Adventitious lung sounds: a guide for nursing students

Auscultating the lungs is one of the most clinically informative skills you will use every shift. Adventitious lung sounds — sounds heard in addition to normal breath sounds — tell you that something is wrong in the airways, lung parenchyma, or pleural space. Catching a new wheeze, a sudden onset of stridor, or bilateral basal crackles in a post-op patient can change the entire trajectory of your care plan. This guide covers all five major types of adventitious sounds, how to identify each one, what conditions they signal, and when you need to escalate immediately.

Quick-reference table: adventitious lung sounds

Detailed breakdown of each sound type

Crackles (fine and coarse)

Crackles are discontinuous, interrupted sounds generated when small collapsed airways snap open during inhalation. They are not caused by air moving through fluid, as many students first assume — the popping arises from the sudden opening of airways that were held shut by surface tension or secretions.

Fine crackles are soft, high-pitched, and occur in late inspiration. Clinically they sound similar to separating a strip of Velcro or rubbing strands of hair between your fingers near your ear. They are heard predominantly at the lung bases because the dependent zones of the lung are most prone to alveolar collapse. Fine crackles clear poorly with coughing because they originate in the small airways and alveoli, not the large airways.

Conditions associated with fine crackles include:

• Early and moderate heart failure (fluid accumulation in the alveolar space)
• Idiopathic pulmonary fibrosis (IPF) — the “velcro crackles” of IPF are late-inspiratory and bilateral, often heard at the bases in patients over 60
• Early pneumonia — see pneumonia nursing for a full clinical picture
• Atelectasis — particularly post-operative patients who have been breathing shallowly

Coarse crackles are louder, lower-pitched, and occur earlier in inspiration. They arise from larger airways and have a wet, gurgling quality. Unlike fine crackles, they sometimes partially clear after a productive cough because secretions in the bronchi are being moved.

Conditions associated with coarse crackles include:

• Severe pulmonary edema
• Advanced pneumonia
• Bronchiectasis
• COPD exacerbation with retained secretions — see COPD nursing

Nursing interventions for crackles:

• Position the patient with the head of bed elevated 30–45 degrees to optimize ventilation-perfusion matching and reduce basal atelectasis
• Encourage deep breathing exercises and incentive spirometry for post-operative patients
• Monitor SpO2 continuously — a new drop in oxygen saturation alongside new crackles warrants immediate provider notification. For SpO2 targets and oxygen delivery devices, see oxygen therapy nursing
• For coarse crackles from secretions: encourage coughing, offer chest physiotherapy if ordered, and be prepared to suction if the patient cannot clear their airway

Clinical severity: Fine crackles at the bases that clear with a few deep breaths are expected in a post-operative patient who has been lying flat. Persistent bilateral crackles that extend upward from the bases, accompanied by worsening dyspnea and declining SpO2, suggest fluid overload — notify the provider now.

Wheezes

Wheezes are continuous, musical, high-pitched sounds produced by air moving through narrowed or constricted small airways (bronchioles). The narrowing causes the airway walls to flutter and vibrate, generating the characteristic whistling tone. Wheezes are predominantly expiratory because the airways naturally narrow during exhalation; in severe obstruction, wheezing becomes audible on both inspiration and expiration.

The American Thoracic Society defines wheezes as continuous adventitious sounds with a dominant frequency of 400 Hz or higher.

Conditions associated with wheezes include:

• Asthma — the classic presentation; see asthma nursing for management
• COPD — especially during exacerbations
• Anaphylaxis — bronchospasm from the allergic cascade; always paired with systemic signs
• Airway foreign body — often produces a localized, unilateral wheeze
• Cardiac asthma — wheezes caused by interstitial pulmonary edema mimicking bronchospasm

Critical NCLEX trap: A patient with severe asthma who previously had wheezes and now has a silent chest (no breath sounds, no wheeze) is a medical emergency. The absence of wheezing does not signal improvement — it signals that airflow has become so restricted that no air is moving through to generate sound. This patient needs immediate escalation.

Nursing interventions for wheezes:

• Administer short-acting bronchodilators (albuterol) as ordered; reassess lung sounds after treatment
• Position upright to maximize diaphragm excursion
• Monitor peak flow if ordered and SpO2 with pulse oximetry — refer to pulse oximetry and capnography for monitoring guidance
• Avoid respiratory irritants; keep the environment calm to reduce anxiety-driven bronchospasm
• A new wheeze in a patient who was previously wheeze-free, particularly in the context of a new medication or food exposure, raises concern for anaphylaxis — assess for hives, hypotension, and throat tightening

Rhonchi

Rhonchi (singular: rhonchus) are continuous, low-pitched, rumbling sounds that originate from secretions or narrowing in the larger central airways — the trachea and bronchi. Clinically, the sound resembles loud snoring. Rhonchi are predominantly expiratory, though they can sometimes be heard on inspiration as well.

