heard by the practitioner, thus providing feedback that the maneuver was successful. During swallowing or yawning, several muscles in the pharynx (throat) act to elevate the soft palate and open the throat. One of these muscles, the tensor veli palatini, also acts to open the Eustachian tube. This is why swallowing or yawning is successful in equalizing middle ear pressure. Contrary to popular belief, the jaw does not pinch the tubes shut when it is closed. In fact, the Eustachian tubes are not located close enough to the mandible to be pinched off. People often recommend chewing gum during ascent/descent in aircraft, because chewing gum increases the rate of salivation, and swallowing the excess saliva opens the Eustachian tubes.