Respiratory failure is the primary symptom of critically ill patients affected by the COVID-19.
Let’s figure out more about the complications of this new coronavirus. The more we know, the better we are able to protect ourselves from this threat.
The Initial Symptoms
The initial symptoms of the COVID-19 are shortness of breath and difficulty in breathing, which may eventually lead to pneumonia.
The virus replicates, spreads to the respiratory tract, and starts to damage lung cells.
At this point, the immune system starts to defend our body, like an army against its enemy. However, our body is not ready to fight and starts a generic attack, like an army that does not know what it is up against.
Inflammation: White blood cells engage with all kinds of common weapons, ready to fight; they facilitate the arrival of incoming troops, the highways (blood vessels) widen to make room for trucks full of soldiers, and the battle begins.
On the battlefield, i.e. the lung, the troops gradually fall. The white blood cells are replaced by other white blood cells; more troops arrive. Bit by bit, material accumulates in the spaces between the lung cells which are dedicated to processing oxygen and other respiratory gases.
Essentially, the same thing happens when we get a bruise on our arm: IT SWELLS FOR 15 DAYS!
Let’s try to explain this with the help of some images.
The image below shows normally aerated lungs where the inhaled air is colored in dark grey.
The image below is taken from a patient affected with pneumonia caused by the COVID-19. The grey area in the lungs is very small because it is replaced by inflammatory cells, debris, etc. that “compact” the lungs (colored in white). Air intake and circulation are compromised, so the patient cannot get enough oxygen.
What is happening here? The amount of oxygen going into the lungs is not enough, thus the patient feels a sense of “hunger for air” and cannot breathe properly.
Moreover, compared to other patients with pneumonia, people affected by the COVID-19 display respiratory muscle fatigue later than the typical patient with adult respiratory distress syndrome (ARDS) and low compliance. This aspect gives a false sense of reassurance, and it can subtly progress towards a drastic and unexpected deterioration characterized by severe dyspnea at rest (1).
It seems that these patients, compared to others affected by common pneumonia, have an increased tendency to lower oxygen levels in the blood which can cause fainting (1).
Critically ill patients are treated in intensive care units.
Some critical patients can benefit from non-invasive ventilation like helmet-based ventilation or face masks connected to a ventilator that helps the patient push air into the lungs while breathing. However, this type of ventilation is not recommended for patients with pneumonia caused by the COVID-19 because:
- Many patients must subsequently undergo invasive mechanical ventilation;
- During non-invasive ventilation, the air (and therefore the virus) exits the patient and can infect others;
- The patient needs to use a ventilator that cannot be used for other patients.
Invasive (mechanical) ventilation
The most effective treatment for critical patients with acute respiratory failure caused by the COVID-19 is mechanical ventilation. The lungs become full of debris and “stiff”, so non-invasive ventilation is not effective. Mechanical ventilation on the other hand, ensures adequate oxygenation while waiting for the reduction of the inflammation and infection.
It seems that early mechanical ventilation is more effective at ensuring tissue oxygenation, and is somehow linked to a better potential outcome.
If mechanical ventilation is not sufficient, sometimes the extracorporeal membrane oxygenation (ECMO) machine is used. This is connected to the patient through plastic tubes and pumps blood from the patient’s body to an artificial lung that adds oxygen to it. The ECMO machine then sends the blood back to the patient’s body via a pump. This type of treatment is only available in intensive therapy.
How many beds for critically ill patients would be needed? Read the day-to-day forecasts: It’s time to react!
Marco De Nardin, M.D., Anesthesiologist, and Critical Care Doctor