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Current time:0:00Total duration:7:12

Video transcript

well we talked about cyanotic heart diseases we'll come back to what cyanotic means in just a second so congenital means that it is something that the person was born with so they have heart disease not because they didn't eat right or something was wrong with their environment but because their heart is structurally abnormal and these days since without the technology we can actually ultrasound the moms belly and see that this baby has congenital heart disease because it's again it's something structural that we can physically see with our eyes for cyanotic I think the best synonym to use is blue so blue in medical terms this means this child this baby looks blue and by the way I'm going to keep saying baby because when we think of congenital heart disease we're usually talking about babies because they need treatment early and yes they do survive into adulthood which is nice but when we talk about treatment or diagnosing most of the time we're dealing in the pediatric world so this baby is blue now babies can look blue for lots and lots of reasons it could be a lung disease thing it could be something with their circulation but obviously for our purposes we care about their heart making them blue so this is a baby the most obvious ways to see this bluish tint in people of all colors are the mucous membranes so the whites of their eyes might turn blue their lips and the tip of their tongue is a good place sometimes if it's really severe their body will start to become cyanotic and that's how you know they really are lacking oxygen so to go back even further we have this idea in medicine that when blood has a lot of carbon dioxide in it it is blue and blood with oxygen in it is red how we usually think of blood and this is true to a certain extent blood that has less oxygen and it has a darker tint but it's not actually blue if our purposes will keep it that way so I just want to go over the the function of the heart really quickly this is not going to be anatomically correct this is my schematic of a heart and we have our four chambers just want to go over roughly what the heart does so this is the top two are the atria so this is the right atrium oh the other thing is this is going to be right and this is going to be left that's just how it's designated in medicine because when we look at an x-ray or a film is usually flipped like this so let's get used to the right side being on the left side so the right atrium left atrium the right ventricle these bottom chambers are going to be ventricles they're the big pumping chambers and the left ventricle so blood from the body that's been used up by the tissues the oxygens being used up it's going to be a bluish blood we think of it as deoxygenated blood blood with a lot of carbon dioxide or co2 in it this gets returned to the right atrium first from there it goes through the right ventricle there's going to be a valve here actually they're going to be valves between each of the chambers and places and those are some of the places that can be structurally abnormal in congenital heart disease but we'll worry about that in just a second from the right ventricle that gets pumped to the lungs and the lungs is where we pick up oxygen that's why we breathe in and out giving oxygen into our blood so blood coming out of the lungs then is going to be red because oxygen has been added to it so red blood returns to the left atrium have you noticed that the atria seem to receive blood from outside the heart these are the receiving chambers so it flows into the left ventricle the left ventricle is the most powerful one because it has to pump blood really far to the rest of the body so now we have this person that's red because they have more oxygen in their blood and just for completeness sake vessels that receive blood from the heart are called arteries so we have red blood usually traveling in the arteries delivers it to the tissue oxygen leaves to go work in the tissues and then once the oxygen is extracted the blood goes into veins and veins are vessels that return blood to the heart so usually in a healthy person we want the oxygen content in arteries to be about above 90% for a healthy person is actually usually around 98 to 99 but above 90% we can live with we like that so now the oxygen in the veins will obviously be less than any percent we're probably happy with 70s 80s it depends on a lot of different factors so you see that when we think of arteries and veins we expect them to have different levels of oxygen so what is cyanosis then I said before that this blueness comes from the blood not having enough oxygen and here we're talking about arteries vein oxygen content yeah we care in some circumstances but right now for congenital heart disease we care about artery saturation of oxygen so what exactly we have cyanosis kind of is a little bit dependent on the person but we know for sure that it is less than 90 percent so I'm going to say cyanosis starts to happen around eighty to eighty-five percent oxygen it's a nice ballpark you might go up and down depending on if this person is anemic how well their lungs are working all these things vary but in general cyanosis tells us we're definitely less than ninety percent and we're somewhere in the 80s ballpark if we drop below that it starts to be very dangerous so people can live in the 80s if we drop much lower than this it starts to get dangerous and life-threatening people can live in the 80s for the saturation of oxygen it's not ideal but they can definitely live here for some congenital heart diseases getting them to the 80s is kind of our the best we can do we don't use cyanotic a disease as kind of a clinical way to assess them it's more of a category that separates cyanotic from non cyanotic heart disease there are heart diseases that you can have structural abnormalities where even though your heart doesn't have great function your artery oxygen saturation doesn't get affected this baby will stay nice and pink above 90% so this is really a category that we're talking about cyanotic versus non cyanotic without going into too much detail if we just look at this rough diagram of the heart cyanotic diseases is a general rule will involve some so of mechanism for the blood to be mixing in a way that the right is shunting to the left shunting talks about something that was supposed to be over here being pushed over there so as you can see the right side of the heart is this blue blood when it gets pushed over here then we mix and we drop the oxygen saturation over here so just in the back of your mind think about right and left shunting and how the blood is mixing this way when we talk about specific cyanotic heart diseases