Acute dyspnea: Difference between revisions

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==Workup==
{{AdultPage|acute dyspnea (peds)}}
==Background==
*Dyspnea (shortness of breath) is one of the most common ED chief complaints<ref>Mueller C, et al. Use of B-type natriuretic peptide in the evaluation and management of acute dyspnea. N Engl J Med. 2004;350(7):647-654. PMID 14960741</ref>
*Can be life-threatening — rapid assessment for immediately dangerous causes is essential
*The approach should focus on pattern recognition using vital signs, lung exam, CXR, and ECG to quickly narrow the differential
*Key question: Is this cardiac, pulmonary, or other?
[[File:Lung and diaphragm.jpg|thumb|Lobes of the lung with related anatomy.]]


==Clinical Features==
===Emergent Pattern Recognition===
{| class="wikitable"
| align="center" style="background:#f0f0f0;"|'''Diagnosis'''
| align="center" style="background:#f0f0f0;"|'''Lungs'''
| align="center" style="background:#f0f0f0;"|'''[[CXR]]'''
| align="center" style="background:#f0f0f0;"|'''[[ECG]]'''
| align="center" style="background:#f0f0f0;"|'''Treatment'''
| align="center" style="background:#f0f0f0;"|'''Contraindicated'''
|-
| [[Pulmonary Edema]]||Bilateral rales||Interstitial fluid||Normal/abnormal||R/O AMI, [[lasix]], nitrates, [[ACEi]], [[BiPAP]]||[[IVF]]; ?[[albuterol]]; ?[[Beta-blockers]]
|-
| [[Bronchoconstriction]]||Wheezes||Clear/hyperinflated||Normal/pulmonary strain||Albuterol, atrovent, steroids, consider anaphylaxis (epi)||Beta-blockers; ?aspirin
|-
| [[Pneumonia]]||Focal ronchi/decreased breath sounds||Infiltrate/effusion||Normal||[[IVF]], [[antibiotics]]||Rate control; diuresis
|-
| [[Pulmonary embolism]]||Clear||Clear (most) or Westrmark/Hampton hump||Normal/S1Q3T3||Anticoagulate/[[thrombolytics]]||Rate control
|-
| [[Pneumothorax]]/[[Hemothorax]]||Unequal||Pneumo/hemo||Normal||Needle [[thoracentesis]]/[[chest tube]]||Rate control
|-
| [[Dysrythmia]]||Clear/pulmonary edema||Clear/pulmonary edema||Abnormal||Type dependent||[[Albuterol]]; ?[[IVF]]
|-
| [[ACS]]||Clear/pulmonary edema||Clear/pulmonary edema||Normal/abnormal||[[Aspirin]]; nitrates, anticoagulation, ?[[beta-blockers]], +/- [[thrombolytics]]||[[Albuterol]]; ?[[IVF]]
|}


CXR
==Differential Diagnosis==
{{SOB DDX}}


ECG
==Evaluation==
[[File:PulmEdema.png|thumb|Pulmonary edema with small pleural effusions on both sides.]]
===Immediate===
*Pulse oximetry (continuous)
*[[ECG]] — arrhythmia, ischemia, RV strain
*[[CXR]] — pneumothorax, effusion, pulmonary edema, consolidation, widened mediastinum
*[[Point-of-care ultrasound|Bedside ultrasound]] — pneumothorax, pleural effusion, B-lines (pulmonary edema), pericardial effusion, RV dilation, cardiac contractility


CBC
===Labs (guided by clinical suspicion)===
*[[BNP]]/NT-proBNP — helps differentiate cardiac from pulmonary dyspnea
*[[Troponin]] — if ACS suspected
*[[D-dimer]] — if PE suspected and low-to-moderate pretest probability
*CBC — anemia, infection
*BMP — metabolic acidosis (consider DKA, sepsis, toxic ingestion)
*VBG/ABG — acid-base status, pCO2, carboxyhemoglobin, methemoglobin
*Lactate — if sepsis or shock suspected


Chem 7
===Advanced Imaging===
*[[CT-PA]] — if pulmonary embolism suspected
*CT chest — if parenchymal disease, mass, or empyema suspected
*CT angiography — if aortic dissection suspected


