Pulmonary Edema: Overview and Practice Questions (2024)

Pulmonary edema is a medical condition characterized by the accumulation of excessive fluid in the lungs, leading to respiratory distress and impaired oxygen exchange.

This condition can be life-threatening and is often associated with underlying heart or lung problems.

Understanding the causes, symptoms, and treatment options for pulmonary edema is crucial for healthcare professionals and individuals alike, as prompt recognition and intervention can make a significant difference in patient outcomes.

What is Pulmonary Edema?

Pulmonary edema is a medical condition where fluid accumulates in the alveoli of the lungs, leading to difficulty breathing. This can result from heart problems, pneumonia, toxins, or trauma, leading to impaired gas exchange and oxygenation of the blood.

Causes

The causes of pulmonary edema are often categorized as cardiogenic and noncardiogenic.

Cardiogenic pulmonary edema is caused by increased pressures in the heart, such as from congestive heart failure (CHF).

Noncardiogenic causes include:

• Acute respiratory distress syndrome (ARDS)
• Kidney failure
• High altitude
• Infections
• Pulmonary embolism
• Narcotic overdose
• Neurogenic causes
• Inhalation of toxic gases
• Major injury

Note: Each cause leads to fluid leakage from the pulmonary capillaries into the alveoli, causing breathing difficulties.

Signs and Symptoms

The signs and symptoms of pulmonary edema can vary depending on the severity and the cause of the edema.

Common symptoms include:

• Hypoxemia
• Dyspnea
• Shortness of breath
• Tachypnea
• Tachycardia
• Pink, frothy secretions
• Orthopnea
• Diaphoresis
• Peripheral edema
• Jugular venous distention
• Crackles on auscultation
• Anxiety and restlessness
• Cyanosis

Note: These symptoms require prompt medical attention as pulmonary edema can be life-threatening.

Diagnosis

Diagnosing pulmonary edema typically involves a combination of clinical assessment and diagnostic tests.

Here’s how it’s generally approached:

• Medical History and Physical Examination: The doctor will review symptoms and medical history, looking for risk factors such as heart disease. During the physical exam, they’ll listen for abnormal heart or lung sounds with a stethoscope.
• Chest X-ray: This can show fluid accumulation in the lungs and may indicate the presence of pulmonary edema.
• Blood Tests: Arterial blood gas analysis can show low oxygen levels in the blood. Other blood tests can assess kidney function and cardiac enzymes.
• Echocardiogram: This ultrasound examination of the heart can determine if heart problems are causing pulmonary edema.
• Electrocardiogram (EKG): This test records the electrical activity of the heart and can identify abnormal rhythms and signs of heart strain.
• Pulmonary Artery Catheterization: Also known as a Swan-Ganz catheter, this may be used in severe cases to measure pressures in the heart and lungs.
• CT Scan: This imaging test provides detailed images of the lungs and can help in diagnosing the cause of pulmonary edema.

Prompt diagnosis and treatment of pulmonary edema are crucial to manage the underlying cause and prevent complications.

Treatment

Treatment of pulmonary edema focuses on improving respiratory function and treating the underlying cause.

Here are some common approaches:

• Oxygen Therapy: To increase blood oxygen levels, oxygen is given through a face mask or nasal prongs. In severe cases, mechanical ventilation may be needed.
• Noninvasive Ventilation: Such as continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) to maintain positive airway pressure and improve oxygenation without intubation.
• Mechanical Ventilation: Involves intubation and is used when noninvasive methods are insufficient to support the patient’s breathing.
• Medications: Diuretics for fluid removal, vasodilators to ease blood vessel pressure, inotropes to improve heart function, morphine for breathlessness and anxiety, and antihypertensives for high blood pressure.
• Preload Reducers: Reduce the amount of blood that goes to the heart, which can decrease work for the heart.
• Afterload Reducers: Lower the resistance against which the heart must pump.
• Positioning: Sitting the patient upright can help reduce the pressure in the chest and make breathing easier.
• Treatment of Underlying Causes: For instance, if a heart condition is causing edema, therapies will focus on managing heart health.
• Supportive Care: For cases caused by infection, antibiotics may be used; in toxin-related cases, antidotes may be necessary.

