00:00
So when we’re thinking about other testing for patients
in whom we’re thinking about a pulmonary embolus,
we wanna go back and start thinking about keeping our differential broad.
00:10
So we’re thinking about a pulmonary embolus but we also wanna make sure
we’re thinking about other things potentially as well.
00:16
So we wanna do our basic lab work.
00:18
We wanna get an EKG to assess for any evidence of ischemia, to assess for an arrhythmia.
00:24
Often times when patients come in with shortness of breath or chest pain,
for the most part they’ll get a chest x-ray to take a look
and make sure there’s not something else causing it.
00:33
So chest x-rays can show you if there’s pneumonia,
if there is a pneumothorax, if the lung has collapsed.
00:38
You potentially might wanna get a troponin if you're thinking about a pulmonary embolus.
00:43
A troponin is helpful to evaluate for acute coronary syndromes
but also in patients who have large pulmonary embolus.
00:49
They can have a positive troponin due to the fact that there’s strain placed on the heart.
00:55
You potentially consent a pro-BNP.
00:58
Pro-BNP is thought to be a marker of a strain on the heart as well
and also heart failure and can be elevated in patients who have pulmonary embolus.
01:08
And then our PE specific testing, so the D-dimer is the screening blood test for pulmonary embolus
and as a screening test we send it and if it’s negative we’re done
and if it’s positive then we need to go ahead and do additional testing.
01:23
The last test that we do for pulmonary embolus is a CT angiogram of the chest or VQ scan,
and these are more advanced imaging techniques than a chest x-ray.
01:33
The CT angiogram takes a look at the blood vessels very closely
and it’s a CT scan that’s done with IV contrast
and it’s a good test to look for pulmonary embolus.
01:44
And if the patient is unable to get a CT angiogram of the chest,
they can get a VQ scan and we’ll talk about both of these studies in a moment.
01:52
So let’s go back to calculating our risk score.
01:56
Now we mentioned if our patient is PERC negative,
they have a less than 2% risk of pulmonary embolus
and for this patient who fall into this category there is no indication for additional testing.
02:06
For a patient who is Well’s criteria low risk,
for those patients we wanna think about D-dimer testing,
so someone is positive in the world of PERC and they are low risk in their D-dimer score,
we can go ahead and get a D-dimer.
02:23
If the D-dimer is negative, you can likely stop your work up.
02:26
For patients who are moderate or high risk in Well’s criteria,
those are patients who need additional imaging.
02:34
You don’t wanna send a D-dimer in those patients because you already have a higher suspicion
that the patient may have a pulmonary embolus.
02:40
So when they fall into that category where they’re moderate or high risk in Well’s,
for those patients you can get a CT angiography as the initial testing for pulmonary embolus.
02:49
For patients who can’t get a CT angiography study, they can get a VQ scan.
02:55
So patients who can’t get a CT angiography are patients who potentially have renal disease
because it does involve IV contrast and IV contrast is contraindicated
in patients with severe renal disease.
03:08
Our patients who are allergic to IV dye also cannot get CT angiography.
03:14
You know, subset of patients who is always a little bit controversial
about what imaging study to get are pregnant patients.
03:20
Pregnant patients, generally, CT angiography is actually recommended.
03:25
Meaning, you always wanna make sure that you discuss that with your patient
because it does expose them to some radiation and as well as the baby to some radiation.
03:33
But we generally will recommend CT angiography
because it can tell you if there’s a pulmonary embolus there
but can also tell you whether or not there is other stuff going on in the lungs
that might not necessarily have been seen on the chest x-ray.
03:45
VQ scan does have some limitations that we’ll talk about in a moment.
03:49
Now, I just wanna be clear here that one thing that’s very important to think about
is that you are thinking about your clinician gestalt.
03:56
So we have all of these decision rules but actually there have been lots of studies that show
that clinician gestalt, so whether or not you think that the patient has a PE,
is actually sometimes performs better than any of these testing.
04:09
So we talk about these tests a lot and these decision rules a lot
but really using your medical instincts can sometimes really serve you well in this situations.
04:19
So definitely make sure you’re using these decision rules
but as you get on in your training and in your careers,
your clinical gestalt can really serve you quite well.