What sounds are heard in pulmonary edema secondary to heart failure?

From the Guidelines

In pulmonary edema secondary to heart failure, the characteristic sounds heard on auscultation include fine crackles (also called rales), which typically begin at the lung bases and may progress upward as the condition worsens. These crackles sound like pieces of hair being rubbed together near your ear and result from air moving through fluid-filled alveoli.

Characteristic Sounds

• Fine crackles (also called rales)
• Wheezing due to bronchial compression from interstitial edema
• A third heart sound (S3 gallop) indicating ventricular dysfunction and volume overload
• Decreased breath sounds at the lung bases due to pleural effusion
• Rhonchi or coarse crackles if secretions are present in the larger airways These sounds occur because heart failure leads to increased left ventricular filling pressures, which back up into the pulmonary circulation, forcing fluid into the alveolar spaces, as noted in the guidelines for the diagnosis and treatment of acute and chronic heart failure 1.

Diagnostic Considerations

The European Society of Cardiology guidelines highlight the importance of physical examination in diagnosing heart failure, including the presence of distended neck veins, paradoxical pulse, and muffled heart sounds 1.

Recent Findings

Recent studies have also emphasized the role of lung ultrasound in diagnosing pulmonary edema, with a good sensitivity and specificity 1.

Clinical Implications

Prompt recognition of these auscultatory findings is crucial for early intervention with diuretics, oxygen therapy, and treatment of the underlying cardiac dysfunction, as emphasized in the guidelines for the diagnosis and treatment of acute heart failure 1.

From the Research

Sounds Heard in Pulmonary Oedema

• Pulmonary oedema is a life-threatening emergency that requires immediate intervention, and its presentations can include various sounds heard during physical examination 2.
• The sounds heard in pulmonary oedema secondary to heart failure are often referred to as "rales" or pulmonary crackles, which are a common finding in acute heart failure (AHF) 3.
• Rales are an essential inclusion criterion in most AHF trials, based on findings on physical examination or radiographic criteria, and their prevalence in HF-REF trials ranges from 75% to 83% 3.
• The presence of rales over >2/3 of the lung fields on admission may be associated with a higher risk of adverse outcomes 3.
• Age-related pulmonary crackles (rales) can also be present in asymptomatic cardiovascular patients, and their prevalence increases with age, approximately threefold every 10 years after 45 years of age 4.
• The short-term reproducibility of crackles is high, at 87%, and recognition of age-related pulmonary crackles is important to avoid interference with the physician's management of cardiopulmonary patients 4.

Pathophysiology of Pulmonary Oedema

• Pulmonary oedema is defined as an increase in extravascular water content of the lungs, which cannot occur until the rate of fluid filtration exceeds the rate of lymphatic removal 5.
• Two main types of pulmonary oedema are recognized: cardiogenic (or hydrostatic) pulmonary oedema from elevated pulmonary capillary pressure, and noncardiogenic (increased permeability) pulmonary oedema from injury to the endothelial and epithelial barriers 5.
• Cardiogenic pulmonary oedema is often associated with left-sided heart failure, and its diagnosis and management are critical in patients with suspected heart failure 2, 3.