Note: This comprehensive approach is vital for effective treatment and may be adjusted based on the patient’s response and the progression of symptoms.

Types of Pulmonary Edema

Pulmonary edema can be classified into two primary types, each with distinct mechanisms and treatment considerations:

1. Cardiogenic Pulmonary Edema
2. Noncardiogenic Pulmonary Edema

Cardiogenic Pulmonary Edema

Cardiogenic pulmonary edema is caused by elevated pressures in the heart, commonly due to heart failure, where the heart cannot pump blood efficiently.

It leads to increased pressure in the pulmonary capillaries, forcing fluid into the alveoli, impairing gas exchange.

Treatment focuses on improving heart function and may include medications like diuretics to remove excess fluid, inotropes to strengthen the heart’s pumping ability, and vasodilators to decrease vascular resistance and workload on the heart.

Noncardiogenic Pulmonary Edema

In contrast, noncardiogenic pulmonary edema is not related to heart problems but rather results from increased permeability of the pulmonary capillary membrane due to direct or indirect lung injury.

Causes can include acute respiratory distress syndrome (ARDS), infections, inhalation of toxic gases, kidney failure, and more.

The treatment targets the underlying cause and may involve supportive measures like oxygen therapy, noninvasive or mechanical ventilation, and specific interventions for the precipitating condition, such as antibiotics for infections or antidotes for toxins.

Note: Understanding the type of pulmonary edema is crucial for effective treatment, as the strategies for managing cardiogenic and noncardiogenic pulmonary edema differ significantly based on their underlying causes.

Pulmonary Edema Practice Questions

1. What is the definition of pulmonary edema?
Pulmonary edema is a condition characterized by the accumulation of fluid in the lungs’ air sacs, leading to impaired gas exchange and breathing difficulty.

2. What major pathologic changes occur with pulmonary edema?
Interstitial edema, alveolar flooding, increased surface tension of alveolar fluids, alveolar shrinkage, atelectasis, and frothy pink secretions.

3. What is the most common cause of pulmonary edema?
Left-sided heart failure (i.e., congestive heart failure) is the most common cause of pulmonary edema.

4. When does left-sided heart failure occur?
It happens when the left ventricle is unable to pump out the proper amount of blood during contraction. As a result, pressure increases inside the left atrium and then in the pulmonary veins and capillaries, causing fluid to be pushed through the capillary walls into the alveoli.

5. What diastolic dysfunction occurs with pulmonary edema?
Poor ventricular function caused by increased stiffness or impaired myocardial relaxation.

6. How does pulmonary edema happen?
Hydrostatic pressure rises to more than 25-30 mmHg, oncotic pressure loses its hold, and fluid leaks into the interstitial space of the lungs.

7. What are the signs and symptoms of pulmonary edema?
The signs and symptoms of pulmonary edema typically include shortness of breath, especially when lying down, a feeling of suffocating, coughing up frothy sputum, excessive sweating, anxiety, and skin discoloration due to lack of oxygen.

8. What are the treatments for pulmonary edema?
Inotropic agents (e.g., Dobutamine, Dopamine, Norepinephrine), Diuretics, and noninvasive ventilation.

9. The presence of frothy pink secretions typically indicates what?
Pulmonary edema

10. What is the main cause of cardiogenic pulmonary edema?
Congestive heart failure (CHF)

11. What happens during cardiogenic pulmonary edema?
The left ventricle is unable to pump out all of the blood received from the lungs, causing the pulmonary vein/capillary blood pressure to increase. Then, fluid is pushed through capillary walls into the alveoli.

12. What determines the balance of pulmonary fluids?
Hydrostatic and oncotic pressures

13. What does hydrostatic pressure do?
It moves fluid out of the pulmonary capillaries into the interstitial space.

14. What does oncotic pressure do?
it draws fluid back in from the interstitial space.

15. When will fluid spill into the interstitial space?
When hydrostatic pressure rises above 25-30 mmHg

16. What are the properties of pulmonary edema?
Arrhythmias, congestive heart defects, excessive fluid administration, left ventricle failure, mitral or aortic valve disease, myocardial infarction, cardiac tamponade, pulmonary embolism, rheumatic heart disease (i.e., myocarditis), and cardiomyopathies.

