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Current time:0:00Total duration:11:17

Video transcript

obstructive shock is very similar to cardiogenic shock and that's actually why I have this heart drawn out right here in cardiogenic shock the problem is the heart is not able to squeeze properly and pump blood forward an obstructive shock it's actually very similar except the issue here is it's an obstruction there's an obstruction either surrounding the heart or in the blood vessels that prevents blood from being pumped forward but because it's very similar you can actually have very similar symptoms as you see in cardiogenic shock for example an obstruction can cause blood to back up into the lungs and into the right side of the heart and of course blood in the lungs can cause coughing and difficulty breathing due to all this accumulation of fluid in the lungs it's known as pulmonary edema as blood continues to back up as we are showing this fluid overload can cause an enlarged heart cardiomegaly fluid continues to back up into the system you might see something called jvd jugular venous distention as blood backs up into the neck and if it's severe enough blood can back up and cause global swelling throughout the body this total swelling throughout the body is known as Ana Sarka so pulmonary edema cardiomegaly jugular venous distention and Ana Sarka total body swelling can all result from obstructive as well as cardiogenic shock it's all signs of just fluid overload add in such signs as increased heart rate tachycardia and decreased blood pressure from the inability of blood to be pushed out of the heart this hypotension and of course decreased oxygen delivery to the system so what can cause obstructive shock well for that let's go ahead and take a look down here here I've got four different hearts drawn out so that we can go over different types of obstruction the first type I want to go over is called cardiac tamponade cardiac tamponade is pressure created around the heart because of accumulation of fluid or blood in the pericardial sac and what the heck's the pericardial sac well it's actually a sac that the heart sits in that is lined with cells that produce a fluid that helps keep the heart frictionless as it beats because your hearts going to be beating your whole life so putting in this pericardial sac with on an oil like fluid allows for this decrease friction now the issue with pericardial tamponade is an over accumulation of fluid this is known as a pericardial effusion this effusion might occur for example let's say there's a tear in the ventricular wall of the heart blood is going to start pouring out and as it starts pouring out it just fills up the pericardial sac and as the fluid continues to accumulate it puts pressure on the heart because there's this fluid surrounding the heart the heart can no longer expand and so what you see is this area these compartments of the heart end up becoming smaller because the heart is just so constricted so when the heart does squeeze it can't push that much blood out because there's not enough blood that can get into the heart and also because of this increased pressure surrounding the heart if blood is trying to get back from the venous system into the inferior vena cava or the superior vena cava trying to get back into the right atrium not only is the compartment smaller but because there's such a high pressure around the heart the blood can't even get in there remember that fluids and gases tend to go towards lower pressure and that's exactly how the heart functions when it squeezes pressure increases in the heart to push blood out but now the trouble is there's too much pressure around the heart so blood can never even get in through the blood vessels into the heart so you have decreased venous return into the heart along with decreased compartment size so the ventricles and atria are decreased in size which decreases the amount of blood that can be pushed out of the heart the stroke volume now cardiac tamponade the fluid accumulation around the heart is just one example that involves this pericardial sac another example is constrictive pericarditis constrictive pericarditis is when the pericardium gets very rigid so rather than blood accumulating around the heart the pericardium is putting the pressure directly on the heart so the pericardium might become constricted because of infection a lot of scarring occurs something like that but you get the same concept blood cannot be pushed out of the heart another example of obstructive shock is a tension pneumothorax what's a tension pneumothorax tension pneumothorax is when you have air that leaks into the pleural cavity what's the pleural cavity pleural cavity is a space that includes your lungs and the heart and this space is bordered by the diaphragm the chest walls which I've drawn on the lateral sides and soft tissue and other things on the topside now this is really an oversimplification of the pleural space but I just want to give you an idea that it's really an enclosed space and the concept here is you again have an increase of pressure but this time it's not just surrounding the heart it occurs in the pleural