Pulmonary embolism

Pulmonary embolism - Acute
Rahul Soman, M. Pharm

 

Definition  

A common, serious, and potentially fatal complication of DVT and encompasses pulmonary hemorrhage or infarction, isolated dyspnea (pulmonary embolism not complicated by pulmonary hemorrhage, infarction, or circulatory collapse), and circulatory collapse or shock . A massive pulmonary embolism (PE) is the sudden occurrence of an embolus producing severe cardiovascular decompensation and usually refers to more than 50% obstruction of the pulmonary artery diameter .

 

Medical History  

* Deep venous thrombosis [Deep venous thrombosis - Acute]

* Impaired mobility

* Traumatic injury

* Neoplastic disease

* Thrombophilia

* Obesity

* Central venous cannula insertion

* Prolonged Immobilization with Travel

* Esterified Estrogens use

* Progesterone/Esterified Estrogens use

* Pregnancy

 

Findings  

* Dyspnea - Acute

* Chest pain, acute

* Tachypnea

* Increased heart rate

* Cough

* Hypotension

* Fever

* Abnormal breath sounds

* Heart sounds abnormal

* Pain in limb

* Diaphoresis

* Edema - Acute

* Cyanosis

* Syncope and collapse

* Hemoptysis - Acute

* Altered mental status

* Seizure

* Abdominal pain, acute

 

Tests  

 

Suspected pulmonary embolism  

* 12 lead ECG: ST segment depression and T wave inversion are the most common ECG manifestations of pulmonary embolism but are nonspecific and transient .

 

Suspected pulmonary embolism  

* Plain chest X-ray: A normal chest x-ray supports the diagnosis of pulmonary embolism, and other findings may make an alternative diagnosis .

 

Suspected pulmonary embolism  

* D-dimer assay: In appropriately selected patients with a low pretest probability of pulmonary embolism (PE), a normal high-sensitivity D-dimer indicates a low likelihood of PE .

 

Suspected pulmonary embolism  

* CT angiography of pulmonary artery: A normal CT angiogram (alone or combined with CT venography) reliably excludes clinically significant PE in patients with a low or moderate probability clinical assessment .

 

Suspected deep vein thrombosis in patients evaluated for pulmonary embolism  

* Computed tomography venography: Use of CT venography after CT angiography improves diagnostic accuracy of PE and is recommended as the first imaging tests .

 

Suspected deep vein thrombosis in patients evaluated for pulmonary embolism  

* Ultrasonography for deep vein thrombosis: Venous ultrasound can help exclude a significant pulmonary embolism in patients with a low or moderate probability clinical assessment .

 

Suspected pulmonary embolism  

* VQ - Ventilation perfusion scan: A normal ventilation perfusion scan in patients with a clinical probability below 20% essentially excludes the diagnosis of pulmonary embolism .

 

Suspected deep vein thrombosis in patients evaluated for pulmonary embolism  

* MRI venography: Magnetic resonance venography is an option for further testing to detect or exclude concurrent DVT when CT venography was not performed after CT angiography .

 

Differential Diagnosis  

* Acute coronary syndrome

* Aortic dissection - Acute

* Pneumothorax - Acute

* Pneumonia

* Bronchitis, acute - Acute

* Pericarditis - Acute

* Pulmonary edema - Acute

* Asthma - Acute

* Costal chondritis

* Cardiac tamponade - Acute

* Lung cancer

* Aspiration pneumonia - Acute

* Esophageal perforation - Acute

* Fat embolism - Acute

* Pulmonary hypertension

* Fracture of rib

* Hyperventilation - Acute

 

Treatment  

 

Drug Therapy  

 

 

Initial therapy for patients with high clinical suspicion of or objectively confirmed acute pulmonary embolism  

 

ENOXAPARIN SODIUM - WARFARIN SODIUM  

Adults: Enoxaparin sodium 1 mg/kg subQ every 12 hours or 1.5 mg/kg every 24 hours AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue enoxaparin sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

 

HEPARIN SODIUM - WARFARIN SODIUM  

Adults (IV dosing): Initial heparin sodium IV bolus of 80 units/kg or 5000 units, then 18 units/kg/hr or 1300 units/hr continuous infusion with dose adjustments to achieve and maintain an activated partial thromboplastin time (aPTT) prolongation that corresponds to plasma heparin levels of 0.3 to 0.7 international units/mL anti-Xa activity by the amidolytic assay AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue heparin sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

