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Transcript
Valsalva maneuver
The Valsalva maneuver is performed by forcibly exhaling against a closed airway. Variations of
the maneuver can be used either in medicine, as a test of cardiac function and autonomic
nervous control of the heart or to ‘clear’ the ears and sinuses (equalize pressure) when
ambient pressure changes, as in diving or aviation.
The technique is named after Antonio Maria Valsalva, the 17th 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.
Physiological response
Blood pressure (systolic and diastolic) and pulse rate during a normal response to Valsalva’s
maneuver. Forty millimeter mercury pressure is applied at 5 seconds and relieved at 20
seconds.
The normal physiological response consists of 4 phases, which are marked on the figure at
right:
1. Initial pressure rise: On application of expiratory force, pressure rises inside the chest
forcing blood out of the pulmonary circulation into the left atrium. This causes a mild
rise in blood pressure.
2. Reduced venous return and compensation: Return of systemic blood to the heart is
impeded by the pressure inside the chest. The output of the heart is reduced and blood
pressure falls. This occurs from 5 to about 14 seconds in the illustration. The fall in
blood pressure reflexively causes blood vessels to constrict with some rise in pressure
(15 to 20 seconds). This compensation can be quite marked with pressure returning to
near or even above normal, but the cardiac output and blood flow to the body remains
low. During this time the pulse rate increases.
3. Pressure release: The pressure on the chest is released, allowing the pulmonary
vessels and the aorta to re-expand causing a further initial slight fall in pressure (20 to
23 seconds) due to decreased left ventricular return and increased aortic volume,
respectively. Venous blood can once more enter the chest and the heart, cardiac
output begins to increase.
4. Return of cardiac output: Blood return to the heart is enhanced by the effect of entry
of blood which had been dammed back, causing a rapid increase in cardiac output and
of blood pressure (24 seconds on). The pressure usually rises above normal before
returning to a normal level. With return of blood pressure, the pulse rate returns
towards normal.
Deviation from this response pattern signifies either abnormal heart function or abnormal
autonomic nervous control of the heart. Valsalva is also used by dentist following extraction of
a maxillary molar tooth. The maneuver is performed to determine if a perforation or antral
communication exist.
Normalizing middle ear pressures
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. It should be noted 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. 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. Opening can often be clearly heard by the practitioner, thus providing feedback that the
maneuver was successful.
The reason opening the mouth is successful while trying to open the Eustachian tubes is
because when the jaw is closed, it pinches these tubes, restricting flow. Opening the mouth
relieves the pinching. Thus, while using the Valsalva maneuver, having the jaw open (with lips
shut) will make it much more successful. This is also the reason some people recommend to
chew gum during an airplane descent, because the chewing motion of the jaw opens the
Eustachian tubes.
Note that in a clinical setting the Valsalva maneuver will be done either against a closed
glottis, or against an external pressure measuring device, in each case either eliminating or
minimizing the pressure on the Eustachian tubes. Straining, blowing against resistance as in
blowing up balloons has a Valsalva effect and the fall in blood pressure can result in dizziness
and even fainting.
Cardiology
The Valsalva maneuver may be used to arrest episodes of supraventricular tachycardia. The
maneuver can sometimes be used to diagnose heart abnormalities, especially when used in
conjunction with echocardiogram For example, the Valsalva maneuver classically increases the
intensity of hypertrophic cardiomyopathy murmurs, viz. those of dynamic subvalvular left
ventricular outflow obstruction; whereas it decreases the intensity of all other murmurs,
including aortic stenosis and atrial septal defect.
Effect of Valsalva Cardiac Finding
Aortic Stenosis
Decreased
Pulmonic Stenosis
Tricuspid Regurgitation
Increased
Hypertrophic cardiomyopathy, mitral valve prolapse
Neurology
The Valsalva maneuver is used to aid in the clinical diagnosis of problems or injury in the
nerves of the cervical spine. Upon the exertion of pressure, neuropathies or radicular pain may
be felt, and may indicate impingement on a nerve by an intervertebral disc or other part of the
anatomy.
Valsalva retinopathy
A pathologic syndrome associated with the Valsalva maneuver is Valsalva retinopathy. It
presents as preretinal hemorrhage (bleeding in front of the retina) in people with a history of
transient increase in the intrathoracic pressure. The bleeding may be associated with a history
of heavy lifting, a forceful coughing, straining on the toilet, or vomiting. The bleeding may
cause a reduction of vision if it obstructs the visual axis. Patients may also note floaters in
their vision. Usually a full recovery of vision is made.