How does being on a ventilator cause someone on it to have organ damage? I thought ventilators are just supposed to help you breathe?


How does being on a ventilator cause someone on it to have organ damage? I thought ventilators are just supposed to help you breathe?

In: Biology

Ventilators are designed to force air into the lungs to allow you to breathe. As such, a foreign object is inserted into your throat which your body may reject.

Your body is also designed with several steps to prevent foreign objects from reaching your internal organs. Having a hose pushed into your lungs bypasses several of those defensive measures, potentially opening up a clear route for infectious diseases.

A third possibility is that the hose is inserted improperly or too forcefully resulting in trauma to the tissues. If you’re admitted to a hospital and are in need of a ventilator, it’s likely that you’re body has been weakened by a disease. As such, a normal insertion may prove to be too forceful for you.

Your body really doesn’t like things in your wind pipe, which is where the ventilator goes. This leads to an inflammatory response – your body’s immune system fighting back. Drugs are administered to keep this inflammation somewhat in check, but your wind pipe and lungs still suffer.

Doctors believe this is the cause of some kind of sepsis, a serious infection, that spreads to other organs, leading to multiple organ failure

I think I’m going to struggle with answering your question directly but I’ll try and clear some stuff up.

There are roughly 2 types of people who are ventilated. The 1st are people who won’t breathe on their own (head injury, drug intoxication) and the 2nd are people who you choose to take over their breathing (lung damage and lots of others).

The first group are easy in the way, you can place a breathing tube and connect them to a ventilator.

If I tried to do that to someone awake, it would be a disaster. In order to allow this to happen, you have to give drugs to reduce their consciousness, their pain and their ability to move/cough. These drugs will do damage over enough time even to healthy individuals.

In the case of covid, there are already lots of reasons why they may be in multi organ failure. Sepsis or septic shock reduces blood flow through the organ. Blood clots do the same for different reasons.

There is still a lot more to write about this but I think the important part is that putting someone on a ventilator is risky and precarious. It is usually only done if there is little other option.

As a side note, lots of people are ventilated under general anaesthetic but the vast vast majority of these people are not critically ill and therefore it is very different.

Ventilators force a certain quantity of air into your lungs (tidal volume). In healthy lungs, as long as the tidal volume isn’t too high, then the air distributes itself pretty evenly throughout the lungs. You can also use quite low pressures to push the air in. A coma patient with healthy lungs may be fine on a ventilator for a very long time.

However when sick, some areas of the lungs may become gummed up with mucus or inflamed – when this happens the air doesn’t flow as easily into these areas. This can cause the remaining healthy areas to get stretched since the air forced in flows preferentially to these healthier areas. This causes damage over time. In addition you may have to increase the inflation pressure to try and push the required volume of air in, which has a similar damaging effect.

It’s a balancing act, you can generally turn up oxygen to help get more oxygen into the blood if a patient is struggling – however its difficult to turn up the rate that carbon dioxide leaves the blood. You can either increase the tidal volume, or increase the breathing rate – however a faster breathing rate means that there is less time for carbon dioxide and oxygen to diffuse out and you may need to use higher pressure. At some point the patient can become so ill that you simply have to turn up the tidal volume to stop carbon dioxide buildup, and this can cause damage.

When a healthy person takes a breath, air is pulled into the lungs (negative pressure). Your body grows and functions based on that negative pressure in your chest. It affects not only your lung function, but also has significant impact on your heart and circulation.

Ventilators are designed to PUSH air into the lungs (positive pressure). This switch changes the way your lungs accept and release oxygen and carbon dioxide. But positive pressure also puts unnatural strain on your heart and circulation. This can lead to heart failure. An impaired circulatory system (heart, arteries, veins, etc.) has trouble keeping blood pressure from going to high or too low. Blood pressure that is too high or too low can very quickly and very seriously injure any (or all) major organs in the body.

In addition to positive pressure-related complications, bed rest (required for ventilators) can lead to overall physical deterioration. Medications required to maintain patient safety and comfort while on a ventilator can stress organs. Also, whatever got them sick or injured enough to need the ventilator in the first place can contribute to multiple organ failure.

Also, the more pressure the ventilator uses to push air into your lungs, the harder it is on your lungs and heart. So if a patient has very sick “stiff” lungs and needs a lot of pressure to breathe, they are much more likely to suffer complications worse and sooner than someone who can breathe with less pressure.