Acute respiratory failure

There are several causes of “Acute Respiratory Distress Syndrome” – ARDS for short. Examples include pneumonia and blood poisoning, but also the inhalation of smoke, toxic fumes or water. Acute lung failure can be recognized by symptoms such as shortness of breath, rapid breathing, an accelerated heartbeat and a blue discoloration of the skin due to the lack of oxygen. Doctors have to give artificial respiration to many patients with ARDS in order to save their lives.

What is acute respiratory failure?

Acute respiratory failure is a life-threatening condition and always a case for intensive care. The lungs are so severely damaged that fluid accumulates there and their function deteriorates considerably. As a result, organs and tissues no longer receive enough oxygen and nutrients. Without immediate treatment, acute respiratory failure is often fatal. The lung disease has many other names: Acute respiratory distress syndrome, shock lung, adult respiratory distress syndrome or in English “Acute Respiratory Distress Syndrome”, abbreviated ARDS.

The causes of acute respiratory failure can be diseases such as pneumonia. However, inhalation of smoke and toxic gases as well as injuries to the lungs caused by an accident are also possible causes. The symptoms of ARDS are shortness of breath, rapid breathing and an accelerated heartbeat. Patients feel increasingly exhausted and their skin turns bluish. Eventually, the respiratory distress becomes more and more severe until artificial respiration is often necessary. It ensures the oxygen supply and improves the chances of survival.

Doctors always treat the cause of the acute respiratory failure, for example pneumonia. In addition, there are other supportive therapies, such as painkillers, circulation-stabilizing medication or blood thinners. Despite intensive treatment, ARDS is associated with a high mortality rate.

Acute respiratory failure – frequency and age

Worldwide, the incidence of acute respiratory failure is between 13 and 69 per 100,000 inhabitants per year – depending on the literature and studies. Around seven percent of all patients treated by doctors in intensive care units develop ARDS. This figure increases to 12.5 percent if patients remain in the intensive care unit for longer than 24 hours.

In principle, acute respiratory failure can affect people of any age: Newborns, children, adolescents, adults and the elderly. In older people, diseases are often the cause of ARDS.

Acute respiratory failure: causes and risk factors

Acute respiratory failure can have various causes. The causes may lie in direct damage to the lungs themselves, but also outside this organ. What they all have in common is that acute inflammatory processes damage the lungs.

Acute respiratory failure: progression in stages

The process of acute respiratory failure can be described using various stages and processes:

• More fluid enters the lungs from the blood vessels and pulmonary edema develops. The air sacs (alveoli) and their protective film are particularly affected.
• Inflammatory messengers and immune cells accumulate in the lungs. The inflammation causes the connective tissue in the lungs to multiply – resulting in fibrosis. This makes it harder for the lungs to expand and they are no longer sufficiently ventilated.
• The alveoli collapse during exhalation and normal gas exchange in the lungs and oxygen supply to the body are no longer possible.

Causes inside and outside the lungs

The following causes, among others, can trigger Acute Respiratory Distress Syndrome:

• Pneumonia – caused by bacteria, viruses and other pathogens, this lung disease is the most common cause of ARDS.
• Blood poisoning (sepsis)
• Embolism, e.g. fat or amniotic fluid embolism
• Inhalation of stomach contents or water (near drowning)
• Severe injuries to the lungs (lung trauma), e.g. lung contusion due to an accident
• Acute, severe inflammation of the pancreas (pancreatitis)
• Inhalation of smoke, chemicals or toxic gases
• Infections outside the lungs
• Polytrauma: At least one life-threatening injury or several injuries that are life-threatening in combination.
• Burns
• Shock
• Many blood transfusions
• Drug overdose

Smoking (depending on the dose) and chronic alcohol abuse may also be risk factors for ARDS.

