OVERVIEW

What is Acute Respiratory Distress Syndrome (ARDS)?

As we know, the lungs are the respiratory organs of the human body. The alveoli are closely connected to the pulmonary capillaries, working in coordination to supply oxygen to the body and expel carbon dioxide.

Acute Respiratory Distress Syndrome refers to acute diffuse lung injury and subsequent acute respiratory failure caused by various pathogenic factors. It is characterized pathologically by alveolar-capillary damage, manifesting as refractory hypoxia that generally cannot be alleviated by oxygen therapy.

ARDS is the abbreviation for the full English name of Acute Respiratory Distress Syndrome.

How common is Acute Respiratory Distress Syndrome?

According to a 2005 study, the incidence of ARDS is 59 per 100,000 people annually. The incidence varies depending on the underlying cause. For example, 1/4 to 1/2 of patients with severe infections may develop ARDS. The incidence rates for ARDS caused by massive blood transfusion, multiple trauma, and aspiration are 40%, 15%–25%, and 9%–26%, respectively.

SYMPTOMS

What are the manifestations of acute respiratory distress syndrome?

The most common manifestation is increased respiratory rate, often accompanied by an elevated heart rate. Patients subjectively feel shortness of breath and difficulty breathing.

For elderly individuals who cannot communicate, physical changes can be observed.

Severe respiratory distress may cause bluish lips and nails. Desperate inhalation may lead to supraclavicular, suprasternal, and intercostal retractions (known as "three depressions sign"). Other symptoms may include chest tightness, dizziness, coughing, blurred vision, profuse sweating, and fainting.

Can acute respiratory distress syndrome be diagnosed based on rapid breathing alone?

Besides ARDS, many other conditions can cause rapid breathing, such as pneumonia, heart failure, epiglottitis, and asthma.

Doctors make a comprehensive judgment based on medical history, symptoms, and examinations. Accurate diagnosis facilitates timely treatment.

For ARDS, damage to the alveolar epithelium and capillary membrane must be present, as this is the pathological hallmark of the disease.

Only by understanding this pathological feature can misdiagnosis be reduced and targeted treatment be implemented.

What are the types of acute respiratory distress syndrome?

It can be classified by the primary affected organ into pulmonary (e.g., pneumonia, drowning, aspiration) and extrapulmonary (e.g., pancreatitis, systemic infection, shock). It can also be categorized into biological causes (e.g., bacteria, viruses, fungi) and non-biological causes (e.g., acidic substances, drugs, toxic gases).

What symptoms might acute respiratory distress syndrome present?

Patients often experience chest tightness and severe breathlessness, i.e., respiratory distress, which cannot be alleviated by conventional oxygen therapy.

Symptoms include rapid breathing, bluish lips and fingertips, chest tightness, coughing, hemoptysis, impaired consciousness, multi-organ dysfunction, and even death.

Is it difficult to expel carbon dioxide, a waste gas, in acute respiratory distress syndrome?

In severe ARDS, the effective gas exchange area of the lungs decreases, leading to impaired carbon dioxide elimination.

Thus, in patients with respiratory distress, the inability to expel carbon dioxide (indicated by elevated arterial carbon dioxide levels) is a sign of worsening disease.

What does it mean when a doctor says "the lungs have turned white"?

On a chest X-ray, normal lungs appear "black" due to their air-filled state.

If the lungs show "white" areas, it indicates that alveoli are filled with substances, primarily fluid-based "debris."

This "debris" interferes with the exchange of oxygen and carbon dioxide between the body and the atmosphere. Doctors often refer to "white lungs" to describe extensive bilateral lung involvement.

ARDS may exhibit "white lung" signs, but this can also occur in various types of pulmonary edema or other conditions.

If "white lungs" appear during ARDS progression, it often indicates severe disease, but the condition may normalize with improvement.

What situations during hospitalization for acute respiratory distress syndrome should prompt notifying a doctor or nurse?

ARDS is a critical condition. If in an ICU, specialized doctors and nurses will manage the patient.

