What is the immediate treatment protocol for a patient diagnosed with pulmonary embolism?

Immediate Treatment Protocol for Pulmonary Embolism

Initiate anticoagulation with intravenous unfractionated heparin immediately upon suspecting pulmonary embolism, without waiting for diagnostic confirmation, unless the patient has active bleeding or absolute contraindications. 1, 2

Initial Assessment and Hemodynamic Stratification

Perform bedside transthoracic echocardiography immediately in any patient presenting with hemodynamic instability (hypotension, shock, or collapse) to differentiate high-risk PE from other life-threatening conditions like cardiac tamponade or acute myocardial infarction. 1, 2

Clinical Features Suggesting PE:

• Sudden collapse with elevated jugular venous pressure 1, 2
• Isolated dyspnea without cough, sputum, or chest pain 1, 2
• Pleuritic chest pain and/or hemoptysis 1
• Tachypnea (respiratory rate >20/min) in most cases 1

Risk stratify all patients immediately into high-risk (hemodynamically unstable) versus intermediate/low-risk (hemodynamically stable) categories, as this determines the entire treatment pathway. 1

Immediate Anticoagulation Protocol

For High-Risk PE (Hemodynamically Unstable):

Administer weight-adjusted intravenous unfractionated heparin with an 80 IU/kg bolus followed by 18 IU/kg/hour continuous infusion. 1, 2 Alternatively, use standard dosing of 5,000-10,000 IU bolus followed by 1,300 IU/hour. 1, 2

• Monitor APTT after 4-6 hours and adjust infusion to maintain APTT at 1.5-2.5 times control (45-75 seconds) 1, 2
• Recheck APTT 6-10 hours after any dose adjustment 1
• Once therapeutic, monitor APTT daily 1

For Intermediate/Low-Risk PE (Hemodynamically Stable):

Prefer low-molecular-weight heparin (LMWH) or fondaparinux over unfractionated heparin for most hemodynamically stable patients. 1 This avoids the need for continuous monitoring and has more predictable pharmacokinetics. 3, 4

When initiating oral anticoagulation, use a direct oral anticoagulant (NOAC) such as rivaroxaban, apixaban, dabigatran, or edoxaban in preference to warfarin. 1, 5

Reperfusion Therapy for High-Risk PE

Administer systemic thrombolytic therapy immediately for all patients with high-risk PE (hemodynamic instability). 1

Thrombolytic Regimen Options:

• rtPA: 100 mg over 2 hours 1
• Streptokinase: 250,000 units over 20 minutes, then 100,000 units/hour for 24 hours (with hydrocortisone to prevent circulatory instability) 1
• Urokinase: 4,400 IU/kg over 10 minutes, then 4,400 IU/kg/hour for 12 hours 1

Stop heparin before initiating thrombolysis, then resume at maintenance dose after completion. 1, 2

Alternative Reperfusion When Thrombolysis Contraindicated or Failed:

Perform surgical pulmonary embolectomy for patients with high-risk PE when thrombolysis is contraindicated or has failed. 1

Consider percutaneous catheter-directed treatment as an alternative to surgery in centers with expertise. 1

Hemodynamic Support

Administer norepinephrine and/or dobutamine for hemodynamic support in high-risk PE. 1, 6

Avoid aggressive fluid challenges, as they worsen right ventricular failure by increasing preload. 6, 7 Consider gentle diuresis or preload reduction instead. 7

Administer supplemental oxygen to maintain SaO2 >90%, escalating from nasal cannula to high-flow oxygen to non-invasive ventilation as needed. 6

Rescue Therapy for Deterioration

Administer rescue thrombolytic therapy immediately if a patient on anticoagulation develops hemodynamic deterioration. 1

Consider surgical embolectomy or catheter-directed treatment as alternatives to rescue thrombolysis if contraindications exist. 1

Transition to Oral Anticoagulation

For Patients Started on Parenteral Anticoagulation:

When using a NOAC, rivaroxaban (15 mg twice daily for 21 days, then 20 mg once daily) or apixaban can be started immediately without parenteral overlap. 8 For dabigatran or edoxaban, continue parenteral anticoagulation for at least 5 days before transitioning. 1

If using warfarin, overlap with parenteral anticoagulation until INR reaches 2.0-3.0 (target 2.5) for at least 24 hours, typically requiring 5 days of overlap. 1

• Check INR initially every 1-2 days 1
• Discontinue heparin only after INR ≥2.0 for at least 24 hours and minimum 5 days of heparin 1

Critical Contraindications to NOACs

Do not use NOACs in patients with severe renal impairment (CrCl <15-30 mL/min depending on agent), antiphospholipid antibody syndrome, pregnancy, or lactation. 1, 5, 8 Use warfarin with parenteral overlap instead. 1

Special Considerations

Consider inferior vena cava filter placement only in patients with absolute contraindications to anticoagulation or recurrent PE despite therapeutic anticoagulation. 1 Routine filter use is not recommended. 1

For carefully selected low-risk patients, consider early discharge (within 24-48 hours) with continuation of anticoagulation at home. 1, 5

Common Pitfalls to Avoid

• Never delay anticoagulation while awaiting diagnostic confirmation in patients with intermediate or high clinical probability of PE. 1, 2, 5 The risk of withholding treatment exceeds the bleeding risk in most cases.
• Do not miss PE in elderly patients or those with severe cardiorespiratory disease, where symptoms may be subtle. 1, 2
• Avoid using NOACs in antiphospholipid syndrome, as they are associated with increased thrombotic events compared to warfarin. 1, 5
• Do not perform neuraxial anesthesia or spinal puncture within 24 hours of LMWH administration due to spinal hematoma risk. 1, 8
• Avoid routine thrombolysis in intermediate-risk PE without hemodynamic deterioration, as bleeding risks outweigh benefits. 1