Hand drawn Science Popularization: why is the new coronavirus fatal? What are the treatment principles?

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 Hand drawn Science Popularization: why is the new coronavirus fatal? What are the treatment principles?


Specifically, six of the 41 new coronavirus infections in the early stages of the outbreak died of ARDS.

The new coronavirus is the pathogen, the so-called new coronavirus pneumonia is a disease, and ARDS is a clinical symptom.

How does ARDS kill these severe patients? What is the current treatment for these severe patients? We refer to the papers in the New England Journal of medicine, an authoritative medical journal, to help you better understand the new coronavirus by means of comparison, hand drawing and other easier ways.

1u3001 Lethal principle:

We can think of the lung as a tree. Trees have trunks, branches, branches and leaves. Lungs also have trachea, bronchi and alveoli. In the tree, the leaves carry out photosynthesis and transmit nutrition back to the whole tree; in the lung, air passes through the trachea at all levels, and finally oxygen enters the blood through the alveoli. As shown in the picture:

The normal working alveoli are shown in the figure. Note the green part. Oxygen diffuses into the blood vessels through the respiratory membrane

The so-called new coronavirus pneumonia is the pneumonia caused by the infection of new coronavirus. If your hand gets caught in the door, it will swell soon. This is also an inflammation, which is essentially a large amount of protein rich liquid oozing into tissue space.

Schematic diagram:

For severe patients with new coronavirus infection, their entire lungs are full of inflammation, most of the hundreds of millions of alveoli are blocked, making the human body very hypoxic and unable to breathe. In severe cases, respiratory failure and ARDS will occur.

The above is the working principle of ARDS, that is, the severe lethal principle of new coronavirus. Including the coronavirus behind SARS, some influenza viruses, respiratory syncytial viruses, etc., will cause ARDS.

At present, for severe patients with ARDS, the only way is to support the treatment, there is no pharmacological targeted measures (a few have been initially proved effective, but failed to pass the clinical drugs).

The only way to support treatment is to go to intensive care unit (ICU) and use ventilator.

2u3001 Principles of treatment

As we mentioned just now, severe patients with ARDS cannot breathe by themselves. Their lung failure, such as the bodys own anti-inflammatory, often has died. There is no way to speed up or slow down the process of self inflammation.

The purpose of entering the ICU and getting on the ventilator is to forcibly maintain the patients breath through mechanical ventilation. In essence, it is to race with the virus with the help of the power of the machine, and maintain the life of the patient before the inflammation disappears by itself, so it is called supportive treatment.

Since the beginning of this century, there have been several major innovations in ventilator support therapy for ARDS.

1) Low tidal volume ventilation

People without knowledge of pulmonary medicine may think that the best way is to let the ventilator blow in a lot. In fact, it is not.

A breath, a breath, a tide. Clinicians found that because the alveoli were blocked and smaller than when they were healthy, the conventional tidal volume would lead to more serious swelling u2192 collapse u2192 swelling u2192 collapse of alveoli, which made the inflammation worse. As shown in the picture:

Therefore, in 2000, experts invented the low tidal volume ventilation, which sounds anti logical. In short, lower tidal volume (with higher frequency) is used to reduce the pressure exerted by the ventilator on the alveoli, as shown in the following figure:

Low tidal volume ventilation proved to be extremely effective, reducing the mortality rate of ARDS patients from 39.8% to 31% - provided that there are enough medical resources for patients to enter the ICU and plug in the ventilator.

2) Anesthesia Technology

Experts further found that patients would not be comfortable with low tidal volume ventilation. Because these patients with their own respiratory distress, will subconsciously increase the intensity of breathing, disturbing the role of the ventilator.

Therefore, doctors adjusted the anesthesia techniques, kept very detailed medical observation for different patients, and adjusted the dosage, so as to keep the patients respiratory rate and ventilator synchronized. This technique also proved effective, reducing the mortality rate from 40.7% to 30.6%.

This method has a great demand for medical human resources. There must be enough respiratory doctors, anesthesiologists and paramedics to keep the observation of patients physical signs at all times, so as to adjust. However, these conditions are often difficult to meet in an outbreak.

3) Prone ventilation

In bed, most of the patients we see are lying down. However, if patients use the ventilator in lying position, some alveoli will collapse more seriously than others due to gravity, pulmonary edema and many other factors.

Experts further found that when using the prone position (that is, lying on the stomach), the alveoli are under less pressure in all aspects, which is more conducive to recovery. Finally, the mortality of ARDS patients treated with prone posture was reduced from 32.8% to 16%.

However, as mentioned above, the outbreak has led to a serious shortage of medical resources, making it difficult for the vast majority of people infected with the new coronavirus to get beds, let alone enter the ICU and enjoy the great help brought by these innovations. With the completion of two new centralized hospitals, huoshenshan and leishenshan, as well as the new centralized hospitals outside Hubei, this situation will be greatly improved. At least for the severe patients, as long as they can enter the ICU, plug in the ventilator, as long as they can get the care of the respiratory doctors, anesthesiologists and paramedics, it is believed that the vast majority of patients can be recovered. Source: pingwest, editor in charge: Qiao JunJing, nbj11279

However, as mentioned above, the outbreak has led to a serious shortage of medical resources, making it difficult for the vast majority of people infected with the new coronavirus to get beds, let alone enter the ICU and enjoy the great help brought by these innovations.

With the completion of two new centralized hospitals, huoshenshan and leishenshan, as well as the new centralized hospitals outside Hubei, this situation will be greatly improved. At least for the severe patients, as long as they can enter the ICU, plug in the ventilator, as long as they can get the care of the respiratory doctors, anesthesiologists and paramedics, it is believed that the vast majority of patients can be recovered.