17. What are the common causes of noncardiogenic pulmonary edema that increases capillary permeability?
Alveolar hypoxia, acute respiratory distress syndrome (ARDS), pneumonia, inhalation of toxic agents, pulmonary infections, therapeutic radiation of the lungs, excessive fluid administration, head injuries, lung transplant, lymphatic insufficiency, and obstructions caused by tumor cells.

18. What causes intrapleural pressures to decrease?
Severe airway obstruction

19. What may create a suction effect on the pulmonary capillaries, causing fluids to move into the alveoli?
The negative pressure exerted during inspiration.

20. When may fluid possibly seep into the interstitial and air spaces of the lung?
When the oncotic pressure drops below 10-15 mmHg.

21. Is Cheyne-Stokes respiration associated with pulmonary edema?
Cheyne-Stokes respiration, characterized by a gradual increase and then decrease in breathing depth followed by periods of apnea, can be associated with severe cases of pulmonary edema, often indicating an underlying heart condition. This is due to prolonged circulation time between the lungs and the central chemoreceptors.

22. What is orthopnea?
Shortness of breath while lying flat.

23. What position should patients with pulmonary edema be in and why?
Sitting upright due to fluid flooding.

24. What are some physical manifestations of pulmonary edema?
Cyanosis, cough, sputum (frothy pink), Cheyne-Stokes respirations, paroxysmal nocturnal dyspnea, orthopnea, and peripheral edema.

25. What chest assessment findings would you expect with pulmonary edema?
Increased tactile and vocal fremitus, crackles, rhonchi, and wheezing.

26. Which serum levels will be low in pulmonary edema?
Potassium and sodium

27. What is often seen in patients with left-sided heart failure and may result from diuretic therapy or excessive fluid retention?
Hypokalemia and hyponatremia

28. What can be observed on the chest x-ray of a patient with pulmonary edema?
Bilateral fluffy opacities, left ventricular hypertrophy (cardiomegaly), Kerley A and B Lines, pleural effusion, and batwing or butterfly pattern.

29. What is the general treatment of pulmonary edema based on?
The underlying etiology.

30. What respiratory care treatment protocols are used in pulmonary edema?
Oxygen therapy, bronchopulmonary hygiene, lung expansion therapy, CPAP, mechanical ventilation, hyperinflation therapy, and aerosolized medications.

31. What is used to reduce afterload by introducing venodilation and venous pooling that is also used for sedation and relief of anxiety?
Morphine sulfate

32. What drugs increase fluid removal?
Diuretic agents

33. What is used on an increased oncotic pressure in an effort to offset the increased hydrostatic forces of cardiac pulmonary edema?
Albumin and mannitol

34. How do fluids in pulmonary edema move?
Progressively from the pulmonary vascular system (i.e., pulmonary capillaries), perivascular and peribronchial interstitial spaces, alveoli, bronchi, and trachea, where the patient may cough it out.

35. What are the major pathologic or structural changes seen in the lungs with pulmonary edema?
Atelectasis, high surface tension of alveolar fluids, and alveolar flooding.

36. What are the available management strategies for cardiogenic pulmonary edema?
Low salt diet, lowering blood pressure, and increasing urine output with a diuretic medication.

37. What treatment should be given for cyanosis and shortness of breath for patients with pulmonary edema?
Supplemental oxygen therapy

38. Why is a CPAP used to treat pulmonary edema?
Because it decreases vascular congestion, reduces work of breathing, and improves lung compliance.

39. What will show on the chest radiograph of a patient with cardiogenic pulmonary edema?
Pleural effusion, cardiomegaly, and bilateral “butterfly” pattern fluffy infiltrates, among other findings.

40. What will show on the chest radiograph of a patient with noncardiogenic pulmonary edema?
Normal cardiac silhouette and fluffy densities near the hilum.

41. What is acute pulmonary edema considered?
It is considered to be a medical emergency.

42. What type of disease is pulmonary edema?
Restrictive disease

43. Where does fluid go in pulmonary edema?
Perivascular and peribronchial interstitial spaces.

44. What are the two major factors of pulmonary edema?
Hydrostatic pressure of 10-15 mmHg and colloid osmotic forces of 25-30 mmHg.