Terminology note: The American Thoracic Society and the American College of Chest Physicians have discouraged “rhonchi” as a distinct category, preferring to classify these sounds simply as low-pitched wheezes or coarse crackles depending on their characteristics. Despite this, rhonchi remain in wide clinical use and appear on the NCLEX. Know both systems. On the NCLEX: if the sound is continuous, low-pitched, and clears with coughing — it is rhonchi. If it is continuous and high-pitched — it is a wheeze.

Key distinguishing feature: Rhonchi often improve or change character after coughing. This happens because the sound is generated by secretions in the large airways, and effective coughing moves those secretions. Wheezes do not clear with coughing because they originate from airway wall narrowing, not secretions.

Conditions associated with rhonchi include:

• COPD with increased mucus production
• Chronic bronchitis
• Aspiration of secretions
• Post-operative patients with retained secretions

Nursing interventions for rhonchi:

• Encourage coughing and deep breathing; note whether sounds change after the patient coughs
• Ensure adequate hydration to thin secretions (unless contraindicated by fluid restriction)
• Suctioning via nasopharyngeal or endotracheal route if the patient cannot clear secretions
• Chest physiotherapy or postural drainage if ordered
• Reassess lung sounds after any intervention and document the change

Stridor

Stridor is a harsh, high-pitched inspiratory sound generated by turbulent airflow through a narrowed upper airway — the larynx, trachea, or subglottic space. Unlike the sounds discussed above, stridor is often loud enough to hear without a stethoscope. When you do auscultate, it is loudest over the neck rather than the chest wall.

Stridor is always an emergency until proven otherwise.

Timing and location clues:

• Inspiratory stridor → extrathoracic upper-airway obstruction (supraglottic edema, laryngospasm, croup, epiglottitis, vocal cord lesion)
• Expiratory stridor → intrathoracic obstruction (tracheomalacia, extrinsic compression of the trachea)
• Biphasic stridor (both phases) → fixed lesion, such as subglottic stenosis

Common clinical causes of stridor:

• Post-extubation laryngospasm or laryngeal edema
• Anaphylaxis with upper airway angioedema
• Croup (laryngotracheobronchitis) in pediatric patients
• Epiglottitis (bacterial, typically Haemophilus influenzae type b in unvaccinated patients, or group A Streptococcus)
• Foreign body aspiration
• Inhalation injury with supraglottic burns

For a comprehensive overview of airway interventions in emergencies, see airway management nursing.

Nursing interventions for stridor:

• Call the provider immediately and activate the rapid response team if the patient is in acute distress
• Position the patient upright (sitting forward helps maintain patent airway)
• Administer supplemental oxygen as ordered; avoid stimulating the patient unnecessarily — in epiglottitis specifically, agitation can worsen obstruction
• Prepare for potential advanced airway management: have bag-valve-mask, suction, and intubation equipment at bedside
• Administer racemic epinephrine or corticosteroids per order for post-extubation stridor or croup
• In anaphylaxis: administer epinephrine 0.3 mg IM per protocol immediately; call for advanced airway support

Pleural friction rub

A pleural friction rub is a grating, leathery, creaking sound produced when inflamed pleural surfaces rub against each other during the respiratory cycle. Unlike most lung sounds, a pleural friction rub is heard during both inspiration and expiration, and the expiratory component typically mirrors the inspiratory component. The sound is localized to the area of pleural inflammation and does not change with coughing — this helps distinguish it from rhonchi.

Patients with a pleural friction rub frequently have localized pleuritic chest pain that worsens with inspiration, coughing, and movement.

Conditions associated with pleural friction rub include:

• Pleuritis (pleurisy) — inflammation of the pleura from viral, bacterial, or inflammatory causes
• Pulmonary embolism — infarction at the lung periphery causes pleural inflammation
• Pneumonia with pleural extension
• Malignancy involving the pleura
• Autoimmune conditions (lupus, rheumatoid arthritis)

Nursing interventions for pleural friction rub:

• Assess the patient’s pain level — pleuritic pain severely limits deep breathing and increases the risk of atelectasis
• Position the patient on the affected side if comfort allows — this can splint the inflamed area and reduce pain with breathing
• Administer analgesics as ordered to facilitate adequate ventilation
• Notify the provider — the underlying cause (especially PE or pneumonia with effusion) requires diagnosis and treatment
• Monitor oxygen saturation and respiratory rate; declining oxygenation suggests significant restriction of ventilation

Auscultation technique

Correct technique ensures you hear what is actually there.

