Acute dyspnea: emergency diagnosis and treatment

2021-08-03 10:54 PM

Shortness of breath is a common symptom, caused by lung disease, myocardial ischemia or dysfunction, anemia, neuromuscular disorders, obesity

Shortness of breath is an unusual, uncomfortable feeling when breathing. This is a completely subjective feeling described by the patient.

Shortness of breath is considered acute when it develops over hours to days and chronic when it has been more than four to eight weeks. Some patients present with chronic worsening of dyspnea that may be due to a new problem or an aggravation of an underlying disease (eg, asthma, chronic obstructive pulmonary disease, heart failure).

The mechanism that causes dyspnea is not completely understood. This condition is mainly seen in situations with increased respiratory work (obstruction in the airways, changes in pulmonary compliance, hypoxia, anemia), when the patient is in a state of anxiety or distress. respiratory muscle paralysis or neuromuscular block.

Some situations may be associated with dyspnea, but it is not synonymous with dyspnea such as changes in breathing rate or amplitude: hyperventilation due to metabolic acidosis, Cheyne-Stockes breathing.

In fact, shortness of breath is often the main symptom of heart and lung disease II. There is a strong link between the degree of shortness of breath and the cause of the disease.

Diagnosis of acute dyspnea

Diagnosis is based on the patient's medical history (note that dyspnea is a subjective feeling of the patient) and indirect signs of dyspnea:

The patient's feeling of shortness of breath: feeling of lack of air to breathe, feeling tired when breathing, uncomfortable when breathing...

Manifestations of breathing effort (rapid breathing, respiratory muscle contractions, paradoxical chest and abdomen breathing ...), having to sit to breathe, nostrils rising and falling, opening mouth to breathe...

Other suggestive clinical signs:

Breathe with a hissing sound.

+ Purple, sweating.

+ Breathing disorders: fast or slow breathing, breathing Kussmaul, Cheyne Stocks.

Strong, noisy breathing or weak, shallow breathing.

Cardiac arrhythmia: fast or slow or irregular heartbeat.

+ Change in blood pressure: BP increases or decreases.

Consciousness disturbance in very severe cases: agitation, confusion to somnolence, coma.

Diagnosis of acute dyspnea

It is difficult to objectively determine the degree of dyspnea. There are several ways to determine the level:

+ Dyspnea score: ask the patient to estimate the degree of dyspnea from 0 to 10 (same for pain score).

+ Determine the degree of exertion causing dyspnea, classified from mild to severe: at rest, with mild exertion (eg, walking around the house), with moderate exertion (climbing stairs, record the number of floors the patient can climb), heavy exertion (eg, running, record the distance the patient can run).

Some situations are immediately identified as severe or critical without taking time to assess the degree of dyspnea:

+ Currently in respiratory failure (need to assess the degree of respiratory failure).

+ The pulse is collapsing.

Consciousness disturbance.

+ Breathing with laryngeal dyspnea-like stridor (evaluate the degree of dyspnea individually - see upper airway obstruction emergency).

Orientation to diagnose the cause of acute dyspnea

Some causes need to be discovered quickly

Laryngeal dyspnea, upper airway obstruction (see Upper airway obstruction).

Pressure pneumothorax.

Cardiac tamponade due to pericardial effusion.

Anaphylaxis (see anaphylaxis).

The clinical examination helps guide the diagnosis of some causes such as:

The clinical picture of laryngeal dyspnea due to obstruction in the larynx is a vital emergency for the patient.

Diagnosis is based on: dyspnea on inspiration, respiratory traction, sometimes stridor, hoarseness or loss of voice.

Look for severe clinical signs: signs of acute respiratory failure, exhaustion, the patient must be in a sitting position.

The above clinical picture may be caused by:

+ Foreign body in the airway: occurs while eating, in an elderly person.

+ Epiglottitis due to bacterial infection.

+ Quink's edema: allergic disease.

+ Due to tumor: shortness of breath increases gradually in patients over 55 years old who smoke.

Laryngeal trauma.

+ Sequelae of endotracheal intubation or tracheostomy.

Shortness of breath associated with chest pain can be caused by:

+ Pulmonary infarction: diagnosis in emergency situations is often difficult: signs of thrombophlebitis are variable and subtle such as rapid pulse. Do some emergency tests (electrocardiogram, radiograph, arterial blood gases, quantification of D-dimers) that provide evidence to guide or rule out the diagnosis before deciding to order imaging studies. more in-depth images.

