#22 – Approach to Dyspnea in the ED



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Epidemiology

Dyspnea is one of the more common complaints that will bring a patient to the ED for evaluation.  The most recent data from the CDC shows more than 3.7 million visits to the ED in the United States for shortness of breath alone and more than 11 million for dyspnea-related complaints (cough, chest pain, etc.).

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Pathophysiology

There are 3 global processes that have to function in series to prevent a patient from becoming short of breath:

  • Ventilation
    • Airflow through the tracheobronchial tree to the terminal alveoli
    • Ventilation without perfusion = Dead space
      • Anatomic = trachea, main bronchi
      • Physiologic = terminal alveoli
  • Perfusion
    • Blood flow through the pulmonary arteries to the terminal capillaries
    • Perfusion without ventilation = Intrapulmonary shunt
      • Anatomic = right-to-left shunt
      • Physiologic = terminal alveoli
  • Gas Exchange
    • Capillary-alveoli interface to exchange oxygen and carbon dioxide
      • Determined by arterial-alveoli gradient

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5 Main Causes of Hypoxemia

  • V/Q Mismatch (most common)
    • PNA, PTE, pulmonary edema, asthma, COPD
  • Hypoventilation
    • Drug overdose, neuromuscular disease (GBS, ALS, MG)
  • Right-to-Left Shunt
    • Intracardiac
      • PFO, ASD, VSD
    • Vascular
      • PTE, AVM
    • Alveolar
      • PNA, atelectasis, pulmonary edema, ARDS
  • Low Inspired Oxygen
    • Altitude, fire,
  • Diffusion Abnormality
    • COPD, interstitial lung disease

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Bedside Evaluation

Vitals

  • Blood Pressure
    • Often hypertensive due to stress
    • Can also be the precipitating factor
  • Heart Rate
    • Often tachycardic due to stress and system trying to increase cardiac output for oxygen demand
    • If bradycardic à think overdose
  • Respiratory Rate
    • Will be tachypnic
      • > 40 bpm is ominous and respiratory failure could be imminent
    • if bradypnic à think overdose
  • Temperature
    • If febrile, then infectious causes go up on differential
  • Pulse oximetry
    • Common practice is to give all dyspneic patients oxygen
      • Lots of research on oxygen in ACS

History

  • Onset
  • Severity
  • Events leading up to this episode
    • Triggers, compliance with medications
  • Allergies
  • Past History
    • Medical problems, previous episodes
  • Chest pain
  • Trauma
  • Fever
  • Hemoptysis
  • Cough
  • Tobacco history
  • Medications

 

Physical Exam

Rapid examination should be performed (often while getting the history) to evaluate for impending respiratory collapse:

  • Altered mental status
    • Lethargy to combative
  • Fatigue of breathing
  • Audible stridor
  • Cyanosis
  • Tripod position
  • Retractions or accessory muscle use
  • Fragmented speech
  • Inability to lie supine
  • Diaphoresis

Any of the above findings should raise your threshold to intubate.

 

Once these have been evaluated and ruled-out, you can begin a focused physical exam to address the causes of acute dyspnea:

  • Pulmonary
    • Breath sounds
      • Wheezing, diminished, equal, crackles, rales
  • Cardiovascular
    • Rhythm
      • Tachycardia, irregular
    • Murmurs
    • S3/S4
    • Distant/muffled heart sounds
    • Edema/JVD
  • Skin
    • Diaphoresis
    • Capillary refill
    • Urticaria

screen-shot-2016-11-17-at-10-47-37-am


Work-Up


Differential Diagnosis

  • Upper Airway
    • Angioedema
    • Foreign body
    • Anaphylaxis
    • Infections
    • Trauma
  • Pulmonary
    • PTE
    • COPD
    • Asthma
    • Edema
    • PTX
    • Pneumonia
    • Trauma
    • Hemorrhage
    • Effusion
  • Cardiac
    • Acute decompensated heart failure
    • ACS
    • Cardiomyopathy
    • Dysrhythmias
    • Valvulopathies
    • Effusion/tamponade
  • Neurologic
    • Neuromuscular
      • GBS, MG, ALS
  • Metabolic/Toxic
    • Overdose
    • Carbon monoxide poisoning
    • Acute chest syndrome in sickle cell disease
  • Miscellaneous
    • Anxiety
    • Ascites

Management

Three main primary goals for the emergent management of acute dyspnea:

  • Optimize arterial oxygenation
    • Provide supplemental oxygen
    • Continuous cardiac and pulse oximetry monitoring
  • Determine need for emergent airway management
    • Bring airway supplies to the bedside
      • Non-invasive ventilation is an option
      • Include difficult airway adjuncts as well
  • Determine most likely cause and initiate treatment
    • Start work-up (as outlined above)
    • Don’t let a definitive diagnosis preclude starting treatment

References

 