space as well so for example let's imagine a patient has a stab wound let's say got into a fight with somebody with a knife and they stabbed him now let's say the chest wall acts as a one-way valve and air is able to get into the pleural space but it cannot escape with each deep breath that the patient takes not only are they drawing air into the lungs through their trachea but also air is getting pulled into the space around their lungs this causes all the organs to shift over away from this air in the pleural cavity also known as the thoracic cavity so this is a pneumothorax air in the thoracic cavity and it's causing all this tension as it pushes all the organs to the side including the lungs the heart and the trachea so this causes constriction on the heart and just like we saw before over here blood can't get into the heart because there's a higher pressure and so blood is not able to really break this pressure barrier so similarly to Tampa nodding and constrictive pericarditis you have decreased venous return and constriction of the heart next is a pulmonary embolism now let's say a patient falls and breaks their leg and their leg is put in a cast to immobilize it so this immobilization may actually cause blood to clot because it doesn't move as well back to the heart so blood in one of the deep veins of the leg may clot so that's a deep vein clot also known as a deep vein thrombosis which we also like to call a DVT deep vein thrombosis in the medical community so this DBT may potentially break off and when a clot breaks off it's known as an embolism so it amble eise's and you can see that it can fit in the heart but it gets stuck in the lungs in the pulmonary arteries and if it's a big enough clot it can be so severe that when the heart tries to pump blood from the right side of the heart can't really make it to the left lung so blood can only go to the right lung in this case so only one pulmonary vein is returning blood to the heart so only so much blood can be squeezed back out to the brain as well to the organs and other parts of the body the final obstruction that I'll talk about is stenosis aortic stenosis aortic stenosis is narrowing stenosis means narrowing so this is narrowing of the aortic valve so here's the aortic valve and it actually has three leaflets and your entire life these leaflets are going to open and close allowing blood to be processed through the heart now as a patient ages calcium that's in the blood may start to get stuck on these valves this little yellowish orange is calcium depositing on the valves this cause are the valves not to be able to open and close quite so smoothly and in fact deposition can get so bad that it really narrows the valve so you can see when even when the valve tries to open there's only really a small area that blood can pass through so if it's severe enough it can cause obstructive shock so what sort of labs would you want to get for a patient who has obstructive shock first of all you want to get your typical lab value such as a serum lactate or in ABG arterial blood gas so this allows you to so these are your typical values that you'll get in any sort of shock but you also maybe want to get other laboratory and diagnostic tests that can help you diagnose in obstructive shock so I won't go into too much detail but the idea here is you want to use tests that will help you diagnose these specific conditions so for example cardiac tamponade and constrictive pericarditis you might want to use an ultrasound of the heart an echocardiogram in the case of tapenade for example it can show you that there's blood or fluid accumulation around the heart for something like a tension pneumothorax maybe getting an x-ray will help you diagnose this disease or better yet there's a clinical way to diagnose so I want you to go ahead and fill your throat now when you feel you can tell it's in the middle for you however in a patient who has a tension pneumothorax it might be deviated towards one side or the other so for example if a patient has a right tension pneumothorax as we see here the trachea is going to be pushed along with all the other organs and be deviated to the left side of the patient so a clinical observation like that can help you save a patient's life because you can immediately diagnose and treat the patient so what should we do to treat obstructive shock the major way to treat obstructive shock is to relieve the obstruction relieving the obstruction can actually stop the shock altogether very quickly so for example in a tension pneumothorax once diagnosed you can treat immediately with needle thoracostomy and when needle thoracostomy is insertion of a hollow tube into the chest wall and that allows all this air that is accumulated to escape out and relieves the tension in the thoracic cavity if aortic stenosis is the problem maybe a new valve known as a valvuloplasty is required pulmonary embolism dissolving this embolus or removing it directly by guiding a catheter into the heart and grabbing hold of this embolism and for something like tamponade you can take a needle into this pericardial cavity and draw out the fluid so treatment of obstructive shock relieve the obstruction