Equipment and environment:

• Use the diaphragm of the stethoscope for lung sounds (the bell amplifies low-frequency heart sounds)
• Warm the diaphragm before placing it on the patient’s skin — cold metal causes muscle tension
• Always auscultate on bare skin, never through a gown or clothing, which creates artifact
• Conduct the assessment in as quiet a room as possible

Patient positioning:

• Sitting upright is the preferred position — it opens the lung bases and allows you to access both anterior and posterior fields
• For patients on bed rest: raise the head of bed to 45–90 degrees and use a side-to-side comparison pattern
• For patients who tire easily, begin at the lung bases — these are the most clinically vulnerable zones and you want to hear them while the patient can still cooperate

Systematic sequence:

1. Begin at the lung apices anteriorly
2. Move downward in a side-to-side zigzag pattern, comparing left and right at each level
3. Auscultate the lateral fields (mid-axillary line)
4. Move to the posterior chest from the apices downward
5. Allow at least one full respiratory cycle per auscultation site
6. Ask the patient to breathe through an open mouth with slow, moderately deep breaths — mouth breathing eliminates upper airway sounds that can be confused with adventitious sounds

Documentation: Document the type of sound, the location (e.g., bilateral bases, right lower lobe), the phase of respiration (inspiratory, expiratory, or both), and whether the sound changes with interventions. Example: “Bilateral fine crackles at bilateral bases, more prominent on the right, present throughout inspiration, did not clear with three deep breaths. SpO2 92% on 2L NC.” This level of detail communicates clinical severity clearly. Refer to head-to-toe assessment for how respiratory assessment fits into your full assessment framework.

Clinical significance and when to escalate

Not every adventitious sound is an emergency. Knowing which sounds require immediate action separates safe practice from dangerous delays.

Escalate immediately:

• Stridor — any cause, any setting. This is an upper airway emergency.
• Silent chest in a patient with known asthma — absent wheezes with severe dyspnea signals critical obstruction
• New bilateral crackles rising from the bases in a patient with worsening dyspnea and declining SpO2 — suggests flash pulmonary edema
• New unilateral breath sound changes post-intubation — suggests right mainstem intubation or pneumothorax
• Wheeze with systemic signs (hypotension, urticaria, throat tightness) — anaphylaxis

Monitor and notify within the hour:

• New wheezes in a patient not known to have asthma or COPD — establish a cause
• Rhonchi that do not improve after coughing and deep breathing — suggests thick secretions or a more significant obstruction
• Pleural friction rub — the underlying cause needs investigation

Expected and manageable:

• Fine bibasilar crackles in a post-operative patient that clear with incentive spirometry and deep breathing exercises — atelectasis responding to treatment
• Mild expiratory wheezes in a known COPD patient that improve after scheduled bronchodilator

NCLEX tips

• Crackles are discontinuous (intermittent); wheezes and rhonchi are continuous
• Fine crackles are high-pitched, late-inspiratory, and do not clear with coughing
• Coarse crackles are low-pitched, early-inspiratory, and may partially clear with coughing
• Rhonchi are low-pitched, continuous, expiratory, and often improve after coughing — this distinguishes them from wheezes
• Wheezes are high-pitched, continuous, predominantly expiratory, and do not clear with coughing
• Stridor is inspiratory, high-pitched, loudest over the neck, and always a priority finding
• A “silent chest” in an asthma patient is more dangerous than loud wheezing — select the option that reflects immediate escalation
• Pleural friction rub is biphasic (heard on both inspiration and expiration) and does not change with coughing
• The ATS discourages the term “rales” — use “crackles.” The NCLEX uses both; know them as synonyms
• Post-extubation stridor requires immediate assessment for laryngeal edema; racemic epinephrine and corticosteroids are common interventions
• In a patient with heart failure, crackles that extend from the bases upward toward the apices indicate worsening fluid overload — a higher-priority finding than crackles at the bases alone
• Fine crackles in a patient over 60 with progressive dyspnea and no other explanation — think interstitial lung disease / IPF
• During a nursing head-to-toe assessment, lung auscultation follows inspection and palpation of the thorax — sequence matters on NCLEX select-all-that-apply questions
• Always reassess lung sounds after any respiratory intervention (nebulizer treatment, suctioning, diuresis) and document the change

NCLEX practice scenarios

Question 1 A nurse auscultates a patient admitted with exacerbation of heart failure. She hears soft, high-pitched, popping sounds in both lower lung fields during inspiration that do not clear after three deep breaths. The patient’s SpO2 is 90% on 2L nasal cannula. Which action is the nurse’s priority?

A. Encourage the patient to cough and deep breathe
B. Notify the provider immediately
C. Increase oxygen to 4L nasal cannula and reassess in 30 minutes
D. Position the patient on the right side

Answer: B
Rationale: Bilateral fine crackles with SpO2 of 90% in a heart failure patient signal significant pulmonary congestion. Provider notification is the priority — diuresis or medication adjustment is needed. Coughing and deep breathing address atelectasis, not fluid overload. Independently increasing oxygen without notification is outside the nurse’s scope in this context. The left lateral position is not a standard intervention here.