If in a general ward, patients or family members should notify medical staff immediately if symptoms worsen, such as increased breathing difficulty, cyanosis, palpitations, cold sweats, dizziness, nausea, or vomiting.

Are there any sequelae after recovery from acute respiratory distress syndrome?

Some patients may experience excessive repair, leading to pulmonary fibrosis, which reduces lung gas exchange capacity and decreases exercise tolerance.

However, others may recover almost completely, resuming normal life and daily activities.

CAUSES

Is Acute Respiratory Distress Syndrome contagious?

ARDS itself is not contagious, but if it is caused by pneumonia, influenza, or severe infections, the pathogens may spread to others.

If these pathogens damage the alveolar-capillary membrane in another person's lungs, they may also develop ARDS.

What causes Acute Respiratory Distress Syndrome?

The lungs are directly connected to the external environment through the trachea and bronchi, so harmful microorganisms or toxins from outside can attack the alveoli and alveolar capillaries.

Additionally, the lungs are like a massive "capillary network," as almost all blood in the body passes through them. Therefore, certain non-pulmonary diseases can also damage the alveolar capillaries via circulating harmful factors, leading to ARDS.

Is ARDS an overreaction of the lungs to disease?

To some extent, this analogy is fitting. When pathogens or inflammatory factors reach the lungs, they may be cleared, leading to recovery. However, these harmful factors can also trigger excessive recruitment of inflammatory cells to the lungs (overreaction). Often, this response fails to eliminate the pathogens but instead damages the alveolar capillaries, causing breathing difficulties.

Once this reaction starts, anti-inflammatory hormones alone are usually ineffective. At certain stages of disease progression, some drugs may help prevent its onset, but specific medications to suppress this overreaction are still under research.

Who is at higher risk of developing ARDS?

People with the following conditions or exposure to certain hazardous environments are more susceptible: pneumonia (e.g., notorious infections like SARS or avian flu), aspiration, lung contusion, drowning, inhalation of toxic substances, severe systemic infections, major trauma, shock, high-risk surgeries, massive blood transfusions, drug poisoning, pancreatitis, etc.

Are ARDS and Middle East Respiratory Syndrome the same?

Middle East Respiratory Syndrome is essentially a viral pneumonia. Some patients may be asymptomatic (carriers), while others may have mild or severe symptoms. Among severe cases, if the alveolar-capillary membrane is damaged, ARDS can develop.

DIAGNOSIS

What tests are needed to diagnose acute respiratory distress syndrome?

The diagnosis of ARDS is primarily clinical. When doctors observe that a patient's hypoxia is difficult to correct, ARDS should be considered. Clinically, further confirmation is made through chest X-rays or CT scans, blood gas analysis, pulmonary artery catheter monitoring, ultrasound, and other examinations.

Which diseases can acute respiratory distress syndrome be easily confused with?

It may be confused with other conditions causing dyspnea, such as acute heart failure, acute myocardial infarction, pulmonary embolism, pulmonary fibrosis, asthma, pneumothorax, massive pleural effusion, or airway obstruction. In patients with acute respiratory distress syndrome, diagnosis reveals that their dyspnea cannot be explained by the above causes.

TREATMENT

Can the fluid in the lungs be drained in acute respiratory distress syndrome?

The fluid in the lungs (pulmonary edema) cannot currently be drained using medical technology. The only options are to facilitate its reabsorption back into the pulmonary blood vessels or to prevent further fluid leakage from these vessels.

For example, ventilators can be used (by increasing pressure to reduce fluid leakage), along with the appropriate application of hormones (to reduce leakage) and albumin.

Which department should be consulted for acute respiratory distress syndrome?

If the patient experiences severe difficulty breathing, it is recommended to call 120 for emergency assistance. In most cases, the patient will be sent to the emergency department for treatment, typically in the intensive care unit of the emergency or respiratory department.

Does acute respiratory distress syndrome require hospitalization?

If ARDS is suspected, hospitalization for observation and treatment is absolutely necessary.

What serious consequences can occur if acute respiratory distress syndrome is left untreated?