45. What happens when there is an increased hydrostatic pressure?
Fluid spills into the interstitial spaces and air spaces in the lungs.

46. What is the most common cause of pulmonary edema?
Increased pulmonary capillary hydrostatic pressure.

47. What are common cardiogenic causes of pulmonary edema?
Arrhythmias producing low cardiac output, congenital heart defects, renal failure, systemic hypotension, left ventricular failure, myocardial infarction, mitral or aortic valve disease, excessive fluid administration, cardiac tamponade, pulmonary embolus, cardiomegaly, and rheumatic heart disease-myocarditis.

48. What is the GOLD standard finding in pulmonary edema?
Greatly decreased residual volume.

49. Why is albumin used to treat pulmonary edema?
It does not cross the capillary membrane and will stay in the vascular system.

50. What is the normal value range for hydrostatic pressure?
10-15 mmHg

51. In noncardiogenic pulmonary edema, what are the causes of increased capillary permeability?
Alveolar hypoxia, acute respiratory distress syndrome (ARDS), inhalation of toxic agents, pulmonary infections, therapeutic radiation of the lungs, acute head injury, lymphatic insufficiency (slowed drainage), decreased intrapleural pressure, decreased oncotic pressure, over transfusion and/or rapid transfusion of IV fluids, uremia (i.e., blood in urine), hypoproteinemia (seen with severe malnutrition), acute nephritis, and polyarteritis nodosa.

52. What clinical manifestations are associated with pulmonary edema?
Atelectasis, increased alveolar-capillary membrane thickness, and excessive bronchial secretions.

53. What vital signs are associated with pulmonary edema?
Increased heart rate, respiratory rate, and blood pressure.

54. What PFT findings are associated with pulmonary edema?
Restrictive findings with decreased volumes and capacities.

55. What hemodynamic finding would you expect with pulmonary edema?
You can expect the pulmonary capillary wedge pressure (PCWP) to be increased.

56. What is the heart size of a patient with cardiogenic pulmonary edema?
Larger than normal

57. What is the heart size of a patient with noncardiogenic pulmonary edema?
Normal

58. What are the radiologic findings associated with noncardiogenic pulmonary edema?
Chest radiograph commonly shows areas of fluffy densities that are usually denser near the hilum. The infiltrates may be unilateral or bilateral.

59. What is the general treatment for cardiogenic and noncardiogenic pulmonary edema?
Treatment is based on the severity.

60. As a respiratory therapist, what is the general treatment for noncardiogenic pulmonary edema?
Largely supportive and aimed at ensuring adequate ventilation and oxygenation.

61. As a respiratory therapist, what is the general treatment for a patient with cardiogenic pulmonary edema?
Maintain the patient’s airway, oxygenation, and ventilation.

62. What are the three goals of treating cardiogenic pulmonary edema?
Reduction of pulmonary venous return (i.e., preload reduction), reduction of system vascular resistance (i.e., afterload reduction), and inotropic support.

63. What inotropic agents are given for cardiogenic pulmonary edema?
Dobutamine, dopamine, norepinephrine, and milrinone.

64. What are the other agents used in the general management of cardiogenic pulmonary edema?
Antidysrhythmic agents, bradycardia (atropine), tachycardia (procainamide, metoprolol, bretylium), and albumin or mannitols are used to increase the patient’s oncotic pressure.

65. What is the progression of pulmonary edema?
Pulmonary edema progresses from increased pulmonary capillary pressure with mild symptoms to severe fluid accumulation in the lungs’ air spaces, leading to significant respiratory distress and impaired oxygenation.

Final Thoughts

Pulmonary edema is a medical emergency that demands swift and accurate diagnosis and treatment.

As medical professionals, understanding the underlying causes, recognizing the clinical signs and symptoms, and employing appropriate diagnostic tools and therapeutic interventions are vital in improving patient outcomes.

By staying informed and prepared, healthcare providers can play a crucial role in managing pulmonary edema and providing the best possible care to patients facing this life-threatening condition.