Orthopnea or orthopnoea is

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

(dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

, resulting from

fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...

redistribution into the central circulation, causing an increase in pulmonary capillary pressure and causing difficulty in breathing. It is also seen in cases of

abdominal obesity Abdominal obesity, also known as central obesity and truncal obesity, is a condition when excessive visceral fat around the stomach and abdomen has built up to the extent that it is likely to have a negative impact on health. Abdominal obesity h ...

or pulmonary disease. Orthopnea is the opposite of platypnea, shortness of breath that worsens when sitting or standing upright.

Causes

Orthopnea is often a symptom of left ventricular

and/or cardiogenic

pulmonary edema Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due ...

. It can also occur in those with

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

and chronic

bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...

, as well as those with

sleep apnea Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many tim ...

panic disorder Panic disorder is a mental and behavioral disorder, specifically an anxiety disorder characterized by reoccurring unexpected panic attacks. Panic attacks are sudden periods of intense fear that may include palpitations, sweating, shaking, short ...

. It is also as associated with polycystic liver disease. From a neuromuscular perspective, orthopnea is potentially a sign of severe diaphragmatic weakness. Under such circumstances, patients may describe shortness of breath when they bend over (e.g. when tying shoelaces), called bendopnea.

Mechanism

Orthopnea is due to increased distribution of blood to the

pulmonary circulation The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs ...

when a person lies flat or closer to a horizontal position. Lying flat decreases the inhibitory effect that the gravity usually has on the blood when coming back to the heart from the lower extremities of the body. This increases the right sided venous return. In a normal person, this redistribution of blood has little effect on respiratory function as the left ventricle has the adequate capacity to suddenly increase its stroke volume (as a result of the Frank-Starling mechanism). In a person with

, the left ventricle has an inadequate capacity to respond to increased arrival of blood from the pulmonary circulation. This leads to the pooling up of blood in the pulmonary circulation and doesn't change its volume enough. The increased intra-parenchymal pulmonary intravascular pressure can also result in hydrostatic pressure related fluid transudation into the

alveoli Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * M ...

, thus causing cardiogenic

and further worsening shortness of breath. Thus, shortness of breath is commonly experienced after a reasonably short time lying near to flat for a person with left ventricular failure. This is different from the dyspnea experienced by someone with lung parenchymal pathology (both restrictive and obstructive) when lying down, which is sudden and instead related to an acute change in diaphragmatic/accessory respiratory muscle mechanical advantage lost when moving the body into a more horizontal position.

Diagnosis

Diagnosis is based mostly on the clinical features and symptoms, as well as finding causes like heart failure.

Treatment

Based on the cause, Orthopnea can be treated with respiratory support devices such as CPAP or biPAP while the disease causing it is addressed.

Etymology

The word ''orthopnea'' uses combining forms of '' ortho-'' + '' -pnea'', from

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''ortho'', straight, regular, + ''pnoia'', breath. See pronunciation information at ''dyspnea''.

References

External links

Breathing abnormalities {{respiratory-disease-stub