When you ask newer EMTs to take a set of vitals, inevitably they will take a patient’s pulse, measure their respiratory rate, measure their blood pressure, and perhaps even put the pulse oximetry probe on a finger. What isn’t as often an ingrained response is listening to a patient’s lung sounds. So many acute and chronic presenting problems can be detected with an appropriately timed and placed listening of the lungs—hence the old adage “Everyone gets an auscultation.” This article will review some common lung sounds and the conditions they might represent.
Where to Listen and for What
Contrary to what you might see in the field, you don’t need an expensive stethoscope to listen to lung sounds. While certain cardiology-type models might enhance clarity when it comes to acoustics, your standard jump-bag stethoscope will get the job done.
Using the larger side of the stethoscope diaphragm, listen by auscultating both the anterior and posterior chest. As you move the bell, auscultate from top to bottom in a stepwise pattern, comparing sides with each placement of the stethoscope. Take your time! Try to listen to at least one complete respiratory cycle at each location and have the patient breathe normally. If you can’t hear that way, ask the patient to take a deep breath.
In addition to specific sounds, try to note the length of the expiration and inspiration as well as symmetry between sides of the chest. Listen for the timing during the respiratory cycle in which you hear an adventitious lung sound, as this may help point to underlying pathology. For example, inspiratory stridor may easily be mistaken for expiratory wheezing by an untrained ear. Inspiratory stridor may point to upper-airway obstruction, asthma, or anaphylaxis, whereas expiratory wheezing typically indicates lower-airway obstruction.
Clear lung sounds:
Air flow is not restricted;
Both sides of the chest are symmetric in rise and fall;
No whistles, gurgles, fluid, or abnormal sounds are detected.
Diminished lung sounds:
Breath sounds are heard but with less intensity than normal, clear breath sounds;
Causes include shallow breathing, airway obstruction, hyperinflation, pneumothorax, pleural effusion, thickening due to fibrosis, and obesity.
Most commonly heard during the expiratory phase of the respiratory cycle;
Musical in quality, high-pitched and continuous;
Indicative of lower-airway obstruction secondary to asthma, chronic obstructive pulmonary disease, anaphylaxis, or acute bronchitis.
Low-pitched, continuous rumbles secondary to excess secretions in the larger airways;
Most common during expiration;
Often due to acute bronchitis or pneumonia.
Discontinuous sound of air moving past fluid, typically heard during late inspiration;
Sound has been likened to rubbing hair between your fingers;
Most commonly heard in heart failure and pneumonia.
Most commonly heard during the inspiratory phase of the respiratory cycle;
Indicative of upper airway obstruction due to foreign body, croup, epiglottitis, or anaphylaxis.
Absent lung sounds:
Breath sounds are not heard;
Causes may include respiratory arrest, pneumothorax.
Positioning—It is important to formulate a list of differential diagnoses based upon physical examination findings to determine an appropriate prehospital management plan for the respiratory distress patient. In all cases where a patient can maintain their own airway, transport them seated upright. The posterior lung fields are responsible for more than half the pulmonary circulation, so make every effort to allow complete expansion of the thorax during ventilatory efforts.
Further assessment—Review the patient’s symptoms and conduct the physical examination prior to administering any treatment. Is the patient experiencing respiratory complaints such as shortness of breath, cough, production of sputum, or cyanosis? Further evaluate symptoms through objective physical examination, including vital signs and a focused auscultation of the lungs. Note the patient’s unassisted rate, effort, depth, and quality of breathing upon arrival.
Oxygen therapy—If indicated, initiate supplemental oxygen therapy using an appropriate delivery device. Conscious patients experiencing shortness of breath or hypoxia (oxygen saturation of less than 94%) should receive oxygen via nasal cannula at a rate of 2–6 lpm or nonrebreather mask at 6–15 lpm. Titrate supplemental oxygen therapy to a saturation of 94%–99% or until symptoms improve.
Patients experiencing severe respiratory distress with respirations less than 4 or greater than 28 breaths per minute should undergo assisted ventilation with a bag-valve mask (BVM), with one breath every 4–6 seconds and high-flow oxygen at 15 lpm. Patients unable to maintain their own airway due to decreased level of consciousness (Glasgow Coma Scale score less than 8) should have an oropharyngeal or nasopharyngeal airway placed as tolerated, with suctioning of the airway as needed and assisted ventilations via BVM. ALS providers may consider advanced airway adjuncts such as endotracheal intubation.
Continuous positive airway pressure (CPAP) may be considered in patients over 18 years of age with an increased work of breathing, respiratory rate greater than 24 bpm, and oxygen saturation of less than 94%. Limit positive end-expiratory pressure (PEEP) to no more than 10 cm H2O in the prehospital setting. Presently most BVMs are equipped with a PEEP valve. The most common prehospital indication for CPAP is an acute exacerbation of congestive heart failure, which may be picked up on physical examination through the presence of jugular venous distention, rales on auscultation, or peripheral pitting edema. Regularly review your local indications and contraindications for the use of CPAP, as well as how to properly use the device your agency carries.
Base management with medications upon your local, regional, and state protocols as well as the patient’s known medical history and presenting symptoms and signs. For patients presenting with wheezing and a history of COPD or asthma, consider giving albuterol via metered-dose inhaler or nebulizer. Based on the severity of the patient’s breathing, albuterol can be given via nebulizer with CPAP.
For patients presenting with wheezes secondary to anaphylaxis, administration of epinephrine via auto-injector or syringe is warranted, within your local protocols.
If the patient has absent breath sounds due to a sucking chest wound from trauma, consider placing a chest seal or other occlusive dressing until the patient can have a chest decompression in the field or a tube inserted at a hospital. If the patient has absent breath sounds due to apnea secondary to an opiate overdose, consider administering naloxone. Lastly, if absent breath sounds are due to a foreign body obstruction or choking, the Heimlich maneuver for a conscious patient and CPR for an unconscious patient is warranted.
For all medications it is important to reassess the patient after treatment to determine their response. Repeat vital signs at appropriate intervals and reauscultate in all lung fields. Adjust treatments according to the patient’s response within medical direction and protocols.
A complete assessment of a patient includes pulse rate, respirations, blood pressure, skin, stroke assessment, pupils, and orientation as part of the vital signs. Don’t forget a detailed lung sound assessment at the start and throughout the patient encounter. Everyone gets an auscultation!
Barry Bachenheimer, EdD, EMT/FF, is a career educator and college professor. With a fire and EMS career of more than 34 years and counting, he is a frequent contributor to EMS World. He is the co-training officer for the South Orange (N.J.) Rescue Squad.
Kristina Dauernheim, MS, PA-C, EMT, is a surgical physician assistant with more than eight years of EMS experience. She is a co-training officer for the South Orange (N.J.) Rescue Squad.