How Coronavirus Kills — “ARDS” and its treatment.
There is a lot of question about how does the corona virus actually kill people . A large percent of the people who test positive and die are on ventilators and they died with something called a ARDS.
ARDS is how the corona virus kills it’s not just the corona virus but many other viruses including the influenza virus that we have every year. How is it that this happens it’s through acute respiratory distress syndrome.
Lets learn how that happens. So you first have to understand lung Anatomy and to understand that lets build an analogy.
We all know a tree. So the tree has a tree stump and then it branches and then those branches branch and then further those branches branch until finally you get to the leaves and these leaves capture the sun’s rays and that’s what gives you photosynthesis and that’s how the tree lives.
So what happens is that this tree and the branches increase the surface area of the leaves on the tree so that if you were to pluck off all of the leaves and you were to put them on the ground next to each other, the surface area that is represented by those leaves would be larger than the shadow that is produced by the Sun on that tree.
Well it’s the same exact thing that happens with your lungs you’ve got an airway and then that airway divides into a right mainstem bronchus and into a left mainstem bronchus and then you have a right upper lobe you have a right middle lobe right lower lobe left upper lobe and you have a left lower lobe and then these things of course divide into much smaller branches and instead of leaves at the end of all of these things what you have is something called an alveoli which is a tiny little small grape like structure that the air gets into.
The air of course has oxygen and as shown in the diagram, this is how alveolus looks like on a large scale. How many alveoli are there in the human body well there’s about 600 million of them. These are very very small.
So what happens is deoxygenated blood comes by and its job is to pick up the oxygen that comes in to the alveoli and then when that oxygen comes in it oxygenates the blood and then that blood goes back to the heart and then to the body and all your muscles that’s how you get oxygen and so you can imagine that this is very very thin because the oxygen which comes down here has to diffuse into the bloodstream.
So far so good but what happens well just like when you hit your finger in the door your finger swells that’s because there’s inflammation occurring where you hit your finger in the door and inflammation causes a leakage of fluids into the tissue space.
Similarly what happens here is that you get a viral infection the virus affects your lungs and with ARDS the entire lung becomes inflamed not just in one area like you would have with a pneumonia or one particular area for instance on your finger and it would just stay in one particular finger in your whole hand wouldn’t swell no.
With ARDS the entire lung goes crazy with inflammation and so what happens air instead of having a nice thin area inflammation goes everywhere and you get
- A large barrier
- A fluid that goes into the interstitial space
- Furthermore these capillaries start to become leaky and fluid starts to leak into the alveolar space as well and this starts to fill up with liquid proteinaceous liquid that prevents oxygen from getting into the bloodstream.
So instead of having nice oxygenated blood this blood becomes hypoxic and you become hypoxic if you have ARDS and you have a hard time breathing and that’s when you get placed on the ventilator there’s really nothing you can do to speed this up.
There’s nothing that you can do to slow it down.
You have to be supported on the ventilator so that you’re getting enough oxygen and that the Machine can breathe for you until just like everything else after you hit your finger in the door and the swelling goes away this fluid will eventually go away as well the key though is keeping you supported during that period of time until the fluid goes away and then once again the oxygen will be able to go back into the system and you will get oxygen back to your tissues.
So here’s another look at that we get oxygen that’s going down into these criminal structures called the alveoli. They go in to these alveoli and they cause deoxygenated blood to turn into oxygenated blood and then go back to the heart.
Three things that have been learnt in the last decades to address ARDS that can improve survival in these patients who are on ventilators to help them beat coronavirus or for that matter any other virus whether it be influenza whether it be respiratory syncytial virus any other kind of virus for beating and getting better.
If you have ARDS and you’re on the ventilator so the first thing that look at is what they noticed back in and actually before is that when we put people on the ventilator and the ventilator puts a breath into their Airways what we were trying to do is we were trying to make sure that we were ventilating patients well. And that’s important in some situations because the blood that is poor in oxygen also has carbon dioxide which is given up from the muscles. Well this carbon dioxide would need to be ventilated to be taken out on exhalation so that it would be coming out well. In order to do that we got to make sure that enough volume of air was going back and forth back and forth the problem with that though is that we were inflating these alveoli and then when we were releasing the pressure and letting the air out these alveoli would collapse down and nothing was keeping them open. So they would be opening and closing opening and closing shutting and opening. So that was causing a lot of shear stress and of course what’s the whole problem here that we’ve got inflammation which is what’s causing the whole problem here in the first place and that’s causing these membranes to become very thick and the oxygen can’t get in there.
So by ventilating these patients with large tidal volumes we were causing the inflammation to actually get worse than it would have been if we hadn’t done that. So the scientists started to look at this and say wait a minute what happens if we just put a lot of pressure down here to keep these alveoli open and only use a small amount of tidal volume to ventilate these patients and yes we won’t be able to get as much carbon dioxide out of them but we don’t really care so long as we’re not adding more inflammation to it.
- So that first thing that we looked at this is back in the earlys that is came out is low tidal volume and that would almost certainly cause the PCO or the partial pressure of carbon dioxide in the blood to go up. So this was called a low tidal volume strategy and sure enough paper was published in in the New England Journal of Medicine that showed that we could affect change and we could decrease the mortality at the time from 40 percent down to about 31 percent mortality. So that was a huge drop in mortality and all we did was we just ventilated people differently using low tidal volume.
- Now when you’re ventilating people with low tidal volume it’s not very comfortable. They’re trying to breathe more because they don’t like that increased carbon dioxide levels and so they would try to breathe over the ventilator and it would try to breathe differently than what the ventilator was telling them to do. And in these cases they would usually sedate the patients but if they sedated them too much bad things could happen to them. They could get blood clots , their blood pressure would go down. So the second thing that they came up with was actually paralyzing these patients using medications so that they were in perfect sync with the ventilators and so that was paralysis. Paralysis requires pretty intensive care in the intensive care unit. You need good ancillary services, you need good respiratory therapists, you need good nursing something that you might not get if there’s a huge outbreak but you could get if attention was made to this. So they were able to drop the mortality from 41 % down to 32 %.
- What they also started to realize is that patients in the hospital for whatever particular reason if you ever look at them in bed they’re on their back and what they decided to do was flip them over. There was a number of reasons for this so that their belly was down and that their back was up. We call this prone positioning and if you do this for about 17–18 hours a day you can actually decrease the mortality they found from 33 % down to 16 % .
Thus we can see there are three breakthroughs in treatment of ARDS the final commonpathway for morbidity and mortality in the coronavirus that we’re talking about.
But the other thing about this that’s interesting is we can do a lot if we catch it early and we get people into the hospital and we get them in the intensive care unit and we get them on ventilators and we’re able to appropriately treat them with good quality medical care.
Three things that really make a difference then we’ve got a good chance so that they’re not another statistic of mortality but they survive this.
So really the purpose of putting these updates on is to make sure that people understand the medical background of what’s going on.
Sometimes these stories about how outbrakes can be very scary and for good reason but we need to understand medically what it is that’s going on because knowledge is power .