What lung sounds are typically heard in a patient with heart failure and suspected Acute Pulmonary Edema (APO)?

From the Guidelines

In patients with heart failure and suspected acute pulmonary edema (APO), the most characteristic lung sounds are crackles (also called rales), which are typically bilateral and heard predominantly in the lung bases but can extend upward as the condition worsens. These crackles are fine, high-pitched, discontinuous sounds that occur when previously collapsed alveoli suddenly reopen during inspiration as air moves through fluid-filled airways. According to the 2016 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 1, symptoms and signs of congestion, such as orthopnoea, paroxysmal nocturnal dyspnoea, and pulmonary rales, are key indicators of acute heart failure. Wheezing may also be present, particularly in patients with cardiac asthma, a variant of APO. As the condition progresses, rhonchi (low-pitched continuous sounds) might be audible due to secretions in larger airways. Decreased breath sounds may occur in areas where air movement is significantly compromised by fluid accumulation. These abnormal lung sounds develop because left-sided heart failure causes increased pulmonary venous pressure, leading to fluid leakage into the alveolar spaces. This fluid accumulation interferes with normal gas exchange and produces the characteristic sounds during auscultation. The severity and extent of these abnormal lung sounds typically correlate with the degree of pulmonary edema. It is essential to note that the initial diagnosis of AHF should be based on a thorough history and physical examination, including the assessment of signs and symptoms of congestion and/or hypoperfusion, as recommended by the 2016 ESC guidelines 1. Additionally, the 2015 recommendations on pre-hospital and early hospital management of acute heart failure suggest that bedside thoracic ultrasound can be useful for signs of interstitial edema 1. However, the most recent and highest quality study, the 2016 ESC guidelines 1, prioritizes the clinical evaluation and the assessment of symptoms and signs of congestion, including pulmonary rales, for the diagnosis of AHF. Therefore, the presence of bilateral crackles or rales is a critical finding in patients with heart failure and suspected APO, and it should be considered a key indicator of the condition, along with other symptoms and signs of congestion. In clinical practice, it is crucial to prioritize the assessment of these lung sounds, as they can provide valuable information about the severity of pulmonary edema and guide further management. The use of additional investigations, such as chest X-ray and echocardiography, can also be helpful in confirming the diagnosis and assessing the severity of the condition, but the clinical evaluation, including the assessment of lung sounds, remains the cornerstone of diagnosis and management.

From the Research

Lung Sounds in Heart Failure with Suspected Acute Pulmonary Edema (APO)

• The lung sounds typically heard in patients with heart failure and suspected Acute Pulmonary Edema (APO) include crackles or rales, which are abnormal sounds heard upon auscultation of the lungs 2.
• These sounds are often described as bubbling, rattling, or crackling sounds and are usually heard over the lower lung fields 3.
• The presence and severity of crackles can be an indicator of the severity of pulmonary edema and can be used to monitor the patient's response to treatment 4.
• Other lung sounds that may be heard in patients with heart failure and suspected APO include wheezes, rhonchi, and pleural rubs, although these are less common 5.
• The use of automated analysis of lung sounds, such as crackle analysis, may help to distinguish between different causes of lung sounds, including heart failure, interstitial pulmonary fibrosis, and pneumonia 5.

Characteristics of Lung Sounds in APO

• The crackles heard in patients with APO are often coarse and may be heard over a large area of the lung field 2.
• The sounds may be more pronounced over the lower lung fields and may be accompanied by other signs of pulmonary edema, such as orthopnea and paroxysmal nocturnal dyspnea 3.
• The severity of the crackles can be correlated with the severity of the pulmonary edema and the patient's overall clinical condition 4.

Clinical Significance of Lung Sounds in APO

• The presence and characteristics of lung sounds in patients with heart failure and suspected APO can provide important clues to the diagnosis and severity of the condition 2.
• The use of lung sound analysis, in combination with other clinical findings and diagnostic tests, can help to guide treatment and monitor the patient's response to therapy 3, 4.
• The early recognition and treatment of APO are critical to improving patient outcomes and reducing the risk of complications, such as respiratory failure and cardiac arrest 6, 3.