Valsalva maneouvre

A Valsalva maneuver is a forced expiration against the nose and mouth held closed. Also known as Valsalva's test and Valsalva's method, it is named after Antonio Maria Valsalva, a famous Italian anatomist. Valsalva's initial intention for the maneuver was as a method of expressing pus form the middle ear.

Most people do Valsalva maneuvers inadvertently when blowing up balloons.

The Valsalva maneuver is used as a pressure equalisation technique by scuba divers and aeroplane passengers to avoid barotrauma and discomfort inside their ears when they move to or from a higher pressure breathing environment.

A person using this pressure equalisation technique pinches their nose, closes their mouth and tries to exhale. The technique works by raising the pressure in the throat so that a small volume of air moves from the throat to the ears through the Eustachian tube, which connects the two.

Medical uses of the Valsalva maneuver

A Valsalva maneuver also increases vagal tone (parasympathetic) transiently. It is worthwhile trying out a Valsalva to see if it will correct the heart rhythm of someone in supraventricular tachycardia.

Doing a Valsalva maneuver causes a transient lowering in ventricular filling and thus reduces the intensity of most cardiac murmurs. There are two exceptions to this rule, these being the murmur of hypertrophic cardiomyopathy and the murmur of mitral valve prolapse, which paradoxically become louder during a Valsalva maneuver.

Harrison's principles of Internal Medicine classifies four stages of a Valsalva maneuver, these being I - onset of expiration, II - continued expiration against a closed glottis, III - end of expiration and IV - recovery, and describes how the blood pressure and heart rate change during these phases. In a normal person, the heart rate decreases in phase I, increases in phase II and III and decreases in phase IV.

Some cardiologists measure the Valsalva ratio which is the maximum heart rate in phase II over the minimum heart rate in phase IV of the Valsalva Maneuver.