The Valsalva maneuver or Valsalva manoeuvre is performed by forcible exhalation against a closed airway, usually done by closing one's mouth and pinching one's nose shut. 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 or aviation.
The technique is named after Antonio Maria Valsalva,[1] 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 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:[2]
- 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 stroke volume.
- 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 stroke volume falls. This occurs from 5 to about 14 seconds in the illustration. The fall in stroke volume 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.
- 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 stroke volume (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.
- 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 (24 seconds on). The stroke volume 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 dentists 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.[3][4][5] 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.[4][6][7][8] 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.[4] 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.
In a clinical setting the Valsalva maneuver will commonly be done either against a closed glottis, or against an external pressure measuring device, thus eliminating or minimizing the pressure on the Eustachian tubes. Straining or 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.[9][10] The maneuver can sometimes be used to diagnose heart abnormalities, especially when used in conjunction with echocardiogram.[11] 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 most other murmurs, including aortic stenosis and atrial septal defect.
The Valsalva maneuver alters heart rate through parasympathetic stimulation (i.e. the vagus nerve, cranial nerve X). Vagal neuro-muscular junctions at the sinoatrial node release the neurotransmitter acetylcholine (ACh). Ligand-receptor binding causes several effects:
1. ACh lowers the permeability of muscle cell membranes to sodium and calcium ions, resulting in a slower rate of pacemaker depolarization. Hence, the cell takes longer to generate an action potential.
2. ACh also lowers the number of available L-type calcium channels, which elevates the cell's threshold for action potentials. Thus, the cell needs to depolarize more than normal to fire an action potential.
3. New research suggests that ACh also activates latent potassium channels in the cell membrane. Increased potassium ion influx decreases the maximum diastolic potential of the cell. That is, hyperpolarization decreases the membrane potential of the pacemaker cells.
These effects elongate the time between pacemaker action potentials, which results in a slower heartbeat and a mechanism to interrupt or diagnose arrhythmia. In later phases of the Valsalva maneuver (phases II and III), heart rate elevates due to sympathetic interplay.
Neurology
The Valsalva maneuver is used to aid in the clinical diagnosis of problems or injury in the nerves of the cervical spine.[12] 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.[13] 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.
See also
References
- ^ synd/2316 at Who Named It?
- ^ Luster EA, Baumgartner N, Adams WC, Convertino VA (April 1996). "Effects of hypovolemia and posture on responses to the Valsalva maneuver". Aviat Space Environ Med 67 (4): 308–13. PMID 8900980.
- ^ Brubakk, A. O.; T. S. Neuman (2003). Bennett and Elliott's physiology and medicine of diving, 5th Rev ed.. United States: Saunders Ltd.. pp. 800. ISBN 0702025712.
- ^ a b c Kay, E. "Prevention of middle ear barotrauma" (html). http://faculty.washington.edu/ekay/MEbaro.html. Retrieved 2008-06-11.
- ^ Kay, E. "The Diver's Ear - Under Pressure" (Flash video). http://faculty.washington.edu/ekay/. Retrieved 2008-06-11.
- ^ Roydhouse, N (1978). "The squeeze, the ear and prevention". South Pacific Underwater Medicine Society journal 8 (1). ISSN 0813-1988. OCLC 16986801. http://archive.rubicon-foundation.org/6169. Retrieved 2008-06-11.
- ^ Taylor, D (1996). "The Valsalva Manoeuvre: A critical review". South Pacific Underwater Medicine Society journal 26 (1). ISSN 0813-1988. OCLC 16986801. http://archive.rubicon-foundation.org/6264. Retrieved 2008-06-11.
- ^ Roydhouse, N and Taylor, D (1996). "The Valsalva Manoeuvre. (letter to editor)". South Pacific Underwater Medicine Society journal 26 (3). ISSN 0813-1988. OCLC 16986801. http://archive.rubicon-foundation.org/6303. Retrieved 2008-06-11.
- ^ Lim SH, Anantharaman V, Teo WS, Goh PP, Tan AT (January 1998). "Comparison of treatment of supraventricular tachycardia by Valsalva maneuver and carotid sinus massage". Ann Emerg Med 31 (1): 30–5. doi:10.1016/S0196-0644(98)70277-X. PMID 9437338.
- ^ Nagappan R, Arora S, Winter C (June 2002). "Potential dangers of the Valsalva maneuver and adenosine in paroxysmal supraventricular tachycardia--beware preexcitation". Crit Care Resusc 4 (2): 107–11. PMID 16573413.
- ^ Zuber M, Cuculi F, Oechslin E, Erne P, Jenni R (June 2008). "Is transesophageal echocardiography still necessary to exclude patent foramen ovale?". Scand. Cardiovasc. J. 42 (3): 222–5. doi:10.1080/14017430801932832. PMID 18569955. http://www.informaworld.com/openurl?genre=article&doi=10.1080/14017430801932832&magic=pubmed. Retrieved 2008-07-09.
- ^ Johnson RH, Smith AC, Spalding JM (February 1969). "Blood pressure response to standing and to Valsalva's manoeuvre: independence of the two mechanisms in neurological diseases including cervical cord lesions". Clin Sci 36 (1): 77–86. PMID 5783806.
- ^ Gibran SK, Kenawy N, Wong D, Hiscott P (May 2007). "Changes in the retinal inner limiting membrane associated with Valsalva retinopathy". Br J Ophthalmol 91 (5): 701–2. doi:10.1136/bjo.2006.104935. PMID 17446519. http://bjo.bmj.com/cgi/pmidlookup?view=long&pmid=17446519. Retrieved 2008-07-09.
This orthopedic test also can be a positive for a SOL/ space occupying lesion, e.g. Tumor (benign or malignant), clot, or anything taking up space where there is normally no space to be occupied.
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