CARDIAC MONITORING

Place all patients with chest pain or SOB on a cardiac monitor to detect any arrhythmia that may occur and monitor heart rate.

Patients with PEs will often have sinus tachycardia that does not completely improve with fluid administration.

Patients with PEs can have all sorts of arrhythmias including:

• Atrial fibrillation
• bradycardia
• RBBB
• PVCs
• VTACH/VFIB

STAT EKG

All patients presenting with chest pain and/or SOB should have an EKG obtained within 10 minutes of arrival.

This is primarily to rule out any STEMI or ischemia. However, large PEs can cause significant right heart strain.

While they occur in < 10% of patients, signs of right heart strain on an EKG include:

• Right heart strain pattern
• S1Q3T3

Oxygen Support

If the patient is significantly hypoxic or tachypneic, apply 2-4 L/min NC. If this is not enough to titrate SPO2 > 90%, apply a non-rebreather.

In these cases, BIPAP or Intubation may be needed.

Oxygen Support

Start a peripheral IV at least 18-20g in an AC line, as there is a high likelihood that these patients will be needing a CTA. These large bore IVs are needed to inject high-pressure dye.

While drawing blood, make sure to draw a blue top as D-dimer may be ordered, as well as a PT/INR.

WELL’S CRITERIA

The Wells’ Criteria for PE is a clinical tool that is able to be used to determine the risk of a PE.

This assigns points to each of the following:

• Signs of DVT: 3 points
• PE #1 likely dx: 3 points
• HR > 100 bpm: 1.5 points
• Immobilization x 3 days: 1.5 points
• Surgery within 4 weeks: 1.5 points
• Previous PE/DVT dx: 1.5 points
• Hemoptysis: 1 point
• Malignancy w/ tx in last 6mo or palliative: 1 point

Once you calculate their score, you can stratify their risk into one of the following:

• Low risk: 0-1 point
• Moderate: 2-6 points
• High risk: >6 points

Scores of 4 or less with a negative D-dimer can effectively rule out a PE.

D-DIMER

One way to minimize radiation is to obtain a D-Dimer in a patient with low to moderate suspicion of a PE.

A D-dimer is a byproduct of fibrin which is increased in the blood whenever there is a blood clot.

While this is a great test to see if there is a possibility of blood clots within the body, it is not very specific. This means that a negative D dimer (less than the threshold) is a pretty good way to tell if someone doesn’t have a blood clot. However, a positive D-dimer doesn’t necessarily mean there IS a blood clot in the body.

Any bruise or minor injury can cause elevations in D-dimer, as well as pregnancy, heart disease, infections, and more.

This means that if a D-dimer is above the threshold (around 230 but depends on your lab), then the Provider is pretty much forced to get a CTA to see if their truly is a PE.

If a D-dimer is less than the threshold, then a PE can usually be ruled out. However, this is only the case is clinical suspicion is low to moderate.

In patients who have a high likelihood of a PE, a D-dimer can miss a PE up to 15% of the time!

OTHER LAB WORK

A troponin should be ordered in patients with chest pain and/or SOB. This can sometimes be mildly elevated in PEs, or significantly elevated if a PE causes a STEMI or NSTEMI.

A BNP may be ordered if there are s/s of heart failure.

Renal function should be checked before a CTA can be done, to make sure their kidneys can handle the dye. A GFR > 30 is usually adequate to obtain a CTA.

Coagulation studies may be performed inpatient to see if there are any genetic mutations predisposing the patient to forming thrombi.

ABGS

An ABG may be obtained if the patient is in significant respiratory distress or has altered mental status.

With a PE causing significant distress, you’ll typically see the following results on an ABG:

• PaO2: Low (<80 mmHG)
• PCO2: Low (<35 mmHG)
• pH: Alkalotic (> 7.45)
• HCO3: May be low (<22 mEq)

CXR

A chest x-ray (CXR) will almost always be ordered on patients who are suspected of having a PE, because these can rule out some other causes of chest pain and SOB such as a pneumothorax or pneumonia.

However, a CXR is not going to pick up a pulmonary embolism. A CXR may show nonspecific signs including atelectasis or effusions, but often will be completely normal.

In order to actually see the pulmonary embolism, a CT pulmonary angiography (CTPA or just CTA) is required.

