#22 – Approach to Dyspnea in the ED



LISTEN TO THE PODCAST HERE


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.

Update to Pneumonia Podcast

 

It figures.

 

As with any educational or academic en devour, as soon as you finish a paper/poster/presentation, a new publication comes out that would have been awesome to include.  I finished and published the Pneumonia podcast on July 12th and on July 14th, the IDSA/ATS released their updated guidelines on managing healthcare-associated (HAP) and ventilator-associated (VAP) pneumonia.  Luckily, they didn’t change anything earth-shattering, just tightened them up a bit.  Antibiotic regimens are below and they recommend 7-days total of therapy.

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2016 IDSA/ATS Guidelines

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2016 IDSA/ATS Guidelines


References

#16 – Pneumonia



 

Classifications of Pneumonia

  • Community-Acquired (CAP)
  • Healthcare-Associated (HAP)
    • Any IV therapy, wound care, or chemotherapy within 20 days
    • Resident of nursing home or other long term care facility
    • Hospitalization for ≥ 2 days within 90 days
    • Visit to outpatient clinic or hemodialysis within 30 days
  • Ventilator-Associated (VAP)
    • Currently or previously intubated during current hospitalization

Epidemiology

  • 6 cases per 1000 persons per year (~ 5 million cases per year)
  • Top 10 in mortality in US (~60,000 deaths/year)
  • 12% 30-day mortality in patients requiring admission
  • 28% all-cause mortality within one year

 

Pathogenesis

4 phases of development

  • Edema
    • Proteinaceous exudate in the alveoli
    • Bacteria accumulation
  • Red hepatization
    • Erythrocyte extravasation
  • Grey hepatization
    • Neutrophil extravasation with bacterial clearance
  • Resolution
    • Macrophage proliferation with inflammatory response

 

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Murthy SV. Pathology of Pneumonia. SlideShare.

Risk Factors

  • Age
  • Winter months
  • Increased risk of aspiration (AMS, CVA, intoxication, seizures)
  • Smoking
  • Underlying pulmonary disease (Asthma, COPD, cancer)
  • Immunosupression
  • Viral URI
  • Decreased host defenses (impaired ciliary clearance)
  • Acid-reducing medications
  • Malnutrition
  • Inhalation exposures
2

Up To Date. 2016.

 

Pathogens

  • Viral (most common)
    • Rhinovirus (most common)
    • Influenza
    • Adenovirus
    • Respiratory Syncytial Virus (RSV)
  • Bacterial
    • S. pneumoniae (most common CAP)
    • H. influenza
    • M. pneumoniae (most common atypical)
    • K. pneumoniae (tends to be more severe)
    • Legionella
    • ESKAPE bugs (>80% of VAP)
      • Enterococcus
      • Staphylococcus
      • Klebsiella
      • Acinetobacter
      • Pseudomonas
      • Enterobacter
  • Fungal (immunocompromised)
    • Histoplasmosis
    • Cryptococcus
    • Coccidioides
    • Blastomycosis
    • Aspergillus

Signs and Symptoms

  • Productive cough
  • Fever
  • Chills and/or rigors
  • Dyspnea
  • Pleuritic chest pain
  • Nausea/vomiting
  • Altered mental status

 

Physical Exam Findings

  • Vital signs
    • Febrile (elderly may not mount a response)
    • Tachycardic
    • Tachypnic
  • Pulmonary
    • Rales and/or rhonchi
    • Signs of consolidation
      • Decreased breath sounds
      • Dullness to percussion
      • Increased tactile fremitus
      • Egophany
      • Whispered pectoriliquoy

 

Radiographic Evaluation

  • Bacterial
    • Unilateral, lobar, air bronchograms

3

  • Viral
    • Diffuse or perihilar, bilateral

4

Laboratory Evaluation

  • CBC with differential
  • Blood cultures
  • Sputum culture and gram stain
    • Good sample = PMNs with < 10 squamous cells per LPF
  • Urine antigen (pneumococcal and Legionella)
  • Multiplex PCR
5

Up To Date. 2016.

Should They Stay or Should They Go Now????

