So in terms of general management,
You know, I talked about how shock is a disease of tissue level hypoxia.
So we wanna be really attentive to airway and breathing for these patients, right?
Everybody should get supplemental oxygen no matter what.
Shock is also a disease of circulation,
so we wanna make sure that everybody has adequate IV access
and once again, that is two large bore IVs.
We wanna make sure we can give high volume fluid resuscitation if we need to.
We wanna also, always consider a fluid challenge in shock.
Now, not every patient is gonna benefit from fluids.
As you can imagine in cardiogenic shock
when your problem is really lack of cardiac squeeze.
You know, increasing the amount of circulating volume
isn't gonna do you a heck of a lot of good
because these patients aren't typically coming in hypovolemic.
However, in most other causes of shock,
filling up the tank is a really good idea and might produce some clinical benefit for your patient.
But the most important thing to think about in shock is what's causing it
and how can I reverse that underlying disease process.
Shock is all about the ABC's.
Let's start off with A and B
and just remind you why airway and breathing are so important.
So again, we wanna give supplemental oxygen
to get a saturation of 95% or greater.
Now, if your patient has pulmonary disease,
they might be okay at 92, 93
but we definitely wanna raise the oxygen saturation
up to a physiologic level for that patient
because this is a disease of hypoxia.
So we wanna make sure that their saturation is adequate,
making their arterial oxygen content adequate
to ultimately allow them to deliver oxygen to tissues.
Now for most patients,
simple supplemental oxygen is gonna be fine,
but if your patient has really severe shock
or if they have significant respiratory distress,
you might need to think about intubation
in order to decrease their metabolic work of breathing
and enable them to optimize their oxygenation.
So, the amount of intervention you're gonna need for airway and breathing
is gonna vary based on the patient’s clinical status.
Let's move on now to C.
So we always wanna think about fluid resuscitation for our patients in shock.
Like we said before, IV fluids increase preload.
When I increase my circulating blood volume
I'm gonna increase the amount of blood that's in the ventricle at the end of diastole
which according to the Frank-Starling Law,
is gonna then increase my stroke volume
which in turn increases my cardiac output,
ultimately allowing me to better deliver oxygen to tissues.
So, this is really all about the physiology.
When I optimize my preload, I optimize my cardiac output
and I do a better job getting oxygen
where it needs to be at the tissue level.
For vascular access which is also part of C,
remember we wanna make sure that we're able to give large volumes of fluids
if it's necessary.
So that means we need to minimize resistance to flow
through whatever vascular access devices we use.
So we want large diameter devices that are short as possible.
We all remember Poiseuille's law
which tells us the radius of a tube is the biggest determinant to how quickly fluid can flow through it.
So a big diameter tube is gonna let us give a lot of fluids quickly
and a short tube is gonna let us give a lot of fluids quickly
which is why peripheral IVs are really better than central venous access devices
although of course, if you're not able to get adequate peripheral IV access
you will need to place a central line.
You're just gonna wanna use the largest caliber one you can get your hands on.
When we give fluid, we're always gonna start off with isotonic crystalloid
by which I mean normal saline or lactated ringers.
However, we don’t wanna be giving fluid indefinitely.
At some point, if the patient is bleeding or has significant anemia,
we're gonna wanna think about switching over from crystalloid to blood products.
Consider transfusion in patients and whom it's indicated
based on their either clinical bleeding status
or their laboratory measured hemoglobin.
The amount of volume that you have to give
is gonna vary according to what's going on with the patient.
So if it's a patient in a hemorrhagic shock
who has a major bleeding source, they might need liters of fluid
and units and units of blood in order to maintain their circulating volume.
However, if it's a patient who has a mild myocardial infarction
and they started off pretty much euvolemic,
you might not need to give them any fluid or only a very small amount.
So you always wanna make sure that you're reassessing your patient frequently
while you're giving fluid or blood,
that you're considering their underlying physiologic state
and their comorbidities, and you're using their response to treatment
to guide how you continue with their resuscitation.
So, bottom-line take home points about shock
is you can always think about shock as tissue level hypoxia
and when you think through that physiology,
it's gonna point you in the right direction
at the ABC interventions that you need to perform to get a patient out of shock.
There's lots of different disease states that can cause shock
and the presentation of shock clinically is gonna vary
based on what caused it and how well-compensated the patient is.
Initial treatment is all about the ABCs
so that's gonna involve supplemental oxygen and airway management if it's necessary,
also intravenous fluids and potentially blood products.
Thank you very much.
I hope you found this useful.
It's a review of the physiology of shock and how to manage it.