Table 25-1. The Pulmonary Embolism Rule Out

Criteria (PERC) for excluding PE without testing.

Age <50 years

Pulse <1 00 bpm

Pulse oximetry >94%

No unilateral leg swel ling

No hemoptysis

No recent surgery /trauma

No oral hormone use

No prior venous thromboembolism

If there is a low clinical gesta lt pretest probabil ity for PE AND all

8 criteria are fulfil led, sensitivity is 97.4%.

PERC rule may not be appl ied if concu rrent beta -blocker use,

transient tachyca rdia, thromboph i l ia, strong family h istory of

thrombosis, patient with an amputation, massively obese (leg

swelling can not be reliably assessed), or basel ine hypoxemia

(<95% long-term).

Based on data from: Kline JA, Mitchell AM, Kabrhel C, Richman PB,

fr Cou rtney, OM. Clinical criteria to prevent unnecessary diag nostic

testing in emergency department patients with suspected pulmonary embolism. }ouranal of thrombosis and haemostasis.

2004;2(8):1 247-55.

Wells rules have been shown to be comparable. In patients

with an "unlikely" pretest probability of PE, a d-dimer

should be ordered. If the d-dimer is negative, no further

testing is required. If the d-dimer is positive, the clinician

proceeds to chest CTA to adequately exclude PE. In

Box 25-1. Geneva Score (Revised and Simpl ified).

The Geneva score is predictive for PE. It was developed in 2001,

revised in 2006, and simpl ified in 2008. The items below are scored

and summed in patients with suspected PE to give a total score.

PE unl ikely if score D-2

PE likely if score � 3

RISK FAOORS

Give 1 point for each:

1. Older than 65 years

2. Previous DVT or PE

3. Surgery requiring general anesthesia OR fracture of the lower

limb in the last month

4. Active mal ignancy (tumor or blood) within the last year

SYMPTOMS

Give 1 point for each:

1. Pain in a unilateral lower extremity

2. Hemoptysis

CLINICAL SIGNS

Give 1 point each:

1. Heart rate 75-94 bpm

2. Deep venous palpation elicits pain and uni lateral edema

Give 2 points for:

3. Heart rate greater than 95 bpm

Table 25-2. Well's crite ria for determining the pretest

probabil ity of pulmonary embolism.

Variable

Hemoptysis

Heart rate > 1 00 bpm

Immobilization (bedrest, except for use of bathroom, for

>3 days or surgery within 4 weeks)

Previous diagnosis of DVT or PE

Points

1 .0

1 .5

1 .5

1 .5

Malignancy (currently receiving treatment, treatment 1 .0

within 6 months, or palliative care)

Clinical signs and symptoms of DVT (objectively measured leg 3.0

swelling and pain with palpation in the deep vein region)

PE as likely as or more likely than an alternate diagnosis 3.0

PE unl ikely D-4

PE likely >4

Adapted from: Wells PS, Anderson DR, Rodger M, et a l . Derivation

of a simple clin ical model to categorize patient's probabil ity of pulmonary embolism: increasing the models utility with the SimpliRED

0-dimer. Thrombosis and Haemostasis. 2000; Mar;83(3}:41 6-420.

patients with "likely" pretest probability of PE, CTA is

obtained (Figure 25-2).

TREATMENT

Oxygen should be administered as needed. Endotracheal

intubation may be necessary for cases of refractory hypoxia.

Vasopressors such as norepinephrine (10 meg/min) are

indicated in patients with hypotension. Large IV fluid

boluses should be avoided. Fluids can exacerbate already

elevated right ventricular pressures, leading to further

compromise of left ventricular outflow and shock.

Anticoagulation is the mainstay of treatment and prevents additional thrombi from forming, but does not dissolve existing clot. Endogenous fibrinolysis and clot

resolution typically occurs over weeks to months, but may be

incomplete. Short-term therapy with unfractionated heparin

(5,000 unit or 80 IU/kg bolus, followed by a nomogramadjusted infusion), low-molecular-weight heparins (enoxaparin, dalteparin, etc.), or fondaparinux is used as a bridge to

long-term therapy with a vitamin K antagonist such as warfarin. The target international normalized ratio for warfarin

administration is 2.0-3.0. Length of treatment may be limited to 3 months if a clear precipitant (transient or reversible)

is identified, but otherwise long-term treatment is recommended as long as the benefits outweigh the risks. Newer

medications such as direct thrombin inhibitors are promising

alternatives to warfarin, but are still being studied. An inferior vena cava filter is indicated in patients with contraindications to anticoagulation ( eg, active gastrointestinal

bleeding) or who have failed anticoagulant therapy.

PULMONARY EMBOLISM

Suspect PE: dyspnea, pleuritic chest pain or

tachypnea, andjor risk factors

Negative

Hemodynamically

unstable: Consider

thrombolytics

Figure 25-2. Pulmonary embolism diagnostic algorithm. CTA, computed tomography angiography; IVC, intravenous

catheter; LE, lower extremity; PE, pulmonary embol ism; VQ, venti lation/perfusion .

Thrombolytic agents that directly lyse the clot are indicated in hemodynamically unstable patients with con ­

firmed PE, when the benefits of treatment outweigh the

risks of life-threatening bleeding complications ( 1 3% risk

of major hemorrhage) .