Assessing Fluid in the Lungs During Auscultation Illustration

Assessing Fluid in the Lungs During Auscultation (2024)

by | Updated: Apr 22, 2024

Auscultation, the process of listening to the sounds produced within the body, is an essential aspect of clinical assessment in respiratory medicine.

Fluid accumulation in the lungs, a manifestation of conditions like heart failure, pneumonia, or pulmonary edema, can have profound clinical implications.

Detecting these changes early through auscultation can significantly impact patient outcomes and guide subsequent medical interventions.

This article delves into the nuances of identifying fluid in the lungs during auscultation, emphasizing the importance of starting at the lower lung fields to ascertain the presence and extent of fluid accumulation.

How to Assess Fluid in the Lungs During Auscultation?

When assessing for fluid collection in the lungs during auscultation of lung sounds, you should start at the lower lung fields and determine at which level you start hearing clear breath sounds. Listen for characteristic crackles or rales, indicating fluid. Compare both sides symmetrically to distinguish between unilateral or bilateral accumulation, guiding diagnosis and intervention.

Auscultation Stethoscope with Fluid in Lungs Vector

What is Auscultation?

Auscultation is the medical practice of listening to the internal sounds of the body using a stethoscope. It is primarily used to assess the functioning of the heart, lungs, and occasionally the gastrointestinal system.

This diagnostic technique allows healthcare professionals to detect and assess abnormalities in organ function, such as heart murmurs or altered lung sounds.

Auscultation is a fundamental component of the physical examination and offers valuable insights into a patient’s health status without the need for invasive procedures or advanced imaging.

Causes of Fluid in the Lungs

Fluid accumulation in the lungs can be caused by a variety of conditions, including the following:

  • Pulmonary Edema: Fluid buildup in the lung’s air spaces and interstitium, often due to heart failure or factors unrelated to heart function, such as infections or toxins.
  • Congestive Heart Failure (CHF): When the heart is unable to pump blood efficiently, it can lead to a buildup of pressure and fluid leakage into the lungs.
  • Pneumonia: Infection in the lungs can lead to inflammatory responses that cause fluid to accumulate in the alveoli.
  • Acute Respiratory Distress Syndrome (ARDS): A severe lung condition causing widespread inflammation and fluid buildup in the lungs.
  • Hemothorax: Accumulation of blood in the pleural cavity, typically resulting from chest trauma, surgery, or conditions like pulmonary embolism. It can compress the lungs and impair respiratory function.
  • Kidney Disease: Kidneys play a role in regulating fluid balance in the body. Severe or chronic kidney disease can lead to fluid buildup, including in the lungs.
  • High Altitude Pulmonary Edema (HAPE): This can occur when individuals rapidly ascend to high altitudes, leading to fluid accumulation in the lungs.
  • Pulmonary Embolism: A blood clot in the lungs can lead to increased pressure and fluid leakage into the lung tissue.
  • Lung Injury: Trauma or damage to the lung tissue can result in fluid leakage.
  • Lymphatic Obstruction: Conditions like lymphangitis or tumors can block the lymphatic system, causing fluid to build up in the lungs.
  • Certain Medications: Some drugs, especially certain chemotherapy agents, can cause fluid accumulation in the lungs as a side effect.
  • Viral Infections: Some viral infections can lead to fluid buildup in the lungs.
  • Near Drowning: Inhaling water can cause fluid to accumulate in the lungs.
  • Smoke Inhalation: Exposure to significant amounts of smoke, such as in a house fire, can lead to inflammation and fluid buildup.
  • Toxic Inhalation: Breathing in harmful chemicals or irritants can result in lung injury and subsequent fluid accumulation.

Note: While these conditions can cause fluid in the lungs, the clinical presentation, underlying mechanisms, and treatments can vary widely. Proper diagnosis and management are vital to address the root cause and prevent complications.

What is Pulmonary Edema?

Pulmonary edema is a condition characterized by the accumulation of fluid in the air spaces (alveoli) and the interstitial space of the lungs.

This fluid buildup can interfere with gas exchange, leading to difficulty breathing and reduced oxygenation of the blood.

The two primary types of pulmonary edema include:

  1. Cardiogenic: Caused by increased pressure in the heart, often due to heart failure. In this scenario, the heart cannot pump blood efficiently, leading to increased pressure in the pulmonary blood vessels, which in turn causes fluid to leak into the lung tissue.
  2. Non-cardiogenic: Not directly related to heart function. Causes can include lung infections, exposure to certain toxins, severe trauma, some medications, high altitudes, or acute respiratory distress syndrome (ARDS).

Symptoms of pulmonary edema include shortness of breath, difficulty breathing (especially when lying flat), coughing, wheezing, and a feeling of suffocation or drowning. Immediate medical attention is essential, as severe pulmonary edema can be life-threatening.

Treatment depends on the cause and may include oxygen therapy, medications, and other interventions to alleviate symptoms and address the underlying condition.