Without timely treatment, ARDS is often fatal. Statistics show that the mortality rate for hospitalized ARDS patients ranges from 30% to 70%. The primary causes of death are multiple organ dysfunction and respiratory failure.

What are the treatment methods for acute respiratory distress syndrome?

• First, the underlying disease must be treated to eliminate the cause;

• Ventilator therapy is a crucial treatment for ARDS;

• Other auxiliary treatments include the appropriate use of glucocorticoids, anticoagulation therapy, blood purification therapy, nutritional intervention, and extracorporeal membrane oxygenation (ECMO).

Due to the high mortality rate of ARDS, patients and their families must fully understand the condition. In most cases, invasive ventilator therapy, blood purification, and ECMO require signed informed consent from the family.

Does acute respiratory distress syndrome require endotracheal intubation?

Mild or early-stage ARDS may be treated with non-invasive ventilation (without intubation). However, if the condition does not improve or worsens due to infection, invasive ventilation should be considered, which requires endotracheal intubation or tracheostomy.

Compared to non-invasive ventilation, endotracheal intubation more effectively re-expands damaged lungs and improves gas exchange.

When is blood purification therapy needed for acute respiratory distress syndrome?

If ARDS is caused by an excessive immune response and a large number of inflammatory factors damaging the alveolar-capillary membrane (e.g., in severe acute pancreatitis), blood purification therapy (to filter inflammatory cells and cytokines from the blood) may be attempted.

However, since ARDS is often multifactorial, blood purification is not suitable for all cases.

When is extracorporeal membrane oxygenation (ECMO) needed for acute respiratory distress syndrome?

ECMO involves diverting blood from the lungs to an external device, where it is processed (removing carbon dioxide and adding oxygen) before being returned to the body to nourish organs.

Due to its high cost, ECMO is not widely available. It is only used in qualified medical institutions for ARDS patients who do not respond to conventional treatment and whose underlying condition is reversible.

Does acute respiratory distress syndrome require surgery?

If ARDS is caused by a clear infection (e.g., abscess) or necrotic lesion (e.g., severe necrotizing pancreatitis), doctors may consider surgical removal of the infected or necrotic tissue to reduce damage to the alveolar-capillary membrane and alleviate ARDS, depending on the risks and benefits.

Can acute respiratory distress syndrome recur?

If the alveolar-capillary membrane is damaged again, ARDS can recur. Thus, a patient may experience multiple episodes in their lifetime, though most recurrences are not directly related to the initial episode.

DIET & LIFESTYLE

What is suitable for patients with acute respiratory distress syndrome to eat?

For mild cases using non-invasive ventilators, soft, easily digestible, and non-greasy foods are recommended if the patient can eat.

Severe cases requiring invasive ventilators with intubation typically cannot eat independently. Doctors will prescribe nasogastric tube feeding (delivering liquid nutrition directly to the stomach) or intravenous nutrients to ensure adequate energy intake.

What should family members of acute respiratory distress syndrome patients pay attention to?

If the patient exhibits symptoms like difficulty breathing, coughing, or fever—indicating possible infection—family members should wear masks when in contact and seek medical attention promptly to prevent worsening or spread.

If the patient appears weak, sweaty, or has cold, clammy extremities, call emergency services (120) immediately.

PREVENTION

How to Prevent Acute Respiratory Distress Syndrome?

• Take precautions during autumn and winter. Some patients may initially present with only respiratory infections, such as coughing or fever. If symptoms persist or worsen despite symptomatic treatment, seek medical attention promptly for re-examination.

• Patients and their families should remain vigilant. Difficulty breathing (respiratory distress) is generally a warning sign. Early medical intervention can reduce the likelihood of progression to ARDS.

• Some cases of ARDS caused by extrapulmonary factors may occur in hospital settings. If patients experience difficulty breathing, shortness of breath, dizziness, or chest tightness, they should notify medical staff immediately.

• Parents must supervise their children closely to prevent accidents such as drowning, accidental injuries, or lung contusions.