hey everyone we're back with another video in our post-operative complication series and for this one we're going to be talking about hypotension or circulatory shock and what i think is going to be important about this video is we all learn this giant laundry list of problems and types of shock in medical school but then when we're faced with shock in a clinical scenario it can be incredibly overwhelming to feel like you have to go back and make sure you can remember every different type of shock and oh what if it's this one or this one or that one i think it can be really helpful to think about a specific clinical situation like a post-op patient and when we have a patient like that in shock to be really clear about what are the most common types of shock that we should be thinking about and allow us to have a nice calm methodical approach to this that can free up our mind to do that more complex diagnostic thinking uh and also make sure that we're not spending uh too many mental resources going down the rabbit hole of oh my gosh i have to rule out the zebra cause of shock uh which could detract you from the much more common and likely diagnosis to do that i just wanted to do a brief review of the different types of shock and maybe even before we do that we should talk a little bit about what shock or hypotension is and that's typically defined as a mean arterial pressure of less than 65 millimeters of mercury so a map less than 65. of course a blood pressure is just a number and there are many physical findings and other findings that we can measure that are related to shock such as looking at urine output which is indicative of renal dysfunction if your patient has altered mental status they might not be perfusing their cerebrum very well etc so with that in mind let's talk briefly about our shock states and this list is probably a little bit shorter than the types of shock you remember memorizing in medical school but this is really about shock states and and most types of shock will fall under one of these four states and i've put them in order of what are going to be most to least common in your post-operative patients so here we're thinking about distributive shock this is things like sepsis sepsis and sepsis sepsis it's very common very common post-op so that's why i want to first come to your mind when you're thinking about shock in the post-op patient other types of disre distributive shock that are more rare are things like anaphylaxis which would usually be related to a medication a new medication given in the perioperative period or something like neurogenic shock but that is very rare post-op much more common in our trauma population it should be pretty obvious if your patient is paralyzed or not so really distributed i want you to mostly think about sepsis hypovolemia this just means having too little fluids uh in your bloodstream sorry i should go back even so distributive shock sepsis what does that mean right so let's say this is a blood vessel right if it's its normal size it has its normal amount of fluid in it everything's fine the blood pressure is normal but in some sort of setting of extremely profound inflammation now that vessel dilates it becomes leaky right there's holes in your capillaries so fluids leaking out and the space is bigger and now you have that same amount of fluid but it's not enough uh to take up the space so that is a distributive problem because the fluid is too little to distribute to this entire new um potential space that's been opened up by this inflammation and then hypovolemic shock is when blood vessels space are normal but for some reason there's just not enough fluid in here you're in the post-op patient this is usually just a lack of fluids given the operating room surgery and open abdomens uh cause a lot of insensible losses so people need a lot of fluid replacement and of course the other major cause would be if you have a hole in a blood vessel somewhere and you're just bleeding out either usually into the abdomen or some sort of potential space in the body and then your other types of shock are going to be much less common in the post-op patient so cardiogenic shock that just means uh the blood vessels are normal or usually just clamp down even but your heart is not able to function well enough to push blood through the circulation this could be because their heart muscle is just not working well enough some sort of acute usually acute on chronic heart failure it could be some valuable disease it could be a post-op arrhythmia that's overwhelming the ability of your heart to provide cardiac output and then finally obstructive this is these are really rare types of shock but in my experience these are types of shock that people spend in an ordered amount of time kind of really uh freaking out about in the initial setting when it's actually quite rare and that they probably would be better off thinking about some of these other ones but some examples of this would be things like pulmonary embolus pneumothorax cardiac tamponade and so of course important causes and certainly if you see somebody who's incredibly hypoxic along with their hypotension you might be thinking about pe or if they have the bulging neck veins or no breath sounds on one side it's like being with oral stuff like that so obviously we don't want to not think about them but if if one of these is not really calling out to you from the clinical picture i wouldn't spend a ton of time thinking about obstructive shock and why do i say that so here's some data from a couple of new england journal articles there's a 2013 article in the new england journal on circulatory shock that cites a previous article in 2010 uh a big rct of different types of pressure treatments for shock but the point is they looked at these 1600 patients and keep in mind these are not surgical patients these were even medical patients and ask what are the most common types of shock for people admitted to an icu we see that distributive shock is by far and away the most common it's over half of cases it's over 40 percent uh absolute percentage points higher than the next most common cause of shock which is hypovolemic now i'm saying hypovolemic rather than cardiogenic even though these two are technically tied because i remind you that these are all um all comers as opposed to just surgical patients so in surgical patients you're gonna have less of this cardiogenic shock and probably a lot more of the hypoblemic shock so that's just why i'm emphasizing really distributive remember thinking about sepsis anaphylaxis and the hypovolemic thinking about under resuscitation with fluids and thinking about uh bleeding that are really going to be important in our post-op patients cardiogenic of course is still possible but once again it's a relatively low percentage and obstructive is just extremely rare two percent of all patients probably even lower percentage of surgical patients so of course something to still keep in mind but really i want us to be focused on the distributive and hypoplasmic causes of shock in our postdoc patients all right so here's our example page patients got a low blood pressure we'll assume that they took this correctly and rechecked it it's still low they're asking you to please assess this patient and so if we're thinking again remembering our hypoxia videos there's some things where we have to act where we have to prescribe treatments with incomplete data and this is certainly one of them you can't just leave a patient hypotensive until you have a diagnosis so we we see once again we've got this outer algorithm where we have to deal with the symptoms with an initial treatment uh without a diagnosis while we're doing that treatment we can work on our work up thinking about moving our patients to a different level of care and then only