What causes orthopnea?
In general, shortness of breath (dyspnea) is a common symptom of congestive heart failure. This is because increased fluid in the lungs can interfere with the exchange of oxygen, resulting in not enough oxygen reaching the tissues, This is most typically noticed during exercise, but it can also occur when a person is lying down -- that's when it's called orthopnea.
Orthopnea can be a subtle condition, in which a person notices that sleep is more comfortable with several pillows under his head, or a more severe one in which he can breathe deeply and comfortably only when sitting or standing. It may occur along with swelling of the feet or ankles. Orthopnea is a sign of heart failure. It is caused by congestion in the lungs -- and perhaps accompanied by accumulation of excess fluid in the lungs (pulmonary edema) -- that occurs as a result of left-sided heart failure.
Orthopnea is caused by the accumulation of too much fluid in the lungs (pulmonary congestion or fluid overload) when a person lies down. In a prone position, blood volume from the feet and legs redistributes to the lungs, which doesn't cause a problem for people whose hearts are pumping normally. However, in people with heart failure, excess blood in the lungs can cause breathing problems or shortness of breath.
Fluid Overload Treatment
If excess fluid is causing breathing problems like orthopnea or paroxysmal nocturnal dyspnea, doctors may recommend that the patient eat a low-sodium diet, because too much sodium can contribute to fluid overload. They may also prescribe diuretics (sometimes called "water pills"), medicines that help the body eliminate excess sodium and water. However, diuretics sometimes become less effective over time, so after awhile, many people with fluid overload must be hospitalized for additional treatment.
This treatment can include intravenous medications like loop diuretics, vasodilator drugs (medicines that increase the diameter of blood vessels so blood flow is increased) and inotropic drugs (medicines that cause the heart to pump more blood with each contraction).
If these medicines don't work to relieve the fluid overload, doctors may prescribe a procedure known as ultrafiltration, in which blood is passed through a small machine that filters out the excess fluid.
Related HowStuffWorks Articles
- How Your Heart Works
- How Your Lungs Work
- How Your Kidneys Work
- How Blood Works
- How Ultrafiltration Works
- Is there a link between heart disease and kidney disease?
- What are the symptoms of heart failure?
- How Vasodilator Drugs Work
- How Fluid Overload and Edema Work
- How Jugular Venous Distension Works
- How does heart failure affect quality of life?
- How Inotropic Drugs Work
- How Diuretics Work
- How Low-Sodium Diets Work
More Great Links
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