{{BLUE Protocol}}


Consider:
==Management==
*'''Oxygen:''' Titrate to SpO2 >94% (88-92% if COPD/CO2 retainer); use high-flow nasal cannula, [[BiPAP]], or intubation as needed
*Immediate life threats:
**[[Tension pneumothorax]]: Needle decompression then chest tube
**[[Anaphylaxis]]: [[Epinephrine]] IM
**[[Cardiac tamponade]]: Pericardiocentesis
**Massive [[PE]]: Systemic thrombolytics
*Common causes:
**[[CHF]] exacerbation: [[Nitroglycerin]], [[BiPAP]], [[furosemide]]
**[[Asthma]]/[[COPD exacerbation]]: [[Albuterol]], ipratropium, systemic steroids
**[[Pneumonia]]: Antibiotics, IVF
**[[PE]]: Anticoagulation
*Airway management:
**[[BiPAP]] for CHF or COPD exacerbation (avoids intubation in many cases)
**Intubation if impending respiratory failure, GCS decline, or refractory hypoxia


BNP
==Disposition==
*Admit to ICU:
**Intubated or on BiPAP with impending respiratory failure
**Massive or submassive PE
**Hemodynamic instability
**Severe asthma/COPD unresponsive to initial treatment
*Admit to floor:
**CHF exacerbation requiring IV diuresis
**Pneumonia with hypoxia or significant comorbidities
**New PE on anticoagulation
*Discharge:
**Asthma/COPD exacerbation with adequate response to ED treatment and baseline PEF restored
**Mild CHF exacerbation with adequate response to diuresis and stable vitals
**Low-risk PE (if outpatient anticoagulation pathway available)
**Anxiety-related dyspnea after exclusion of organic causes


D-dimer
== Calculators ==
{{Aa Gradient Calculator}}


Troponin
==See Also==
*[[Hypoxemia]]
*[[Shortness of breath (peds)]]


==References==
<References/>


ABG
[[Category:Cardiology]]
 
[[Category:Pulmonary]]
[[Category:Symptoms]]
 
==Diagnosis==
 
 
EMERGENT PATERN RECOGNITION
 
1) Pulmonary edema
 
    -lungs: bilat rales
 
    -CXR: interstitial fluid
 
    -Tx: ECG (R/O AMI), lasix, nitrates, ACE, BIPAP
 
2) Bronchoconstriction
 
    -lungs: wheezes
 
    -CXR: neg/hyperinflated
 
    -Tx: albuterol, atrovent, steroids, consider anaphylaxis (antihistamines, epi)
 
3) Pneumonia
 
    -lungs: focal ronchi/dec BS
 
    -CXR: infiltrate/effusion
 
    -Tx: abx, goal directed,
 
4) PE
 
    -lungs: clear
 
    -CXR: clear/Westrmrk/Hmptn
 
    -Tx: ECG, D-dimer and/or spiral CT; anticoagulate/thrombolise
 
5) Pneumo/Hemo-Thorax
 
    -lungs: unequal
 
    -CXR: pneumo/hemo
 
    -Tx: needle/chest-tube
 
6) Dysrythmia
 
    -lungs: clear/pulm edema
 
    -CXR: clear/pulm edema
 
    -ECG: abnl
 
    -Tx: rate dependent
 
7) Cardiac Ischemia
 
    -lungs: clear/pulm edema
 
    -CXR: clear/pulm edema
 
    -ECG: nl/abnl
 
    -Tx: B-block, nitrates, anticoag, +/- thrombolitics
 
 
*Consider ABG
 
 
==DDX==
 
 
EMERGENT
 
A. Pulmonary
 
    1) Airway obstruction
 
    2) PE
 
    3) Noncardiogenic edema
 
    4) Anaphylaxis
 
    5) Spont pneumothorax
 
    6) Asthma
 
    7) Cor pulmonale
 
    8) Aspiration
 
    9) PNA
 
B. Cardiac
 
    1) Pulmonary edema (CHF)
 
