Where to Listen for Lung Sounds: The Complete Guide to Respiratory Auscultation Examination
The Respiratory Assessment and Examination
A respiratory assessment is an integral part of any head-to-toe physical exam. A proper respiratory examination and assessment involves both skill and practice.
The following outlines the steps you should use in performing a respiratory assessment as well as how to identify potential abnormal signs and symptoms suggestive of pathology. But before we start – have you got a stethoscope? If not, check out our guides on how to choose the best stethoscope for every field of healthcare.
STEP 1: Start with the General Inspection:
You can begin making deductions about what you’re likely to find in the lung auscultation by their age and general appearance:
Young patients – think of Asthma and Cystic Fibrosis (CF)
Older Patients – think of COPD, interstitial lung disease, infection, or malignancy.
Is the patient short of breath? Are they exhibiting other clues such as pursed lip breathing, use of accessory respiratory muscles, or nasal flaring?
Is the patient able to speak full and uninterrupted sentences with one breath? If not, this is already a sign of a moderate or severe respiratory attack.
Check the respiratory rate. Raised respiratory rate is an early sign of problems and should be taken accurately and seriously. Normal adult range is 12-20 breaths per minute.
Important Signs in a Respiratory Examination:
- Chest Wall: abnormalites and asymmetries, such as paradoxical movement or barrel chest. Look for defects of sternum, ribs, or muscles.
- Scars: check below arms and near armpits too. These give clues to previous surgeries and conditions such as Pneumonectomy (commonly for cancer) or Thoracoplasty (previously used to treat tuberculosis).
- Cyanosis: discoloration of lips and face only appears when oxygen saturation drops below 85%, so this is a very late and severe sign
- Cachexia: muscle wasting should ring alarm bells for malignancy, COPD, etc.
- Dry cough in conditions such as Asthma or interstitial lung disease
- Productive cough in conditions such as COPD, bronchiectasis, or Cystic Fibrosis
- Added sounds: Inspiratory stridor always suggests upper airway obstruction, and expiratory wheeze (more on wheeze auscultation later) is characteristic of asthma, COPD, and bronchiectasis.
- Hand signs:
- Clubbing – seen in CF, lung cancer, interstitial lung disease, bronchiectasis
- Tar staining = smoker -> likely COPD/lung cancer
- Rheumatological signs – can be associated with pleural effusions and pulmonary fibrosis
- Fine tremor – can suggest beta 2 agonist use in asthma or COPD
- Flapping tremor – is a sign of CO2 retention seen in Type 2 Respiratory failure
- Facial signs:
- Conjunctival pallor suggestive of anaemia
- Ptosis and miosis (constricted pupil) associated with Horner’s syndrome
STEP 2: Palpation
Start above the collar bone and palpate from side to side moving towards the costal angle alongside the mid-axillary line.
Examine the patient’s thorax and note whether there are symmetry and configuration. Inspect the posterior thorax and scrutinize presence of any bone deformity. Some abnormal spinal curvatures may result to breathing difficulties.
- Tracheal position: with the patient’s neck muscles relaxed (head rested) use your fingers to gently feel for the trachea and assess for equal space on either side looking for deviation.
- Pneumothorax and pleural effusions push the trachea away
- Lobar collapse and pneumonectomy pulls the trachea towards
- Apex beat: is it in its normal position at the 5th intercostal space, mid-clavicular line? Ventricular heave is associated with cor-pulmonale secondary to chronic hypoxic lung diseases.
- Chest expansion: this is done wrong 99% of the time. Make sure you learn to be the 1% that do it correctly, or it’s a worthless exercise:
Dig your finger tips firmly into the patient’s chest (without causing too much pain) on either side, with your thumbs just touching during an exhale. Without resting your palms on the patient’s chest, ask them to take a deep breath in. Your thumbs should move apart equally, at least 2 cm.
- Lymph Nodes: Palpate in the supraclavicular region, over anterior and posterior cervical chains, and axillary region for lymphadenopathy suggestive of lung cancer, sarcoidosis, or tuberculosis.
STEP 3: Auscultation (Where to Listen to Lung Sounds)
Ask the patient to breathe deeply through their mouth.
