Valsava maneuver - BE AWARE
In medicine, the Valsalva maneuver is performed by forcibly exhaling against a closed glottis (a closed airway). This maneuver with slight modifications can be used 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 Valsalva maneuver is performed by attempting to forcibly exhale while keeping the mouth and nose closed. It is used as a diagnostic tool to evaluate the condition of the heart and is sometimes done as a treatment to correct abnormal heart rhythms or relieve chest pain.
The technique is named for 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).
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.
1. Expiratory effort when the mouth is closed and the nostrils are pinched shut, which forces air into the eustachian tubes and increases pressure on the inside of the eardrum.
2. Expiratory effort against a closed glottis, which increases pressure within the thoracic cavity and thereby impedes venous return of blood to the heart.
What happens during this maneuver is that, when one tries to expell out air forcefully with a closed glottis, there is generation of high +ve intrapleural pressure , which impedes right sided venous return and initially compresses the lungs which squeezes out the blood which was previously accumulated during inspiration, this initially results in inc. in venous return to left heart and subsequent CO and heart rate goes down, but after some time due to resistance across pulmonary vasculature, venous return to left heart decreases as well along with left sided cardiac output, and heart rate shoots.
Valsalva Maneuver is particularly helpful in evaluation of valvuar disorders, eg: it differentiates between ejection murmur of aortic stenosis and HOCM.
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. Valsava is also used by dentist following extraction of a maxillary molar tooth. The manuever is performed to determine if a perforation or antral communication exist.
The Valsalva maneuver is used with patients who have suspected heart abnormalities, often in conjunction with echocardiography. The maneuver is based on the fact that when a patient forcibly exhales against a closed nose and mouth while bearing down, as if having a bowel movement, specific changes occur in blood pressure and the rate and volume of blood returning to the heart.
Comparing the changes in a diseased heart to those expected in a normal heart gives clues to the type and location of heart damage. In addition, when a doctor listens to the chest with a stethoscope during the Valsalva maneuver, characteristic heart sounds are heard. Variations in these sounds can indicate the type of abnormality present in the heart. A 2004 study found that blood pressure response to the Valsalva maneuver could predict mortality in elderly patients with congestive heart failure. This could prove to be a new noninvasive way to help determine how long elderly patients with congestive heart failure are expected to live.
The Valsalva maneuver also corrects some rapid heartbeats originating in the atria. When the maneuver is done correctly, blood pressure rises. This forces the heart to respond by correcting its rhythm and beating more slowly. On rare occasions, the Valsalva maneuver can be used to diminish chest pain in patients with mild coronary disease.
Unrelated to any evaluation of the heart, the Valsalva maneuver also is taught to patients with multiple sclerosis who are unable to fully empty the bladder (flaccid bladder). It sometimes is used in sexual therapy to help men avoid premature ejaculation.
The Valsalva maneuver should not be performed by patients who have severe coronary artery disease, have experienced recent heart attack, or have a moderate to severe reduction in blood volume.
When performed formally, the patient is asked to blow against an aneroid pressure measuring device (manometer) and maintain a pressure of 40 millimeters of mercury (mm Hg) for 30 seconds. Or, less formally, the patient may be asked to bear down, as if having a bowel movement. During this 30 second period, a recording is made of the changes in blood pressure and murmurs of the heart.
The patient may be connected to a heart monitor and echocardiograph or the physician may simply use a stethoscope to monitor the heart. Sometimes an indwelling needle is inserted for accurate pressure measurements, depending on whether the procedure is being done for corrective or diagnostic purposes.
When this procedure is done to regulate irregular heart rhythms, the patient usually remains on a heart monitor to evaluate heartbeat.
The patient may feel dizzy or faint during the procedure, but serious consequences are rare. There is a risk that the Valsalva maneuver can cause blood clots to detach, bleeding, and abnormal rhythms originating in the ventricle. It can also cause cardiac arrest. Consequently, the procedure is usually performed in a setting where emergency equipment is accessible.
There are four characteristic changes or phases in a normal heart's response to the Valsalva maneuver. An abnormality in any of these phases indicates a cardiovascular abnormality.
Valsalva maneuver may be contraindicated in a variety of cardiovascular conditions, including for example, hypertrophic obstructive cardiomyopathy, significant aortic valvular disease, recent myocardial infarction, aortic stenosis, glaucoma, retinopathy...
ALWAYS HAVE ON YOUR MIND CONTRAINDICATIONS