    2) MI
 
    3) Cardiac tamponade
 
    4) Pericarditis
 
C. Other Associated with Nl/Increased Resp Effort
 
    1) Toxic ingestion
 
    2) DKA
 
    3) Epiglotitis
 
    4) Tension PNTX
 
    5) Cardiac tamponade
 
    6) Flail chest
 
    7) CO poisoning
 
    8) Abd distension
 
    9) Sepsis
 
    10) Hypotension
 
    11) Renal failure
 
    12) Electrolyte abnl
 
    13) Metabolic acidosis
 
    14) PNA
 
    15) Pneumo/hemo-thorax
 
    16) Diaphragmatic rupture
 
    17) Anemia
 
D. Other Associated with Decreased Resp Effort
 
    1) CVA
 
    2) Organophosphate poisoning
 
    3) MS
 
    4) Guillian-Barre
 
    5) Tick paralysis
 
 
Non-Emergent
 
1) Pleural effusion
 
2) Neoplam
 
3) PNA
 
4) COPD
 
5) Congenital heart dz
 
6) Pregnancy
 
7) Ascites
 
8) Obesity
 
9) Hypterventilation
 
10) Panic attack
 
11) Fever
 
12) Thyroid dz
 
13) Rib fx
 
14) ALS
 
15) Polymyositis
 
16) Porphyria
 
 
==Source==
 
 
3/7/06 DONALDSON (adapted from Rosen)
 
 
 
 
[[Category:Pulm]]

Latest revision as of 10:09, 22 March 2026

This page is for adult patients. For pediatric patients, see: acute dyspnea (peds)

Background

  • Dyspnea (shortness of breath) is one of the most common ED chief complaints[1]
  • Can be life-threatening — rapid assessment for immediately dangerous causes is essential
  • The approach should focus on pattern recognition using vital signs, lung exam, CXR, and ECG to quickly narrow the differential
  • Key question: Is this cardiac, pulmonary, or other?
Lobes of the lung with related anatomy.

Clinical Features

Emergent Pattern Recognition

Diagnosis Lungs CXR ECG Treatment Contraindicated
Pulmonary Edema Bilateral rales Interstitial fluid Normal/abnormal R/O AMI, lasix, nitrates, ACEi, BiPAP IVF; ?albuterol; ?Beta-blockers
Bronchoconstriction Wheezes Clear/hyperinflated Normal/pulmonary strain Albuterol, atrovent, steroids, consider anaphylaxis (epi) Beta-blockers; ?aspirin
Pneumonia Focal ronchi/decreased breath sounds Infiltrate/effusion Normal IVF, antibiotics Rate control; diuresis
Pulmonary embolism Clear Clear (most) or Westrmark/Hampton hump Normal/S1Q3T3 Anticoagulate/thrombolytics Rate control
Pneumothorax/Hemothorax Unequal Pneumo/hemo Normal Needle thoracentesis/chest tube Rate control
Dysrythmia Clear/pulmonary edema Clear/pulmonary edema Abnormal Type dependent Albuterol; ?IVF
ACS Clear/pulmonary edema Clear/pulmonary edema Normal/abnormal Aspirin; nitrates, anticoagulation, ?beta-blockers, +/- thrombolytics Albuterol; ?IVF

Differential Diagnosis

Acute dyspnea

Emergent

Non-Emergent

Evaluation

Pulmonary edema with small pleural effusions on both sides.

Immediate

  • Pulse oximetry (continuous)
  • ECG — arrhythmia, ischemia, RV strain
  • CXR — pneumothorax, effusion, pulmonary edema, consolidation, widened mediastinum
  • Bedside ultrasound — pneumothorax, pleural effusion, B-lines (pulmonary edema), pericardial effusion, RV dilation, cardiac contractility

Labs (guided by clinical suspicion)

  • BNP/NT-proBNP — helps differentiate cardiac from pulmonary dyspnea
  • Troponin — if ACS suspected
  • D-dimer — if PE suspected and low-to-moderate pretest probability
  • CBC — anemia, infection
  • BMP — metabolic acidosis (consider DKA, sepsis, toxic ingestion)
  • VBG/ABG — acid-base status, pCO2, carboxyhemoglobin, methemoglobin
  • Lactate — if sepsis or shock suspected

