Alright, so when we treat hemorrhagic shock
our big goal is to restore adequate circulating volume.
So hemorrhagic shock is all about empty vasculature.
The blood instead of being in the vessels where it belongs is somewhere else,
either in the body or on the floor
so we wanna restore adequate circulating volume.
This is gonna result in normalization of the vital signs
and you’ll see those vital signs normalize in real time
if your resuscitation is adequate.
So there are specific things that we wanna do
while we’re resuscitating somebody on hemorrhagic shock.
We wanna make sure we have good IV access.
We wanna make sure that we are giving them appropriate fluids
but we don’t wanna give too much fluid.
You don’t wanna replace too much of the body’s blood volume with salt water
so we wanna also initiate blood product replacement when it’s indicated.
I do wanna emphasize that the goal of treatment
is not to normalize the blood pressure.
The goal of treatment is to provide adequate circulating volume.
So your patient may be a little bit hypotensive
and that’s actually okay as long as they’re able to perfuse their vital organs.
In fact, if you take them back to a normal baseline blood pressure for them
that’s gonna actually increase hydrostatic pressure in the vasculature
and could potentially worsen bleeding so we call it permissive hypotension.
We wanna get our patients up to a mean arterial pressure of 65 or 70
but not much beyond that
because that’s gonna be enough to give them organ perfusion
without exacerbating their bleeding. So what is adequate IV access?
I know this has come up on multiple lectures
but just to remind you it is two large-bore peripheral IVs.
If you can’t get two large-bore peripheral IVs for whatever reason,
your other options are an intraosseous line or what we call a trauma line
which is a large caliber central venous catheter that’s used in trauma resuscitation.
I do wanna emphasize that regular old central lines
are not appropriate for trauma resuscitation.
They’re very, very long and very thin and there’s a lot of resistance to flow through them
so you really can’t get the kind of volume that you need
for somebody in hemorrhagic shock through one of those central lines.
If you are gonna use central access,
please place a dedicated trauma line which is large enough in caliber
to allow you to give the volume of fluid and blood that you need.
When we start off with volume resuscitation we almost always begin with crystalloid.
Our options again are normal saline or lactated ringers.
We’re always gonna use isotonic formulations and the most we’re gonna give is 2 liters.
We don’t wanna replace too much of our blood volume with salt water
because crystalloid does not have hemoglobin in it.
It doesn’t have oxygen carrying capacity.
It doesn’t have clotting factors.
It doesn’t have platelets.
So it’s not actually a substitute for the biologically active substances in blood.
If we’re still in hemorrhagic shock after 2 liters of fluid,
we wanna switch over to blood products at that point
and what we’re gonna use is universal donor blood
or what we call in our institution “trauma blood”.
Now, this is a blood product that comes from typically “O” positive donors.
We all know that “O” negative is the true universal donor,
however, that’s a relatively rare blood type
so we only use “O” negative in reproductive aged women.
“O” positive is appropriate for men for whom Rh isoimmunization is not an issue.
We’re gonna start off with packed red blood cells,
however, for giving large quantities of packed red cells
we might wanna think about plasma or platelets in that setting
so that we’re not diluting out the clotting factors and undermining our own hemostasis.
Crossmatched blood is not gonna be available immediately in the initial resuscitation setting
because it takes time for the blood bank to crossmatch units of blood for your patient.
It’s simply not something that can be done instantaneously
so we’re always gonna start off with universal donor blood,
but once crossmatched blood becomes available you should definitely switch over to that.
It has a better safety profile but that’s typically gonna be an hour or two
before you can get access to crossmatch blood products
so you should not hesitate to use universal donor blood in the beginning of the resuscitation.
Now, one question that my students ask me a lot is how much blood should I give?
How much fluid should I give?
How much is too much?
And the answer that I always give to that question I think frustrates them
but the correct answer is enough.
You wanna give enough blood or enough fluid to maintain your patient’s circulating volume
and perfuse their tissues.
For some patients that might be half a liter of crystalloid,
for other patients that might be 10 units of packed red cells.
It really depends on the degree of bleeding,
how rapidly the patient is losing blood,
how severe their symptoms are and you’re going to titrate the amount of fluid and blood
that you give to each patient to their own individual physiologic needs, okay?
But I do wanna emphasize that there are injuries that typically require large quantities of blood.
If your patient has a great vessel injury that they’re bleeding briskly from
you’re gonna basically have to pump blood into them as fast as they’re putting it back out
and that can take units and units of blood
and you shouldn’t hesitate to use whatever is necessary.
Now, a lot of times students say well when should we start thinking about vasopressors?
Should we be starting norepinephrine drips in these patients
if we’re not able to get them perfusing adequately with just volume alone.
And the answer to that question is no!
Hemorrhagic shock is treated with volume.
Hemorrhagic shock is a disease of blood loss.
You’re not gonna make it better by squeezing harder on the vasculature.
You need to make it better by putting blood back into the vasculature.
There’s no role for pressors whatsoever in the management of hemorrhage
and physiologically when you think about it, it doesn’t make sense, right?
You’re not going to improve circulating volume by increasing your vascular tone and in fact,
vasopressors work by stimulating catecholamines.
That’s what norepinephrine does,
that’s what epinephrine does et cetera and that’s what you’re body is already doing.
That’s how your body is making you tachycardic in response to blood loss.
That’s how your body is racing your diastolic blood pressure
and narrowing your pulse pressure.
It’s all being done by your indigenous catecholamines
so adding additional catecholamines to the system doesn’t actually make sense.
It does create significant risk but it doesn’t offer a whole lot of benefit so don’t do it.
So bottom line is if vital signs aren’t getting better with volume resuscitation
and you haven’t given enough volume,
do not reach for vasopressors for patients with hemorrhagic shock.