Question 2 A nurse caring for a patient 4 hours post-extubation hears a harsh, high-pitched sound on inspiration that is audible without the stethoscope. The patient is sitting upright and appears anxious. What is the nurse’s first action?

A. Administer a scheduled nebulizer treatment
B. Encourage slow, deep breaths and reassess
C. Call the provider and prepare for potential airway intervention
D. Apply a non-rebreather mask at 15L/min

Answer: C
Rationale: Post-extubation stridor indicates laryngeal edema or laryngospasm — a potential airway emergency. The provider must be notified immediately and airway management equipment made ready. A nebulizer addresses bronchospasm, not upper airway obstruction. Encouraging deep breaths delays necessary intervention. Applying a non-rebreather is a supportive step but not the first priority — provider notification and preparation for definitive airway management come first.

Question 3 A nurse auscultates a patient’s lungs and hears a continuous, low-pitched, snoring sound bilaterally during expiration. After the patient coughs productively, the sound diminishes significantly. What term best describes this finding?

A. Fine crackles
B. Stridor
C. Rhonchi
D. Pleural friction rub

Answer: C
Rationale: Continuous, low-pitched, expiratory sounds that improve after coughing are the defining characteristics of rhonchi. They originate from secretions and narrowing in the large airways. Fine crackles are discontinuous. Stridor is inspiratory and heard over the neck. Pleural friction rub is biphasic and does not change with coughing.

Question 4 A nurse is caring for a child with croup. The child’s mother reports the barking cough has worsened over the past hour and the child now appears to be working hard to breathe. The nurse auscultates and hears a harsh sound on inspiration. Which finding would indicate the child’s condition is worsening and requires immediate escalation?

A. Barking cough with rhinorrhea
B. Stridor at rest with intercostal retractions
C. Low-grade fever of 38°C
D. Crackles at the right lung base

Answer: B
Rationale: Stridor at rest (as opposed to only with crying or agitation) combined with intercostal retractions indicates significant upper airway obstruction requiring immediate intervention. Barking cough with rhinorrhea is typical of croup. Low-grade fever is expected. Crackles at the base suggest lower airway involvement — a separate concern, but stridor at rest with retractions is the immediate priority.

Question 5 A patient with a history of asthma is brought to the emergency department by her family who say she has been having an attack for 40 minutes and her inhaler is no longer helping. On assessment, the nurse notes the patient is in a tripod position, has a respiratory rate of 36 breaths/min, and her lung fields are silent bilaterally. What does this finding indicate?

A. Resolution of bronchospasm — the treatment is working
B. Critical airway obstruction requiring immediate escalation
C. The patient is breathing too shallowly to generate sounds
D. Misplacement of the stethoscope

Answer: B
Rationale: A silent chest in an asthma patient with ongoing distress is a life-threatening finding. It indicates severe bronchospasm with such limited airflow that no sound is generated — the opposite of improvement. This patient requires immediate bronchodilator therapy (albuterol, ipratropium), systemic corticosteroids, possible magnesium sulfate, and preparation for mechanical ventilation. Answer A is a dangerous misinterpretation that the NCLEX tests explicitly.

Question 6 The nurse auscultates lung sounds and hears a grating, creaking sound during both inspiration and expiration, localized to the left lateral chest wall. The patient reports sharp chest pain that worsens when she breathes in. The sound does not change after coughing. What does the nurse suspect?

A. Coarse crackles from retained secretions
B. Rhonchi from mucus in large airways
C. Pleural friction rub from inflamed pleural surfaces
D. Stridor from upper airway edema

Answer: C
Rationale: Biphasic grating or creaking sounds that do not change with coughing, localized to one area, combined with pleuritic chest pain, describe a pleural friction rub. The localized nature and cough-independence distinguish it from rhonchi and crackles. Stridor would be heard over the neck and on inspiration only.

Related skills

Adventitious lung sounds are one component of a broader respiratory and physical assessment skill set. To deepen your clinical foundation, review these related pages:

• Head-to-toe assessment — where lung auscultation sits within the full systematic assessment
• Oxygen therapy nursing — delivery devices, SpO2 targets, and when to escalate oxygen requirements
• Pulse oximetry and capnography — the monitoring tools you use alongside auscultation to track respiratory status
• Airway management nursing — next steps when lung sounds signal an airway emergency
• Pneumonia nursing — crackles as a key assessment finding in pneumonia
• Asthma nursing — wheeze pattern, bronchodilator response, and the silent chest emergency
• COPD nursing — rhonchi and wheezes in chronic obstructive disease