Performed by locking an inflated blood pressure cuff at 15 mm HG above the resting supine systolic blood pressure so Korotkoff sounds can not be heard, at which time the patients performs a sustained Valsalva exhalation against a closed glottis for about 10 seconds.
The procedure 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 utilized in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to clear the ears and sinuses by equalizing pressure between them when ambient pressure changes, as in diving, hyperbaric oxygen therapy, or air during air travel.
A modified version is performed by expiring against a closed glottis eliciting a cardiovascular response.
Because the maneuver increases intraocular pressure it can increase the risk of retinal detachment.
A normal response to Valsalva maneuver is an increased systolic blood pressure and pulse rate.
The normal physiological response to valsalva consists of four phases.
Initial pressure rises on the application of an expiratory force with pressure rising inside the chest forcing blood out of the pulmonary circulation into the left atrium.
The initial phase is associated with a mild rise in stroke volume.
Return of systemic blood to the heart is impeded by the pressure inside the chest by the Valsalva maneuver, and subsequently the output of the heart is reduced and stroke volume falls.
The fall in stroke volume occurs from 5 to about 14 seconds and reflexively causes blood vessels to constrict with some rise in pressure at 15 to 20 seconds.
Following this blood pressure returns to near or even above normal, but the cardiac output and blood flow to the body remains low as the pulse rate increases by compensatory tachycardia.
As the pressure on the chest is released, the pulmonary vessels and the aorta re-expand causing a further initial slight fall in stroke volume due to decreased left atrial return and increased aortic volume, respectively.
Venous blood can enter the chest and the heart, cardiac and output begins to increase.
As blood return to the heart is enhanced it causes a rapid increase in cardiac output at 24 seconds on, and stroke volume usually rises above normal before returning to normal.
When deviation from the above pattern occurs it signifies either abnormal heart function or abnormal autonomic nervous control of the heart.
Valsalva maneuver is commonly done either against a closed glottis, or against an external pressure measuring device, eliminating or minimizing the pressure on the Eustachian tubes.
Blowing against resistance as in blowing up balloons has a Valsalva effect.
Valsalva maneuver is often used on diving descent to equalize pressure in the middle ear to the ambient pressure.
May be used to arrest episodes of supraventricular tachycardia, and to diagnose heart abnormalities in conjunction with echocardiogram.
Valsalva maneuver increases the intensity of hypertrophic cardiomyopathy murmurs, and decreases the intensity of most other murmurs, including aortic stenosis and atrial septal defect.
The maneuver works by decreasing preload to the heart.
In the straining phase of the maneuver there is a reduction in the filling of the right and then the left side of the heart.
In the straining phase of the maneuver the stroke volume and blood pressure fall, while the heart rate increases.
The Valsalva maneuver can aid in the clinical diagnosis of problems or injury in the nerves of the cervical spine as it increases intraspinal pressure slightly.
Neuropathies and radicular pain may be felt or exacerbated by the VM and this may indicate impingement on a nerve by an intervertebral disc or other part of the anatomy.
The VM may cause headache and pain in the Arnold–Chiari malformation.
The Valsalva maneuver may be of use in checking for a dural tear following certain spinal operations as an increase in intra-spinal pressure will cause CSF to leak out of the dura causing a headache.
The procedure can be used used to aid diagnosis of intrinsic urinary sphincteric deficiency.
A Valsalva leak point in urodynamic terms refers to the minimum vesicular pressure that is associated with urine leakage.
Values > 60 cm H2O are commonly considered to indicate hypermobility of the bladder neck and normal sphincter function.
The maximum pelvic organ descent with pelvic organ prolapse can be demonstrated by the VM.
Valsalva retinopathy refers to a pathological finding of preretinal hemorrhage in individuals who have had a transient increase in the intrathoracic pressure associated with heavy lifting, forceful coughing, straining on the toilet, or vomiting.
The bleeding may cause visual loss if it obstructs the visual axis.