Adults (monitored subQ dosing): Initial heparin sodium subQ dose of 17,500 units or 250 units/kg twice daily, with dose adjustments to achieve and maintain an aPTT prolongation corresponding to plasma heparin levels of 0.3 to 0.7 international units/mL anti-Xa activity when measured 6 hours after injection AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue heparin sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

Adults (fixed-dose unmonitored subQ dosing): Initial heparin sodium subQ dose of 333 units/kg followed by 250 units/kg twice daily AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue heparin sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

 

FONDAPARINUX SODIUM - WARFARIN SODIUM  

Adults (over 100 kg): Fondaparinux sodium 10 mg subQ once daily for 5 to 9 days AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue fondaparinux sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

Adults (50 to 100 kg): Fondaparinux sodium 7.5 mg subQ once daily for 5 to 9 days AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue fondaparinux sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

Adults (below 50 kg): Fondaparinux sodium 5 mg subQ once daily for 5 to 9 days AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue fondaparinux sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

 

TINZAPARIN SODIUM - WARFARIN SODIUM  

Adults: Tinzaparin sodium 175 units/kg subQ once daily for at least 6 days AND warfarin sodium 5 mg to 10 mg for the first 1 to 2 days; adjust subsequent dosing based on the INR response ; continue tinzaparin sodium for at least 5 days and until the INR is greater than or equal to 2 for at least 24 hours

 

 

Long-term prophylaxis or treatment of pulmonary embolism  

 

WARFARIN SODIUM  

Adults: 2.5 to 10 mg/day orally for 1 to 3 days, then adjust daily dose to maintain an INR at 2.5 (range 2 to 3)

 

 

Hemodynamically unstable patients with pulmonary embolism  

 

ALTEPLASE, RECOMBINANT  

Adults: 100 mg via continuous peripheral IV infusion over 2 hours

 

STREPTOKINASE  

Adults: 250,000 international units IV bolus over 30 minutes, then 100,000 international units/hr IV for 24 hours (72 hours if concurrent DVT suspected) .

 

 

Treatment of acute venous thromboembolism during pregnancy  

 

DALTEPARIN SODIUM  

Adults (initial therapy): 200 units/kg subQ daily or 100 units/kg subQ twice daily for at least 5 days; continue heparin throughout pregnancy; discontinue heparin at least 24 hours prior to induction of labor or elective cesarean section

 

TINZAPARIN SODIUM  

Adults (initial therapy): 175 units/kg subQ daily for at least 5 days; continue throughout pregnancy; discontinue heparin at least 24 hours prior to induction of labor or elective cesarean section

 

ENOXAPARIN SODIUM  

Adults (initial therapy): 1 mg/kg subQ every 12 hours for at least 5 days; continue heparin throughout pregnancy; discontinue heparin at least 24 hours prior to induction of labor or elective cesarean section

 

HEPARIN SODIUM  

Adults (initial therapy): IV bolus, followed by a continuous infusion to maintain the aPTT within the therapeutic range OR subQ therapy adjusted to maintain the aPTT 6 hours after injection into the therapeutic aPTT range for at least 5 days; discontinue heparin at least 24 hours prior to induction of labor or elective cesarean section; discontinue heparin in women with a high risk of recurrent VTE 4 to 6 hours prior to time of anticipated delivery

 

Procedural Therapy  

 

Acute circulatory failure caused by acute massive pulmonary embolism  

* Intravenous fluid replacement: Volume loading may improve the hemodynamic status ; some experts recommend that the volume should not exceed 500 mL but controlled human studies are lacking .

 

Pulmonary embolism  

* Arterial embolectomy: Emergency pulmonary embolectomy may be used in selected highly compromised acute pulmonary embolism patients when more conservative measures are contraindicated or have failed .

 

Prevention of pulmonary embolism in high risk patients with contraindications to or complications from anticoagulation or with recurrent thromboembolism despite adequate anticoagulation  

* Vena cava filter insertion: Vena cava filter placement may be used to prevent clinically significant pulmonary embolism when anticoagulant treatment or prophylaxis of proximal DVT is contraindicated or ineffective .