  • Pneumonia Severity Index (PSI)
    • Step 1
      • If none of the following, then Class I and outpatient treatment
        • Age > 50 years
        • Neoplastic disease
        • Heart failure
        • Cerebrovascular disease
        • Renal disease
        • Liver disease
        • Altered mental status
        • HR ≥ 125/min
        • RR ≥ 30/min
        • SBP ≤ 90 mmHg
        • Temperature ≤ 35oC or ≥ 40oC
    • Step II
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Step II of PSI/PORT Score for Risk Stratification

  • CURB-65 Score
    • 5 variables
      • Confusion
      • Urea (BUN ≥ 20 mg/dL)
      • Respiratory rate ≥ 30/min
      • Blood pressure (SBP < 90 mmHg or DBP < 60 mmHg)
      • Age ≥ 65 years
    • Interpretation
      • Score 0-1 = Outpatient management
      • Score 2-3 = Inpatient management
      • Score 4-5 = ICU management
  • SMART-COP Score
    • Used to predict need for respiratory or vasopressor support

6

 

Treatment

  • Care should be taken to think about patients with risk factors for drug-resistant S. pneumoniae:
    • Age > 65 years
    • Beta-lactam, macrolide, or fluouroquinolone in the past 3-6 months
    • Alcoholism
    • Medical comorbidities
    • Immunosuppression
    • Exposure to child in daycare
  • Community-Acquired
7

Treatment for Community-Acquired Pneumonia. IDSA/ATS 2007 Guidelines.

  • Healthcare-Associated
8

Treatment of Healthcare-Associated Pneumonia. IDSA/ATS 2007 Guidelines.


Cottage Physician

CottageMD

Cottage Physician. 1893.


References

  1. Mandell LA, Wunderink RG. Pneumonia. In: Kasper D, Fauci A, Hauser S, Longo D, Jameson J, Loscalzo J. eds. Harrison’s Principles of Internal Medicine, 19e. New York, NY: McGraw-Hill; 2015. http://accessmedicine.mhmedical.com/content.aspx?bookid=1130&Sectionid=79733578. Accessed July 11, 2016.
  2. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. American journal of respiratory and critical care medicine. 171(4):388-416. 2005. [pubmed]
  3. File TM, Marrie TJ. Burden of community-acquired pneumonia in North American adults. Postgraduate medicine. 122(2):130-41. 2010. [pubmed]
  4. Murthy SV. Pathology of Pneumonia.    http://www.slideshare.net/vmshashi/pathology-of-pneumonia.  Accessed on July 11,  2016.
  5. Almirall J, Bolíbar I, Balanzó X, González CA. Risk factors for community-acquired pneumonia in adults: a population-based case-control study. The European respiratory journal. 13(2):349-55. 1999. [pubmed]
  6. Mandell LA, Wunderink RG, Anzueto A. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 44 Suppl 2:S27-72. 2007. [pubmed]
  7. Musher DM, Thorner AR. Community-acquired pneumonia. The New England journal of medicine. 371(17):1619-28. 2014. [pubmed]
  8. Jain S, Self WH, Wunderink RG. Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults. The New England journal of medicine. 373(5):415-27. 2015. [pubmed]
  9. Metlay JP, Kapoor WN, Fine MJ. Does this patient have community-acquired pneumonia? Diagnosing pneumonia by history and physical examination. JAMA. 278(17):1440-5. 1997. [pubmed]
  10. Fine MJ, Auble TE, Yealy DM. A prediction rule to identify low-risk patients with community-acquired pneumonia. The New England journal of medicine. 336(4):243-50. 1997. [pubmed]
  11. Lim WS, van der Eerden MM, Laing R. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 58(5):377-82. 2003. [pubmed]
  12. Charles PG, Wolfe R, Whitby M. SMART-COP: a tool for predicting the need for intensive respiratory or vasopressor support in community-acquired pneumonia. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 47(3):375-84. 2008. [pubmed]
  13. Pugh R, Grant C, Cooke RP, Dempsey G. Short-course versus prolonged-course antibiotic therapy for hospital-acquired pneumonia in critically ill adults. The Cochrane database of systematic reviews. 2015. [pubmed]

Answer to Pulmonary Question

The diagnostic criteria for acute respiratory distress syndrome (ARDS) are the Berlin Criteria.

  1. Timing – within 7 days of a known clinical insult or worsening respiratory symptoms
  2. Imaging – Bilateral opacities not fully explained by effusions, atelectasis, or masses/nodules
  3. Absence of cardiac failure or fluid overload
  4. Hypoxemia – PaO2/FiO2 ≤ 300 mmHg with PEEP/CPAP ≥ 5 cmH2O

 

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Reference

  1. ARDS Definition Task Force.  Acute Respiratory Distress Syndrome – The Berlin Definition.  JAMA. 2012;307(23):2526-2533.
  2. PulmCCM Blog.  Meet the New ARDS: Expert panel announces new definition, severity classes.
  3. Life In The Fastlane Blog.  ARDS Definition.