+ Left ventricular failure associated with ischemic heart disease: look for signs of ischemia on the electrocardiogram (change of ST and T).

+ Spontaneous pneumothorax: sudden chest pain, usually occurs in young people. Clinical examination to detect pneumothorax. Diagnosis is based on a straight chest x-ray during inspiration.

+ Pleurisy: diagnosis is based on the characteristics of chest pain (maybe nonspecific): pain increases with inspiration. Clinical examination revealed: triple reduction syndrome. Confirm the diagnosis by chest x-ray straight and inclined.

If fever is present, it should be directed to infectious causes:

+ Pneumonia: localized crackles are heard with tube murmur, sometimes the patient spits up purulent sputum. Chest X-ray is the basic test to confirm the diagnosis and can provide the etiology: pneumococcal lobar pneumonia, interstitial lung disease, pulmonary tuberculosis.

+ Bronchitis: cough, purulent sputum.

Impaired consciousness or neurologic disease suggestive of aspiration pneumonia, which should be confirmed by radiographs and even flexible bronchoscopy (if possible). ).

The altered general condition suggests a cancerous etiology (especially when the patient has progressive dyspnea or tuberculosis (cough, fever, atopic). The chest x-ray is the basic test in guiding the diagnosis.

An asthma attack is usually easy to diagnose: a well-known history, sudden onset of dyspnea, dyspnea with crackles. In the primary care setting, it is essential to detect and recognize the signs that assess the severity of an asthma attack.

Acute cardiac pulmonary edema: history of pre-existing heart disease (ischemic cardiomyopathy, valvular disease, cardiomyopathy). The dyspnea usually occurs at night, with moist rales heard in both lung fields, which may progress rapidly on examination. Chest radiograph (butterfly opacity, diffuse alveolar edema on both sides, sometimes Kerley B lines or redistribution of blood vessels toward the apex) but emergency management should not be delayed in diagnosis. clear clinical diagnosis.

Acute pulmonary edema (ARDS) is preceded by acute respiratory failure associated with severe hypoxemia, chest x-ray shows lesion-type pulmonary edema (white lungs on both sides), no signs of respiratory failure. left heart.

Several acute and severe conditions encountered in many different situations are likely to cause this severe lung injury:

+ Lung damage: infectious lung disease, inhalation of toxic gas, gastric juice, drowning, lung contusion.

+ Extrapulmonary disease: severe infection, acute pancreatitis, multiple traumata, fatty embolism...

+ It is necessary to immediately transfer the patient to the intensive care unit for active treatment with specialized measures.

Most episodes of dyspnea seen in the emergency department are manifestations of acute decompensation of chronic obstructive pulmonary disease (see section Chronic Obstructive Pulmonary Disease).

Emergency treatment of acute difficulty breathing

The initial goal is good control of vital functions (ABC) and prompt emergency management of some dangerous causes.

Open the airways

Protruding neck.

Canun Guedel or Mayo against tongue drop.

Suction sputum, suction bronchial lavage.

The side position is safe if there is a risk of choking.

Heimlich test if present. airway object.

Endotracheal intubation (or tracheal opacification): an effective means of opening the airway.

Breathe O2

Nasal cannula: FiO 2 max gain = 0.4 (61 / min).

Mask: = 0.6 (81/min).

Mask with reserve shadow: = 0.8 (91/min).


Increased risk of CO 2 due to breathing 0 2 high doses in patients with COPD has not been artificial ventilation (breathing should be <21 / min).

Need to monitor: SpO 2 + blood gas + clinical.

Artificial ventilation

Squeeze balloons give breaths: pay attention to flex the patient's neck if not intubated.

Machine artificial ventilation

Through the mask.

Through endotracheal tube/tracheostomy.

Pay attention

SPO 2 - arterial blood gases.


Risk of pneumothorax.

Risk of nosocomial lung infections.

Detect and drain dangerous cases of pneumothorax, pay special attention to the following cases

Tension pneumothorax, bilateral pneumothorax.

Pneumothorax/diffuse or contralateral lung injury.


Pneumothorax/Artificial ventilation.


Bronchodilators: aerosol; Intravenous.

Expectorants: should only be given when the patient is still coughing or after the tube has been inserted.

Corticosteroids: bronchial asthma, laryngeal edema, exacerbation of COPD.

Diuretic, antihypertensive: acute pulmonary edema, heart failure, ...

Treat the cause: depending on antibiotics, anticoagulation...