Pulmonary embolism treatment algorithm

Associate Editors-in-Chief: Ujjwal Rastogi, MBBS [mailto:urastogi@perfuse.org]

Overview
Pulmonary embolism (PE) is a potentially lethal condition, with a mortality rate close to 30 percent without treatment. Thus prompt and effective therapy is of utmost important. In most cases, anticoagulant therapy is the mainstay of treatment. Acutely, supportive treatments, such as oxygen or analgesia, are often required.

Initial Treatment
Depending on the clinical presentation, initial therapy is primarily aimed:
 * 1) Restoration of ﬂow through occluded pulmonary arteries.
 * 2) Prevention of potentially fatal early recurrences.

Most common reason for mortality is recurrent PE, occurring within the few hours of the initial event. Anticoagulant therapy decreases mortality by 2% to 8%, thus making it absolutely necessary to start therapy as soon as possible.

Majority of patient should be started on anticoagulation, with one of the following drugs :
 * Subcutaneous Low molecular weight heparin
 * Intravenous unfractionated heparin.
 * Factor Xa Inhibitors (Fondaparinux).

==Treatment Protocol ==

Respiratory Support
 * Oxygen should be used in hypoxemic patients.
 * In cases of severe hypoxemia or respiratory failure, mechanical ventilation and intubation should be started.

Hemodynamic Support
 * Intravenous fluid administration is first-line therapy in hypotensive patients.
 * IV Fluid should be administered cautiously, as increase Right ventricular load can disable Right ventricular oxygen supply-to-demand balance.
 * If the hemodynamic status fails to improve, then intravenous vasopressors should be considered.

Extended Treatment should be considered in patients with:
 * 1) Active Cancer.
 * 2) Unprovoked Pulmonary embolism.
 * 3) Recurrent venous thromboembolism.

Indefinite treatment refers to continued anticoagulation without a pre-scheduled stop date. Anticoaulation is stopped because of:
 * 1) Risk of bleeding.
 * 2) Change in patients preference.

Treatment of Choice:Special Considerations

 * Subcutaneous or Intravenous Low molecular weight heparin.
 * Hemodynamically stable patients.
 * Thrombolysis
 * High Risk Hemodynamically stable patients.
 * Hemodynamically Unstable patients.
 * Percutaneous mechanical thrombectomy.
 * High risk patients with absolute contraindications to Thrombolytics.
 * Patients with failed Thrombolysis.
 * Low molecular weight heparin is preferred over Vitamin K antagonist.
 * Cancer patients.
 * Pregnant patients.