Symptoms: Acute respiratory failure causes shortness of breath

The symptoms of ARDS usually set in within a week of the trigger or causative event. Acute respiratory failure progresses in several phases, each of which is associated with different symptoms:

• Shortness of breath, accelerated breathing
• Fast heartbeat
• Restlessness
• Increasing exhaustion – breathing becomes increasingly difficult
• Blue coloration of the skin (cyanosis of the fingers, lips) due to lack of oxygen
• Pronounced shortness of breath
• Rales in the lungs
• Respiratory failure – ventilation is necessary

Doctors differentiate between three degrees of severity in ARDS – depending on the extent of the oxygen deficiency: mild, moderate and severe. The choice of treatment and the chances of survival depend on this.

Acute respiratory failure: diagnosis with us

Acute respiratory failure is an emergency that we need to recognize and treat quickly. Otherwise the prognosis is unfavorable. When diagnosing ARDS, we start by taking a medical history. The type, intensity and location of the symptoms are important, but also when the symptoms first started. Existing illnesses (e.g. pneumonia), triggering events such as an accident (e.g. inhalation of gases), injuries to the lungs or the use of drugs also play a role.

Acute respiratory failure – examinations for diagnosis

This is followed by a physical examination, during which we listen to the heart and lungs with a stethoscope. Unusual noises when breathing or disturbances in cardiac activity can be detected in this way. We also palpate the lungs. Further clues are provided by existing symptoms such as a blue coloration of the skin, shortness of breath, accelerated breathing, rapid heartbeat, restlessness or confusion.

This is usually followed by further examinations. The most important are:

• Blood test: Determination of the inflammation values C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and leukocytes as well as other blood values.
• X-ray examination – Shows the extent of the lung changes and is used to assess the success of the treatment.
• Sputum analysis: examination of sputum in the laboratory, e.g. for bacteria, viruses, fungi
• Blood gas analysis: We determine how well the body is supplied with oxygen. The blood gases oxygen and carbon dioxide provide indications of this.
• Ultrasound examination (sonography)
• Computed tomography (CT): Used to visualize the lung tissue. It is an important tool for recognizing the type of lung changes and differentiating them from other diseases.
• Echocardiography (cardiac ultrasound) to rule out pulmonary edema due to heart disease.
• Right heart catheter to differentiate between ARDS and cardiac pulmonary edema.

Acute respiratory failure – diagnostic criteria

We diagnose ARDS on the basis of various criteria, for example if:

• the symptoms have started acutely, for example within a week of exposure to the trigger or event,
• the respiratory symptoms have rapidly worsened,
• fluid in the lungs (pulmonary edema) is visible on an X-ray,
• respiratory failure occurs for no known reason, such as heart failure or
• a lack of oxygen (hypoxemia) can be detected in the blood.

Acute respiratory failure: prevention, early detection, prognosis

There are no special measures for the prevention and early detection of acute respiratory failure. The general rule is therefore: always see your doctor promptly if you have respiratory problems and other complaints.

In addition, always have existing illnesses such as pneumonia treated promptly and adequately. And if you have had an accident in everyday life, at home or at work, for example with toxic fumes, gases or chemicals, you will also need to see a doctor. Otherwise, you should always take adequate protective measures when handling them.

Course and prognosis of acute respiratory failure

The course and prognosis of acute respiratory failure are not generally predictable. How severe the ARDS is and whether doctors diagnose and treat it quickly plays a role. In many cases, however, the prognosis is unfavorable and those affected do not survive the acute lung failure. ARDS can cause multi-organ failure and ultimately death. The mortality rate for people with ARDS is between 27 and 45 percent.

The highest risk of death from acute respiratory failure is for older people and people who have other underlying illnesses, such as cardiovascular disease. In contrast, young people whose acute respiratory failure is the result of an injury have the best chance of making a full recovery within the next six to twelve months.

Acute respiratory failure: treatment usually involves ventilation

In the case of acute respiratory failure, it is important that treatment begins quickly. To date, there are no drugs with which we can treat ARDS. It is important to eliminate the cause of the disease or the trigger. We treat patients with acute respiratory failure in the intensive care unit. There we closely monitor all vital functions and check your state of health.