Listen from the front and back: Move from side to side, top to bottom, to compare lung sounds at each level. Auscultating from the back will often result in clearer lung sounds.
When the stethoscope is placed in the right position, it will avoid unwanted noise from other body processes such as gastrointestinal activity. If you place the stethoscope directly on a bone, you will not hear anything, so avoid listening over the scapula.
Ask the patient to cross their arms on their chest and lean forward. This pulls the scapulae apart, exposing more lung are for auscultation.
Listen carefully for the breathing patterns and sound characteristics of your patient’s respiration, paying close attention to the:
- pitch, and
- timing of the breath sounds in the respiratory cycle.
Assess sound quality (vesicular vs. bronchial), assess volume (quiet vs increased resonance), and listen for added sounds (polyphonic wheeze and crackles).
Common Respiratory Patterns on Auscultation:
- Vesicular – normal soft breath sounds throughout the lung fields.
- Bronchial – harsh breath sounds, suggestive of consolidation or fibrosis. Bronchial sounds are also normally heard over large airways. These are hollow and high-pitched, with a longer expiratory phase.
- Crackles or Rales – can be coarse, fine, or dry. These are created when inhaled air opens closed air spaces. Usually suggestive of infection, Bronchiectasis, Pleural effusion, or Pulmonary Fibrosis.
- Quiet – or absent breath sounds. Where air or fluid has replaced lung tissue.
- Wheeze – classical Asthmatic wheeze is polyphonic in nature.
To assess vocal resonance:
- Have the patient repeat “99” while listening over the chest with the stethoscope
- Increased volume in an area is suggestive of increased tissue density in the case of consolidation, collapse, or tumour.
- Decreased volume in an area of suggestive of effusion or pneumothorax.
STEP 4: Percussion
Press your non dominant hand firmly on the chest wall, nesting your middle finger between ribs. Strike the middle phalanx of your non-dominant hand firmly yet briskly with your other hand to percuss. Make sure you lift the striking finger quickly to not muffle the percussion tone.
Percuss in the same areas as you auscultate, and compare side to side. (See image above.)
Understanding what Percussion sounds Mean:
- Resonant: normal
- Dull: increased tissue density, suggestive of consolidation, fluid, collapse, or tumour
- ‘Stony’ Dull: pleural effusion
- Hyper-resonant: decreased tissue density, suggestive of unnatural air or spaces, eg. pneumothorax
It is important to corroborate your percussion findings with your auscultation findings.
For instance, did you find percussion dullness over the same area as increased vocal resonance in auscultation?
STEP 5: Further Assessment and Investigations
Based on your examination findings, you will likely want to perform further tests if indicated:
- Check oxygen saturation
- Perform a chest X-ray
- Take an arterial blood gas
- Perform a peak flow assessment
The Anatomy of the Thorax and Respiratory System
You must understand the basic anatomy of the airways and thorax to interpret your auscultation and examination findings. In particular, you should learn the borders and surface anatomy of the lung lobes. Examiners in particular like to quiz students which lung lobe contains the likely pathology found during the respiratory assessment.
Here are some important fundamentals:
- The lobes of both lungs; two on the left and three on the right.
- Important landmarks of the Lung borders: Anteriorly the apex begins 1 inch above the medial 1/3rd of the clavicle, inferiorly till the 6th rib at the mid-clavicular line and 10th thoracic vertebra midline posteriorly.
- The oblique fissure (bilaterally) runs from 3rd thoracic spine to the 6th costal cartilage.
- The Horizontal fissure (right side) runs from the 4th costal cartilage till it meets the oblique fissure.
If you place the stethoscope below the 6th intercostal space anteriorly, you will no longer hear respiratory sounds, but instead intestinal sounds.
The ideal place for auscultation is the posterior chest since there are fewer muscles and bones to disperse sound.
Lung Sounds & Auscultation Video
One of the most important auscultation skills for medical practitioners to master is Respiratory auscultation. The first step is to learn where to listen to lung sounds and understanding their significance. We hope this above guide was helpful in learning the respiratory examination and lung auscultation.
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