Advanced Imaging

  • CT-PA — if pulmonary embolism suspected
  • CT chest — if parenchymal disease, mass, or empyema suspected
  • CT angiography — if aortic dissection suspected


Bedside Lung Ultrasound in Emergency (BLUE) Protocol[2]

Algorithm for the Use of Ultrasound in the Evaluation of Dyspnea
  • Landmark study by a French intensivist that described various profiles of specific pulmonary disease found on US[3]
  • Ultrasound approaches include anterior zones and PLAPS (posterior or lateral alveolar and/or pleural syndrome) point, which is located at the posterior axillary line similar to FAST view
  • Predominant A lines anteriorly + lung sliding = Asthma/COPD
  • Multiple predominant B lines anteriorly + lung sliding = Pulmonary Edema
  • Predominant A lines anteriorly + lung sliding + positive DVT = PE
  • Absent anterior lung sliding + anterior A lines + positive lung point = Pneumothorax (PTX)
  • PLAPS findings +/- A or B lines +/- abolished lung sliding = Pneumonia
    • PLAPS describes changes at the PLAPS point, usually related to consolidations and pleural effusions[4]
    • Consolidations may include lung hepatization, shred sign, air bronchograms
      • Note that mirroring (normal) may appear similar to hepatization, but mirroring only shows in specific spots due to specific echogenic windows
    • Pleural effusions are visualized as anechoic/hypoechoic areas with possible spine sign or floating lung sign (sinusoid sign on M-mode)
  • A suggested BLUE protocol guides diagnosis of dyspnea; this should be modified as needed based on clinical presentation
    • Check lung sliding in anterior lung fields ---> check for A and B lines ---> check for PLAPS findings

Management

Disposition

  • Admit to ICU:
    • Intubated or on BiPAP with impending respiratory failure
    • Massive or submassive PE
    • Hemodynamic instability
    • Severe asthma/COPD unresponsive to initial treatment
  • Admit to floor:
    • CHF exacerbation requiring IV diuresis
    • Pneumonia with hypoxia or significant comorbidities
    • New PE on anticoagulation
  • Discharge:
    • Asthma/COPD exacerbation with adequate response to ED treatment and baseline PEF restored
    • Mild CHF exacerbation with adequate response to diuresis and stable vitals
    • Low-risk PE (if outpatient anticoagulation pathway available)
    • Anxiety-related dyspnea after exclusion of organic causes

Calculators

A-a O₂ Gradient

Alveolar-arterial (A-a) O₂ Gradient
Parameter Value
Age (years)
FiO₂ (%)
PaCO₂ (mmHg)
PaO₂ (mmHg)
A-a Gradient mmHg
Expected A-a mmHg (age-adjusted normal)
Interpretation
  • Normal A-a gradient ≈ (Age/4) + 4 on room air
  • Elevated A-a gradient suggests: V/Q mismatch, shunt, or diffusion impairment
  • Normal A-a gradient + hypoxia suggests: hypoventilation or low FiO₂
References
  • Formula: A-a = [FiO₂ × (Patm – PH2O)] – (PaCO₂/0.8) – PaO₂
  • Kanber GJ, et al. The alveolar-arterial oxygen gradient in young and elderly men during air and oxygen breathing. Am Rev Respir Dis. 1968;97(3):376-381. PMID 5637791.

See Also

References

  1. ↑ Mueller C, et al. Use of B-type natriuretic peptide in the evaluation and management of acute dyspnea. N Engl J Med. 2004;350(7):647-654. PMID 14960741
  2. ↑ http://ccm.anest.ufl.edu/files/2012/08/BLUELung.pdf Relevance of Lung Ultrasound in the Diagnosis of Acute Respiratory Failure - The BLUE Protocol
  3. ↑ Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest. 2008 Jul;134(1):117-25. doi: 10.1378/chest.07-2800. Epub 2008 Apr 10. Erratum in: Chest. 2013 Aug;144(2):721. PMID: 18403664; PMCID: PMC3734893.
  4. ↑ Lichtenstein DA. Lung ultrasound in the critically ill. Ann Intensive Care. 2014 Jan 9;4(1):1. doi: 10.1186/2110-5820-4-1. PMID: 24401163; PMCID: PMC3895677.
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