CTA

Angiography is when a radiopaque dye is injected into the patient’s vein in order to get a good look at the patient’s vasculature during a CT scan. This can be timed to look at specific areas of the heart.

CT Pulmonary Angiography is when this is done to look at the pulmonary arteries and veins. This means the radiologist can directly visualize pulmonary embolisms.

If the patient’s GFR is <30, we generally avoid contrast dye. However, this may be completely facility dependent.

If a patient cannot be given the dye (GFR < 30 or anaphylactic reaction), the alternative test is to obtain a V/Q Scan.

V/Q SCAN

A VQ scan is a nuclear medicine test where they use radioisotopes in conjunction with X-rays to see if there are any ventilation/perfusion mismatches. Well this is not as definitive as a CTA, it does give probabilities of there being a PE, such as a “very low probability”.

PARENTERAL ANTICOAGULATION

Treatment for pulmonary embolisms primarily involve anticoagulation.

In the hospital setting this is usually IV unfractionated heparin. This Heparin is given as a Heparin drip, which is titratable depending on PTT levels. Each facility should have their own heparin drip protocol.

In general, a bolus dose is given IV (can push fast), and then a slow drip is started. The PTT levels are usually checked every 6 hours but will depend on the protocol.

SQ Lovenox is an alternative to IV heparin, and is given in a dose of 1mg/kg BID.

But how does anticoagulants really help if the blood clot is already there? The role of the anticoagulants are to prevent further clots from forming, as well as to stabilize the clot from moving. This can be especially helpful if there is a DVT or an atrial thrombus within the heart. These can embolize and cause further PEs or even strokes.

ORAL ANTICOAGULATION

Sometimes the patient can be started directly on an oral anticoagulant and discharged home if they are otherwise stable, but this will depend on the Provider and the facility standards.

Once the patient is stable enough for discharge, they are started on long-term oral anticoagulation, such as Eliquis or coumadin.

Patients with very recent surgery, hemorrhagic stroke, or active bleeding are not started on anticoagulation.

Patients will often need to stay on the anticoagulation for at least 3 months, but sometimes longer. The blood clot should be reabsorbed by the body in about 6 weeks, but will depend on the size of the thrombus.

Some patients will require life-time anticoagulation if they are found to have any genetic predispositions to blood clots. This is also true for patients with atrial fibrillation.

IVC FILTER

An inferior vena cava filter, commonly referred to as an IVC filter, is a device that is sometimes placed to “catch” clots before they enter the right atria.

This is usually placed in for patients who cannot be on anticoagulation, or those who have gotten repeat PEs despite anticoagulation therapy.

They can be temporary and need removed eventually, but some that are placed are permanent.

THROMBOLYTICS

In patients who are hemodynamically unstable from their PE, thrombolytic therapy can be given to dissolve the clot. This is like TPA in a stroke, but given for a PE.

However, there are many contraindications to thrombolytic therapy, and there is a risk of bleeding.

PROCEDURAL REMOVAL

An Embolectomy can be performed if needed and if the facility is capable of doing so, particularly when thrombolytic therapy is unsuccessful or cannot be used due to contraindications.

There are additional procedures that can be done to retrieve / break up the clot including: Ultrasound-assisted thrombolysis, Rheolytic embolectomy, Rotational embolectomy, Suction embolectomy, Thrombus fragmentation, Surgical embolectomy.

Many facilities will not have these capabilities, but most should have thrombolytics.

PARENTERAL ANTICOAGULATION

Treatment for pulmonary embolisms primarily involve anticoagulation.

In the hospital setting this is usually IV unfractionated heparin. This Heparin is given as a Heparin drip, which is titratable depending on PTT levels. Each facility should have their own heparin drip protocol.

In general, a bolus dose is given IV (can push fast), and then a slow drip is started. The PTT levels are usually checked every 6 hours but will depend on the protocol.

SQ Lovenox is an alternative to IV heparin, and is given in a dose of 1mg/kg BID.

But how does anticoagulants really help if the blood clot is already there? The role of the anticoagulants are to prevent further clots from forming, as well as to stabilize the clot from moving. This can be especially helpful if there is a DVT or an atrial thrombus within the heart. These can embolize and cause further PEs or even strokes.