So what do we do about dissections?
Well, like I said, it's based on classification,
so all Type A’s require emergent surgical intervention.
If your ascending aorta is involved with the dissection,
it needs to be managed operatively.
Type B’s, are typically managed medically except in the case of complications
and we'll talk about that in a second.
For ED purposes we're gonna manage all dissections the same way
with the one important exception of consulting cardiothoracic surgery
for patients who do require surgical management.
We should also remember that aortic dissection is always an emergency,
so just because your patient presents stable right now,
it doesn’t mean they're gonna be stable 30 minutes from now,
and it's really, really, important that you expedite treatment for this patient
and take this disease process very seriously.
So as far as what we're gonna do for these patients in the ED
we're gonna of course give them oxygen to ensure adequate saturation
and optimize oxygen delivery to the organs.
We're gonna have them on cardiac monitors
and we're gonna really keep a hawk’s eye on their vital signs.
Patients with aortic dissection can decompensate very quickly,
and we wanna make sure that we are completely
on top of their physiologic status at all times.
We wanna make sure we have adequate vascular access.
We talked about what that means before,
but just to remind you that is two large bore IVs
at minimum or central access.
So we really wanna make sure we have stable, reliable, large bore access
so that if we need to we can rapidly resuscitate the patient with fluids or blood.
Speaking of blood, we wanna make sure we have typing cross matched.
And we wanna cross match the patient
for a significant number of units of blood, typically four to six.
Remember one of the risks of aortic dissection is rapture of the aorta,
and as you can imagine that's gonna lead to significant blood loss
and we wanna be prepared to deal with that if it happens.
If the patient is hypotensive we definitely wanna give them IV fluids and or blood
if we're concerned about the possibility of rupture,
and we wanna keep a very close eye on their hemodynamic status.
We're always gonna monitor urine output
because the aortic dissection can involve the renal vessels
and we wanna make sure that we're not missing any early evidence of renal ischemia.
And we wanna place an arterial line
so that we can really keep minute to minute tabs on our patient's blood pressure.
It's not good enough to be checking blood pressures every few minutes in these patients.
We really wanna know from one minute to the next
what's gonna with their blood pressure because as you'll see in a moment
medical management involves blood pressure optimization.
So when do we consult our surgical friends?
Like I said before, for any type A
we're gonna contact immediately.
If it involves the ascending aorta
we need to make sure we get surgery on board.
And that's because these patients are at very high risk
of developing cardiac complications.
Cardiac tamponade, myocardial ischemia,
or acute aortic valvular insufficiency.
All of these can be deadly complications
and we wanna make sure that we have a surgeon on board
to help us deal with them.
For Type B’s, the management is gonna be primarily medical.
So we're really gonna involve surgery
if we have a complication or we suspect an impending complication.
So patients who are ruptured or we suspect may have impending rapture,
we're gonna get surgery involved.
If the dissection is rapidly propagating so their clinical status is changing,
there is evidence of new vessels getting involved,
we're gonna want surgery to help us out there.
If they have an enlarging wall hematoma
that's the sign of active bleeding
and again may merit surgical consultation.
If they're developing aneurysmal dilation of the aorta
that could place us at risk for rupture
and we wanna get surgery involved for that.
And if there's any compromise of major aortic branches,
so if they're infarcting their mesenteric vasculature,
if they're infarcting their kidneys,
if they're showing stroke symptoms,
we wanna consider whether surgery might be warranted
in those patients to limit the extent of propagation of the dissection.
So for Type B's,
any rupture, any bleeding, any significant complications,
get surgery on board.
And when in doubt, it's always a good idea to involve a surgeon.
The worst thing they're gonna say is,
"No, we don’t need to do surgery for this,"
but you definitely wanna make sure that you have them on board
for any case where you suspect you might.
As far as our medical management goes, our biggest goal
is to stop further propagation of the dissection
and to prevent rupture.
So we can't do anything about the blood
that's already dissected into the aortic wall,
but we wanna keep that dissection from getting bigger
and involving more of the aortic branch vessels.
And we wanna prevent aneurysmal dilation and rupture.
The way we do that is by decreasing blood pressure
so we wanna lower the hydrostatic pressure inside of the aorta
and we wanna decrease the shear force on the aortic wall from cardiac contraction.
So basically lower the pressure so less blood is pushed out
and decrease the continual shear stress on the wall
by causing the heart to beat a little bit less forcefully.
The best way to accomplish both of those goals with a single drug is beta-blockers.
So we wanna beta-block these patients quite aggressively.
This is one of the few situations in medicine
where you wanna lower the blood pressure down to normal
regardless of where your patient started.
Typically, when patients come in with really elevated blood pressures,
they have systolics of 180 or 200 or 220,
we only lower them modestly.
We only lower them to maybe 20% of their original mean arterial pressure.
However, with aortic dissection,
we wanna normalize that pressure as quickly as we can
with the goal of preventing complications of the dissection.
So this is gonna take down our heart rate,
it's gonna decrease myocardial contractility
and ultimately lower aortic pressure and shear stress.
So whenever we treat dissections,
or really any other life-threatening pathology,
it's always a good idea to use an agent that can be given as a continuous infusion.
That way you can turn it up, turn it down, turn it off if you need to.
You can continually adjust
how you're manipulating the patient’s physiology
in order to achieve your treatment goals.
So typically we use Esmolol, which is a very short acting beta-blocker
that's given as a continuous infusion.
Labetalol can also be used in some settings as well.
So once we've maxed out our beta blockade,
if we're still not getting a good handle on the blood pressure,
we wanna add an additional agent.
Nitroprusside used to really be the agent of choice,
but now we often use ACE inhibitors or calcium channel-blockers.
There's no one agent that’s been shown to yield better outcomes than any others.
A lot of people will use an Enalaprilat or nicardipine as alternatives to nitroprusside
to get the blood pressure under control if beta blockade alone isn't doing it.
Again, we wanna give these drugs as continuous IV infusions,
we don’t wanna be giving boluses that we can't control the effect of in an hour.
We wanna make sure
that we can really carefully adjust the patient’s parameters as needed.
If our patients become hypotensive,
of course we're gonna turn off any infusions that we're giving
that would be lowering the blood pressure
but we're gonna also replete volume.
So we wanna make sure they have adequate circulating volume
by giving them fluid first, and we're only gonna use vasopressors
if we're certain that our patient is euvolemic
and we've addressed any hypovolemia or bleeding.