then can we really give a ton of thought to getting really granular about our differential and our diagnosis so our kind of uh initial or stabilizing treatments for shock once again a low mean arterial pressure usually less than 65 the first treatment especially again in post-op patients is going to be fluids fluids fluids in most patients these are going to be some sort of isotonic fluid for example lactated ringers or normal saline if your patient is highly likely to be bleeding maybe they're a trauma patient that's been bleeding or you have a patient with a drain and you see blood in the drain then that fluid is going to be blood products right packed red blood cells plasma etc thinking about a balanced blood resuscitation but either way the first thing you should be trying when your patient is hypotensive is some sort of fluid bolus even if your patient has a cardiac history if patients with a low ef or um poor cardiac function they still need fluids if they lack fluids right like a pump even a bad pump needs fluid to to be able to pump that fluid forward so don't be afraid to try a fluid bolus in a patient that may have a history of heart failure especially if they're acutely hypotensive and we're thinking about them being a post-op patient where they're highly likely to have some sort of distributive or hypovolemic or hemorrhagic shock just certainly be a little bit more judicious maybe if they're not responding you don't just keep slamming them type thing but certainly fluids fluids fluids is the first thing you should be thinking about and of course to administer these fluids you're going to need good iv access that's going to go into our next treatments as well so a patient with hypotension uh usually i'm getting that page i'm calling them back and saying how's our ivs uh maybe if we don't have good access we're calling for some sort of assistance sos team to help us get good iv access but that's going to be crucial to our treatment of this patient and then next line sorry dog scratching so this next line of treatment if you're giving fluids it's not enough not working we want to think about vasopressors we could have a whole talk on just pressers but the short answer is norepinephrine it's almost never wrong to give norepinephrine as your first line presser there are some situations where other pressures are better but norepinephrine is rarely wrong right there might be something more optimal but you start with norepi then when you have a little bit more time a little bit more stabilization you can really get into the weeds and figure out if there might be a better choice but if you're you know new to hypotension new to treating this patient and you're in a really stressful situation just choose norepinephrine don't think about it anymore let your mind deal with the rest of this usually chaotic situation and then another thing to think about is ventilation so when patients are critically sick for a variety of reasons they'll usually become hypoxic to some degree you want to be supporting that and have a low threshold to potentially intubate a patient that's doing really poorly and finally down here i have other and this just means that of course these are not the only things you're doing especially in some of those special cases where you're highly suspicious of maybe some sort of obstructive shock if your patients may be having terrible chest pain you think they're having a heart attack right like obviously the situation might call for something else but in general undifferentiated hypotension you're going to be thinking about fluids you'll be thinking about pressures and you're going to be thinking about ventilation all right and then the workup is next and this is really kind of the kitchen sink approach right hypertension is no joke we want to get right on top of it and you need these things kind of cooking so you can make decisions fast because this patient's in a very acute situation ideally your patient is awakened alert and you can talk to them but if they're not you can still at least do a physical exam you can talk to the nurse and the other caregivers of the patient that have seen them recently get a good sense of the scenario that will usually give you some serious clues about what sort of shock this might be of course vital signs as well go along with that and then when we're talking about labs just the kitchen sink cbc basic malleolic panel this is looking for infection or bleeding the basic metabolic panel will look at things like kidney function any bad electrolyte arrangements lactate's a big one in shock and elevated lactate is not a great sign and then an arterial or venous blood gas will give us information about their ph as well as their pco2 thinking again about our common causes with septic shock being so common usually you want to be thinking about some sort of infectious workup uh the basic kind of most rudimentary infectious workout is two blood cultures your analysis and the chest x-ray i put imaging down here you're usually going to be getting some sort of imaging depending on your suspicion if you have blood coming out of a drain maybe you're getting a cta of the abdomen if you just think they're infected somewhere you're not sure maybe it's a leak in the belly you might be getting a ct abdomen pelvis or chest abdomen and pelvis really there's no one type of imaging um but just be thinking about how that might be needed in your diagnosis based on the scenario in front of you and then finally we have this other category again once again the guys if someone's having horrible chest pain grabbing their chest do you think they have a heart attack or their heart rate's 160 and irregular you want to be analyzing that further with something like an ekg if you thought they had tamponade for whatever reason there's things like focused cardiac ultrasounds etc i mean the the causes of shock like i said at the beginning are broad and varied uh but at the very least i know in any patient with hypotension i'm gonna be throwing these common things at them and then i because i know that this is what i want every time i can give some some real deep thought to the other imaging or studies that might be needed as long as i follow this basic approach finally we talked about this in our last video always remember your spectrum of level of care from lowest up to highest in icu most patients with severe hypotension are going to end up in the icu especially if they need pressers they almost always need to be in this sort of highly monitored setting and then once we've done all this we can step back a little bit and think a little bit more deeply about the differential uh you should be getting your laps back but i want you to remember this whole time uh remember that common things are common be thinking about sepsis be thinking about bleeding um and don't let something super rare like some of these obstructive causes of shock really draw you away from um considering how your patient may be septic or bleeding if they're postoperative the way i like to think about it is you know is it more likely for the patient's body to have randomly kind of broken like their heart just gave out on them randomly or or some sort of their normal homeostasis just happened to give out after surgery or something external like an organism bacteria or some sort of technical issue or bleeding related to their surgery caused the problem those are like we said much more common even in all comers as causes of shock but especially in the post outpatient it can help keep you a little bit centered and keep your thinking more clear if you're if you're really focused on these distributed and hypoblaming causes of shock all right that's it for this video this is for educational purposes only do not use this to diagnose or treat any diseases and we'll see you next time