What is the appropriate workup and treatment for a patient with suspected pulmonary embolism?

Pulmonary Embolism Workup and Treatment

Begin immediate anticoagulation with intravenous heparin as soon as pulmonary embolism is suspected—do not wait for diagnostic confirmation—while simultaneously pursuing risk stratification and imaging. 1, 2

Initial Clinical Assessment

Recognize Classic Presentations

Look for three specific clinical patterns that should trigger immediate PE evaluation: 3, 1

• Sudden collapse with elevated jugular venous pressure (faintness and/or hypotension) 3
• Pulmonary hemorrhage syndrome (pleuritic pain and/or hemoptysis) 3
• Isolated dyspnea without cough, sputum, or chest pain 3, 1

High-Risk Populations Where PE is Easily Missed

Pay particular attention to: 3, 2

• Elderly patients—PE is frequently misdiagnosed in this population, especially when isolated dyspnea is the only symptom 3, 2
• Patients with severe pre-existing cardiorespiratory disease 3
• Most patients will present with breathlessness and/or tachypnea (respiratory rate >20/min) 3, 1

Risk Factor Assessment

Score clinical probability using major risk factors (score +1 if present): 3

• Recent immobilization or major surgery 3
• Recent lower limb trauma and/or surgery 3
• Clinical deep vein thrombosis 3
• Previous proven DVT or PE 3
• Pregnancy or post-partum 3
• Major medical illness 3

Note: PE is rare in patients under age 40 without risk factors 3

Immediate Management Based on Hemodynamic Status

For Hemodynamically Unstable Patients (Shock/Hypotension)

Perform bedside transthoracic echocardiography immediately to differentiate high-risk PE from other acute life-threatening conditions. 1, 2

Initiate systemic thrombolysis immediately with one of the following regimens (stop heparin before thrombolysis, resume at maintenance dose after): 3, 1, 2

• rtPA: 100 mg over 2 hours 3, 2
• Streptokinase: 250,000 units over 20 minutes, then 100,000 units/hour for 24 hours (plus hydrocortisone to prevent circulatory instability) 3, 2
• Urokinase: 4,400 IU/kg over 10 minutes, then 4,400 IU/kg/hour for 12 hours 3, 2

For Hemodynamically Stable Patients

Start weight-adjusted IV heparin immediately without waiting for diagnostic confirmation: 1, 2

Weight-adjusted dosing (preferred): 3, 1, 2

• Initial bolus: 80 IU/kg IV 1, 2
• Maintenance infusion: 18 IU/kg/hour 1, 2

Standard dosing (alternative): 3, 1

• Initial bolus: 5,000-10,000 IU IV 3, 1
• Maintenance infusion: 1,300 IU/hour 3, 1

Target aPTT: 1.5-2.5 times control (45-75 seconds) 3, 1

Monitoring Protocol

aPTT Monitoring Schedule

3, 1

• First check: 4-6 hours after initial bolus 3
• After any dose change: 6-10 hours later 3
• Once therapeutic: Daily 3

Transition to Oral Anticoagulation

Warfarin Protocol

Start warfarin simultaneously with heparin—do not wait. 2

Initial dosing: 5-10 mg daily for 2 days 3, 1, 2

Subsequent dosing: Adjust to maintain INR 2.0-3.0, measured every 1-2 days initially 3, 1

Discontinue heparin: After at least 5 days AND when INR ≥2.0 for at least 24 hours 3, 2

Direct Oral Anticoagulants (DOACs)

For treatment of acute PE, consider: 4, 5

Apixaban: 4

• 10 mg orally twice daily for 7 days 4
• Then 5 mg twice daily 4
• For recurrence prevention after ≥6 months treatment: 2.5 mg twice daily 4

Rivaroxaban: 5

• 15 mg orally twice daily for 21 days with food 5
• Then 20 mg once daily with food 5

Important: When switching from warfarin to a DOAC, discontinue warfarin and start the DOAC when INR <2.0. 4

Duration of Anticoagulation

6, 2

• First episode with temporary risk factors: 3-6 months 6, 2
• Idiopathic or recurrent PE: Consider indefinite anticoagulation 6, 2
• Minimum duration: 3 months 6

Supportive Measures

1, 2

• Administer oxygen to maintain adequate saturation 1, 2
• Consider diuretics for pulmonary congestion and volume overload 1, 2
• Avoid beta-blockers or calcium channel blockers in patients with frank cardiac failure 1, 2

Special Considerations

Contraindications to Anticoagulation

Consider inferior vena cava filter placement only if anticoagulation is absolutely contraindicated. 1, 2

Surgery/Procedures

Discontinue anticoagulation: 4

• 48 hours prior for moderate/high bleeding risk procedures 4
• 24 hours prior for low bleeding risk procedures 4

Critical Pitfalls to Avoid

1, 2

• Never delay anticoagulation while waiting for diagnostic confirmation—start treatment as soon as PE is suspected 1, 2
• Never discontinue heparin prematurely before achieving adequate oral anticoagulation (INR ≥2.0 for at least 24 hours) 2
• Never underestimate symptoms in elderly patients—PE is easily misdiagnosed when presenting with isolated dyspnea 3, 2
• Never assume PE is ruled out in patients with severe cardiorespiratory disease where symptoms may be attributed to underlying conditions 3

Discharge Checklist

Before discharge, ensure: 3

• INR is between 2.0-3.0 3
• General practitioner is aware of anticoagulation and proposed duration 3
• Patient understands side effects, drug interactions, and has written information 3
• Follow-up arranged at 6-12 weeks to reassess duration and screen for thrombophilic disorders or occult malignancy if idiopathic 3