Lung Sounds Heard When Fluid is Present

When fluid is present in the lungs, it can alter the sounds heard during auscultation. Here are some of the characteristic lung sounds associated with fluid accumulation:

  • Crackles (Rales): These are discontinuous, high-pitched sounds reminiscent of hair being rolled between fingers near the ear or Velcro being pulled apart. Fine crackles are short-duration, high-pitched sounds heard during the end of inspiration, often linked to interstitial pulmonary edema, pneumonia, or fibrosis. In contrast, coarse crackles are louder, lower in pitch, and last longer, heard earlier in inspiration and commonly associated with bronchitis, bronchiectasis, or early congestive heart failure.
  • Rhonchi: These are continuous, low-pitched rattling sounds similar to snoring or gurgling. They can sometimes clear with coughing and are often caused by obstruction or secretions in larger airways. When associated with fluid, they can indicate conditions like pulmonary edema with larger airway involvement or chronic bronchitis.
  • Wheezing: While typically associated with narrowed airways from asthma, COPD, or bronchitis, wheezing (continuous high-pitched sounds) can occasionally be heard if there’s significant fluid-related narrowing of the airways.
  • Pleural Friction Rub: While not directly a sound of fluid within the lung parenchyma, this sound can be heard when there’s inflammation of the pleura (pleurisy), which can be due to fluid accumulation in the pleural space (like in pleural effusion). It sounds like two pieces of leather rubbing together and is heard during both inspiration and expiration.
  • Decreased or Absent Breath Sounds: If there’s a significant amount of fluid, such as in a large pleural effusion, breath sounds may be decreased or even absent in the affected area.

Note: While these sounds can indicate fluid in the lungs, they can also be present in other conditions. Clinical context, patient history, and other physical examination findings should be used in conjunction to arrive at an accurate diagnosis.

FAQs About Fluid in the Lungs and Auscultation

Can Fluid in the Lungs Be Heard Without a Stethoscope?

Yes, in certain cases, fluid in the lungs can produce sounds audible without a stethoscope.

For instance, individuals with severe pulmonary edema or advanced stages of certain respiratory diseases may exhibit audible wheezing or crackles, especially during exertion or when lying down.

However, a stethoscope significantly amplifies these sounds, allowing for earlier detection and a more detailed assessment.

How Do You Listen for Fluid in Your Lungs with a Stethoscope?

To listen for fluid in the lungs using a stethoscope:

  1. Have the person sit upright, exposing their back.
  2. Place the stethoscope’s diaphragm on the bare skin, starting at the lower lung fields near the bases.
  3. Listen systematically, moving the stethoscope upwards and towards the mid and upper lung fields.
  4. Note any abnormal sounds, especially crackles (rales), which indicate fluid.
  5. Compare sounds between the left and right lungs for symmetry.

What Breath Sound Indicates Fluid in the Lungs?

The primary breath sound that indicates fluid in the lungs is referred to as “crackles” or “rales.” These are discontinuous, popping sounds that can be heard primarily during inspiration.

Crackles can be categorized as fine or coarse, with fine crackles being more indicative of conditions like interstitial pulmonary edema.

Coarse crackles, on the other hand, suggest fluid in larger airways or early stages of conditions like bronchitis or congestive heart failure.

What Do You Hear on Auscultation with a Pleural Effusion?

During auscultation of a pleural effusion, breath sounds are typically decreased or absent over the area where the effusion is present due to the liquid hindering lung expansion.

Additionally, if the effusion is large enough, percussion of the chest may produce a dull sound.

What Does Pulmonary Edema Sound Like with a Stethoscope?

Pulmonary edema primarily produces crackles or rales during auscultation. These crackles can be heard predominantly during the end of inspiration and sometimes at the beginning of expiration.

The sounds are due to the popping open of small airways and alveoli that were previously closed due to the presence of fluid.

Depending on the severity and location of the fluid, the crackles can range from fine (high-pitched) to coarse (lower-pitched).

What is the Best Stethoscope for Auscultation?

While the choice of stethoscope can be influenced by personal preference, setting, and specific patient populations, the 3M Littmann Classic III Monitoring Stethoscope is highly regarded in the medical community.

It offers clear acoustics, durability, and versatility, suitable for a wide range of clinical settings.

The dual-sided chest piece, tunable diaphragms, and comfortable ear tips make it a preferred choice for many healthcare professionals seeking reliable auscultation tools.

Our Top Pick
3M Littmann Classic III Monitoring Stethoscope

This is our top recommendation due to its exceptional acoustic performance, durable construction, and versatility for both adult and pediatric patients, making it a reliable choice for healthcare professionals.

If you click this link and make a purchase, we earn a commission at no additional cost to you.

Final Thoughts

Auscultation is an essential process for diagnosing and monitoring respiratory conditions in clinical practice.

Recognizing the distinct sounds associated with fluid accumulation in the lungs can guide healthcare professionals toward an accurate diagnosis and appropriate intervention.

As always, these auditory clues should be interpreted in conjunction with a patient’s overall clinical presentation and other diagnostic tests.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Sarkar M, Madabhavi I, Niranjan N, Dogra M. Auscultation of the respiratory system. Ann Thorac Med. 2015.
  • Zimmerman B, Williams D. Lung Sounds. [Updated 2022 Aug 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.

Recommended Reading