Definition

Dyspnea is the sensation of shortness of breath. It is often described as a sensation of running out of air or not being able to breathe deep enough or breathing too fast. Dyspnea results from multiple interactions between the nervous system, upper airway, lungs, and chest wall. It is a common finding in many different conditions.

Differential Diagnosis

Acute Onset Dyspnea

Evaluation

An initial history and physical examination can yield important information as to the etiology of the dyspnea.  Pay close attention to the vital signs, the acuity of onset and any new events (i.e. medications, IV fluids, blood product transfusions) that occurred recently. Guide your further evaluation by this initial information.

• Cardiac
  • Obtain 12-lead ECG to rule out ischemia or arrhythmia. 
  • Pay close attention to volume status on exam.
  • Bedside ultrasound for IVC assessment can be helpful. IVC diameter (measured 1 cm distal to the hepatic vein) >2 cm and with <50% respiratory variation suggests CHF with elevated filling pressures (https://www.youtube.com/watch?v=qHWLFfXtGn8). 
  • In the setting of tamponade, hypotension, tachycardia and a narrow pulse pressure are usually present. If suspicion is high, measure a pulsus paradoxus (easy with an arterial line) though an echocardiogram will likely be needed to confirm the diagnosis.
• Pulmonary:
  • Examine for rales, wheezing, stridor and symmetry of breath sounds.
  • Obtain CXR, arterial blood gas, assess for potential need for intubation (i.e.: hypercapnia, altered mental status with airway compromise). 
  • With appropriate training, bedside lung ultrasound allows for improved ability to differentiate causes of dyspnea compared to physical exam and CXR (https://www.youtube.com/watch?v=RBgGA_rqVvE).
  • Pulmonary embolism should always be considered; a contrast CT of the chest for PE can be obtained after stabilization if clinically indicated. See Pulmonary: Pulmonary Embolism section.

Management

• Oxygen:
  • Initial intervention for any patient who is dyspneic.
  • Goal PaO2>60 and SpO2>92% in most patients.
  • Chronic CO2 retainers may need only an oxygen saturation of 90-92% due to need for hypoxic respiratory drive.
  • Call respiratory therapy early to aid in management.
• Suction upper airway if concerned for aspiration.
• Place the patient in the Fowler’s or Reverse Trendelenburg positions. 
• β-agonists: If concern for bronchospasm (wheezing on exam, history of asthma/COPD), consider albuterol and/or ipratropium via nebulizer or inhaler.
• Diuretics:
  • If there is concern for volume overload and pulmonary edema, consider IV furosemide or bumetanide.
  • Take caution with over-diuresis in patients with preload dependent conditions such as RV failure/infarct, pulmonary hypertension, tamponade, hypertrophic cardiomyopathy, and aortic stenosis.
• Intubation and NIPPV:
  • NIPPV can be useful in cardiogenic pulmonary edema and acute respiratory failure in COPD exacerbations.
  • Indications for intubation include: severe hypercapnia, refractory hypoxia, airway obstruction, and failure to protect the airway (e.g. profound altered mental status).
  • See Critical Care: Mechanical Ventilation for more information.

Key Points

• CXR, ECG and ABG for all dyspneic patients.
• Always give oxygen initially and call respiratory therapy for help.
• Don’t be afraid to intubate the patient if needed as long as it is within goals of care.
• Check code status before intubation if possible.
• Once the patient is stabilized, initiate definitive therapy for the specific etiology of the patient’s dyspnea.
• Remember to consider pulmonary embolism as the etiology.
• Check for recent IVF administration especially in surgical patients.

Zoorob, R and Campbell, J. “Acute dyspnea in the Office.” AmFam Physician 2003; 68:1803-10

Boyars, M; Karnath, B; Mercado, A. “Acute Dyspnea: A Sign of Underlying Disease.” Hospital Physician 2004, 23-27

Soni NJ, Arntfield R, Kory P. Point-of-Care Ultrasound. 2nd Edition. Elsevier 2019.