Pulmonary Embolism: Recognize and Act

Medical-Surgical · Respiratory / Pulmonology·Updated 2026-10-28

What it is

A pulmonary embolism (PE) is a blockage of a pulmonary artery, most often by a thrombus that breaks off from a deep vein thrombosis (DVT) in the leg or pelvis. Alveoli that are still ventilated lose their blood flow, so ventilation-perfusion mismatch causes hypoxemia and the client hyperventilates; a large clot strains the right ventricle and causes obstructive shock. Nursing care centers on oxygenation, anticoagulation to stop clot growth, and prevention of further DVT.

What the NCLEX focuses on

Risk factors (Virchow triad of stasis, vessel injury and hypercoagulability): immobility, recent surgery (especially hip or knee), long travel, cancer, pregnancy and postpartum, estrogen therapy, previous DVT, obesity and smoking.
Findings: sudden dyspnea and tachypnea (most common), pleuritic chest pain, tachycardia, anxiety, cough, hemoptysis, crackles and falling SpO2; a massive PE adds hypotension, jugular venous distention and syncope.
Early ABG: hypoxemia with respiratory alkalosis (low PaCO2) from hyperventilation.
CT pulmonary angiography is the diagnostic test of choice; a negative D-dimer helps rule out PE, but a positive D-dimer is not specific.
Unfractionated heparin is monitored by aPTT or anti-Xa level; protamine sulfate reverses it; a platelet fall of 50% or more suggests heparin-induced thrombocytopenia.
Warfarin overlaps with heparin for at least 5 days until the INR is 2 to 3; vitamin K reverses it.
Alteplase is reserved for PE with persistent hypotension; a history of intracranial hemorrhage, ischemic stroke within 3 months or active internal bleeding is an absolute contraindication.

Priority nursing actions

Stay with the client, raise the head of the bed and call the rapid response team.
Apply oxygen and assess respiratory rate, SpO2, lung sounds, heart rate and blood pressure.
Establish IV access, obtain prescribed labs (ABG, CBC, aPTT, D-dimer) and prepare for CT pulmonary angiography.
Start the prescribed weight-based heparin infusion with an independent double check.
Monitor for bleeding; for new flank or back pain, hypotension or a falling hemoglobin, stop the infusion per protocol and notify the provider.
If hypotension persists, prepare for fibrinolytic therapy or embolectomy.

Numbers to know

Value	Normal or target	Why it matters
PaCO2	35 to 45 mm Hg (4.7 to 6.0 kPa)	Low early in PE from hyperventilation
PaO2	80 to 100 mm Hg (10.7 to 13.3 kPa)	Low from ventilation-perfusion mismatch
aPTT on heparin	1.5 to 2.5 times control, or the facility range	Above range raises bleeding risk; hold and report
INR on warfarin	2 to 3	Therapeutic range for venous thromboembolism
Platelets	150,000 to 400,000/mm3 (150 to 400 x 10^9/L)	A 50% fall on heparin signals heparin-induced thrombocytopenia
Anticoagulation length	At least 3 months	Standard course after a provoked PE

Common exam traps

Choosing to send the client for CT before applying oxygen: wrong because hypoxemia is treated first and the client is never left unmonitored.
Choosing to continue heparin while investigating flank pain, hypotension and a falling hemoglobin: wrong because these signal major bleeding; stop the infusion per protocol first.
Choosing protamine for a client on warfarin with a high INR: wrong because protamine reverses heparin; vitamin K reverses warfarin.
Choosing to prepare alteplase for a client with a previous hemorrhagic stroke: wrong because that is an absolute contraindication; stop and clarify.
Choosing to massage a painful, swollen calf: wrong because it can dislodge the thrombus.

What to teach

Take the anticoagulant at the same time every day, never double a missed dose, and keep INR appointments if taking warfarin.
Use a soft toothbrush and electric razor; avoid aspirin and NSAIDs unless prescribed; report black stools, pink urine, bleeding gums or severe headache.
Walk often, do ankle pumps on long trips, stay hydrated and avoid crossing the legs.
Call 911 for sudden shortness of breath, chest pain or coughing up blood.

Client handout: Preventing Blood Clots (DVT) (nurse guide and printable patient handout).

Try 2 NCLEX-style questions on this topic

From the NCLEXPace question bank. Pick your answers, then check them inside NCLEXPace.

Question 1 · QID E4E2C34E

A client receiving a weight-based IV heparin infusion for pulmonary embolism develops new severe flank pain, BP 86/50 mm Hg, and a decreasing hemoglobin level. Which action should the nurse take first?

Select the best answer.

A. Obtain a stat anticoagulation level and repeat hemoglobin, then continue the heparin infusion until laboratory results confirm active bleeding
B. Stop or hold the infusion according to the high-alert medication protocol, assess the client, and notify the provider immediately
C. Continue the current heparin rate while obtaining urgent imaging for possible recurrent thromboembolism
D. Stop the infusion temporarily and obtain repeat blood pressure and hemoglobin before notifying the provider

Question 2 · QID C5E8C91B

The emergency team considers systemic alteplase for a client with pulmonary embolism and persistent hypotension. Which finding requires the nurse to stop preparation and immediately clarify the prescription?

Select the best answer.

A. Platelet count 118,000/mm3 with no evidence of active bleeding
B. A history of hemorrhagic stroke
C. Recent cardiopulmonary resuscitation with brief chest compressions and no traumatic injury
D. A gastrointestinal ulcer treated medically 8 months ago with no recent bleeding

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Sources

Harding MM, Kwong J, Hagler D, Reinisch C. Lewis's Medical-Surgical Nursing: Assessment and Management of Clinical Problems. 12th ed. Elsevier; 2023; Chapter: Lower Respiratory Problems.
Harding MM, Kwong J, Hagler D, Reinisch C. Lewis's Medical-Surgical Nursing: Assessment and Management of Clinical Problems. 12th ed. Elsevier; 2023; Chapter: Vascular Disorders.
Stevens SM, et al. Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report. Chest. 2021;160(6):e545-e608.

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