Orthopnea

Synonyms

Dyspnoea with the patient lying down; dyspnoea with the patient lying down;

Definition

Orthopnea refers to pronounced dyspnea that occurs exclusively in a recumbent position (Kasper 2015 / Siegenthaler 2006) and can only be eliminated by an upright posture and by using the respiratory support muscles (Lohr 2002).

Orthopnea represents the late manifestation of dyspnea in the context of heart failure (Kasper 2015).

Shortness of breath due to heart failure occurs:

• in the family practice with approx. 5.4 % in 5th place (the places 1 - 4 are occupied by respiratory causes)
• in the ambulance service on the 1st place with 15 - 16 %
• in the emergency room in 2nd place with approx. 16.1 % (Berliner 2016).

Orthopnea is found in

• Heart failure especially in congestive heart failure (CHF [Kasper 2015]).

The sensitivity of orthopnea with respect to heart failure is 42.8%, and the specificity is 87.51%. The positive predictive value is 14.5%, and the negative is 96.9% (Dennis 2019).

• mechanical impairment of the diaphragm due to e.g.
  • Obesity
  • Bronchial asthma (Kasper 2015)
  • Tumors (Shikino 2020)
  • bilateral paresis of the diaphragm (Oranen 1999) due to e.g.
    • Amyotrophic lateral sclerosis
    • Multiple sclerosis
    • Spinal disorders (Dennis 2019)
  • Ascites
  • extensive pleural effusions (Siegenthaler 2005)
  • Chronic obstructive pulmonary disease (Dennis 2019)

Orthopnea results from redistribution of fluid from the splanchnic circulation and lower extremities to the central circulation (Kasper 2015).

Heart failure

This extra volume of blood cannot be pumped on effectively with impaired left ventricular function. This results in an increase in pressure around the left ventricle, left atrium and pulmonary capillary occlusion. As a result:

• pulmonary edema develops
• the airway resistance increases
• lung compliance is reduced
• the pulmonary receptors are stimulated
• the vital capacity decreases
• occlusion of the small airways and so-called air trapping occurs
• Due to the altered distribution of ventilation and perfusion, there is:
  • widening of the alveolar-arterial oxygen gradient
  • Hypoxemia
  • enlargement of the dead space
• The oedematous swelling of the bronchial wall causes an occlusion of the small airways and thus causes the typical wheezing of cardiac asthma.
• increasing limitation of expiratory airflow
• Increase in energy expenditure in the diaphragm to counteract the restrictive loads on the lungs (this must be overcome by the inspiratory muscles)

(Dennis 2019)

Mechanical impairment of the diaphragm.

When the diaphragm is mechanically impaired, lung dynamics are found to be favored by the upright posture (Kasper 2015).

Bilateral diaphragmatic paresis.

In bilateral diaphragmatic paresis, there is a cranial shift of the abdominal contents in the supine position. This causes the residual volume to decrease. Since the diaphragm cannot contract, the abdominal contents cannot shift caudally either (Dennis 2019).

Chronic obstructive pulmonary disease

In COPD, increased inspiratory effort occurs in the supine position due to increased airway resistance and intrinsic PEEP.

Premature airway closure, destruction of lung architecture, airway collapse at rest, and increased airway resistance limit expiratory airflow. Dynamic hyperinflation of the lungs develops as a result.

Intrinsic positive end-expiratory pressure thus occurs, requiring increased inspiratory work of breathing. The supine position increases flow restriction and airway resistance increases (Dennis 2019).

• Coughing at night (typical symptom [Kasper 2015])
• Feeling like breathing through a straw (Jang 2019)
• Improvement of symptoms after sitting up or standing up within a few minutes

The typical posture of a heart failure patient is to elevate the upper body while sleeping, and the degree of elevation is a good indication of the severity of heart failure. Therefore, the patient should be asked about the number of pillows they need when sleeping (Siegenthaler 2005).

Orthopnea occurs with a time delay in the case of heart failure, but in the case of mechanical impairment of the diaphragm, orthopnea occurs immediately after lying down (Shikino 2020).

Orthopnea also occurs very rapidly in bilateral diaphragmatic palsy. In addition, paradoxical abdominal movements are still found (Dennis 2019).

Further diagnosis depends on the suspected diagnosis.

• paroxysmal nocturnal dyspnoea

This is caused by an intrapulmonary, intraalveolar edema, often with an additional bronchospasm. After raising the upper body, there is no immediate improvement in orthopnea - as in heart failure - but usually only after expectoration of the secretions (Siegenthaler 2005).

• Bronchial asthma

In contrast to heart failure, there is no improvement in orthopnoea in bronchial asthma after raising the upper body.

Acute orthopnea can be alleviated immediately by sitting up or standing up. Sleeping with the upper body elevated also leads to an improvement in symptoms (Kasper 2015).

Further therapeutic measures depend on the cause of the disease.

The prognosis depends on the underlying disease.

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