  1. National Hospital Ambulatory Medical Care Survey: 2011 Emergency Department Summary. http://www.cdc.gov/nchs/data/ahcd/nhamcs_emergency/2011_ed_web_tables.pdf.  Accessed on November 15th,2016.
  2. Petersson J, Glenny RW. Gas exchange and ventilation-perfusion relationships in the lung. The European Respiratory Journal. 2014;44(4):1023-41. [pubmed]
  3. Simon PM, Schwartzstein RM, Weiss JW, Fencl V, Teghtsoonian M, Weinberger SE. Distinguishable types of dyspnea in patients with shortness of breath. The American Review of Respiratory Disease. 1990;142(5):1009-14. [pubmed]
  4. Schabowski S, Lin C. Dyspnea. In: Sherman SC, Weber JM, Schindlbeck MA, Rahul G. P. eds. Clinical Emergency Medicine, 1e. New York, NY: McGraw-Hill; 2014. http://accessemergencymedicine.mhmedical.com/content.aspx?bookid=991&Sectionid=55139128 . Accessed November 16, 2016.
  5. Fertel BS. Respiratory Distress. In: Cydulka RK, Cline DM, Ma O, Fitch MT, Joing S, Wang VJ. eds. Tintinalli’s Emergency Medicine Manual, 8e. New York, NY: McGraw-Hill; 2016. http://accessemergencymedicine.mhmedical.com/content.aspx?bookid=1759&Sectionid=128948449 . Accessed November 16, 2016.
  6. Schneider HG, Lam L, Lokuge A. B-type natriuretic peptide testing, clinical outcomes, and health services use in emergency department patients with dyspnea: a randomized trial. Annals of Internal Medicine. 2099;150(6):365-71. [pubmed]
  7. Ahmed A, Graber MA. Evaluation of the adult with dyspnea in the emergency department.  In: UpToDate, edited by Hockberger RS, Grayzel J.  UpToDate, Waltham, MA. 2016.  https://www.uptodate.com/contents/evaluation-of-the-adult-with-dyspnea-in-the-emergency-department?source=see_link#H29. Accessed November 16, 2016.

PAINE PANCE Pearl – Emergency Medicine



57-year-old male, with controlled hypertension, presents to emergency department with a 2-hour history of a central, dull, chest pain that does not radiate.  He rates it as a 4/10 in severity and denies any aggravating or alleviating factors.  He reports some mild nausea and what he reports as “reflux” during this event as well.  He denies shortness of breath, vomiting, arm radiation, back radiation, abdominal pain, dizziness, or syncope.  His father has HTN, HLP, and had a non-fatal AMI at 62-years-old.  He is a never smoker.  His BMI is 27.3.

 

Vital signs show BP-122/82, HR-93, RR-16, O2-100% on room air, and temp-98.0.

 

Physical exam reveals:

HEENT – NC/AT

Skin – no diaphoresis

Cardiovascular – RRR without M/G/R

Pulmonary – CTA without adventitial breath sounds

Abdomen – S/ND, mild epigastric tenderness to deep palpation

Peripheral Vascular – 2+ pulses throughout

Neuro – A&Ox3, 5/5 strength throughout

 

EKG is below:

normal_ecg

 

Laboratory Screening:

High-sensitivity troponin (hs-cTnI) – 0.02 ng/dL

CK-MB – 39 U/L

Total CK –  264 U/L

Myoglobin – 22 ng/mL



WHAT WOULD YOU DO NEXT???



Answer:

Discharge home with cardiovascular provocative testing as outpatient.

 

Why?  Low risk HEART score.  What is the HEART score?  Glad you asked.

 

The HEART score was first published in 2008 to evaluate occurrence of Major Adverse Cardiac Event (MACE) at 6 weeks.  MACE defined in the study was any occurrence of AMI, PCI, CABG, or death.  The 5 variables they used are:

 

the-heart-score

R.E.B.E.L EM – A New ED Chest Pain Risk Stratification Score

 

The HEART score performed better than TIMI and GRACE predicting MACE in acute chest pain patients presenting to the ED.

 

For our patient, he has a HEART score of 3 (age + history + risk factors).  We could have a discussion with him regarding the risk of him having a MACE in the next 6 weeks and the risks/benefits of admission and testing now.  Below is a nice patient sheet that the University of Maryland (FEAR THE TURTLE) has developed to help with shared decision making in the ED.

 

screen-shot-2016-11-09-at-5-12-26-pm

University of Maryland. http://tinyurl.com/nc2k65n

 


References

  1. Six AJ, Backus BE, Kelder JC. Chest pain in the emergency room: value of the HEART score. Netherlands Heart Journal. 2008;16(6):191-6. [pubmed]
  2. Backus BE, Six AJ, Kelder JC. A prospective validation of the HEART score for chest pain patients at the emergency department. International Journal of Cardiology. 2013;168(3):2153-8. [pubmed]
  3. R.E.B.E.L. EM – A New ED Chest Pain Risk Stratification Score.  January 10, 2014. http://rebelem.com/heart-score-new-ed-chest-pain-risk-stratification-score/#ITEM-588-2

PAINE PANCE Pearl – Emergency Medicine



57-year-old male, with controlled hypertension, presents to emergency department with a 2-hour history of a central, dull, chest pain that does not radiate.  He rates it as a 4/10 in severity and denies any aggravating or alleviating factors.  He reports some mild nausea and what he reports as “reflux” during this event as well.  He denies shortness of breath, vomiting, arm radiation, back radiation, abdominal pain, dizziness, or syncope.  His father has HTN, HLP, and had a non-fatal AMI at 62-years-old.  He is a never smoker.  His BMI is 27.3.

 

Vital signs show BP-122/82, HR-93, RR-16, O2-100% on room air, and temp-98.0.

 

Physical exam reveals:

HEENT – NC/AT

Skin – no diaphoresis

Cardiovascular – RRR without M/G/R

Pulmonary – CTA without adventitial breath sounds

Abdomen – S/ND, mild epigastric tenderness to deep palpation

Peripheral Vascular – 2+ pulses throughout

Neuro – A&Ox3, 5/5 strength throughout

 

EKG is below:

normal_ecg

 

Laboratory Screening:

High-sensitivity troponin (hs-cTnI) – 0.02 ng/dL

CK-MB – 39 U/L

Total CK –  264 U/L

Myoglobin – 22 ng/mL