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Respiratory

Pulmonary Embolism

PE High-yield Verified · Sep 2026

A pulmonary embolism is a sudden blockage of a pulmonary artery, most often by a blood clot that formed in a deep vein of the leg, broke free, and traveled through the bloodstream to the lungs.

The classic "sudden change" emergency: dead-space physiology explains why the lungs sound clear, the right ventricle decides who dies, and untreated mortality of up to 30% falls to roughly 8% with timely therapy — recognition is the intervention.

What’s going wrong in the body

The normal physiology, where it fails, and why the body’s compensation backfires.

01 A clot that traveled

A PE almost never starts in the lungs. It most commonly begins as a deep vein thrombosis (DVT) of the lower extremities — one study found DVT in 70% of patients with proven PE. A piece of that thrombus breaks off, rides the venous return through the right side of the heart, and wedges wherever the branching pulmonary arteries become too narrow to pass. Everything that produces the clot maps onto Virchow’s triad: venous stasis (immobility, long travel), hypercoagulability (cancer, estrogen, inherited thrombophilias), and endothelial injury (surgery, trauma).

Rarely the embolus isn’t a clot at all: air, fat, or tumor cells can obstruct the pulmonary circulation the same way.

The embolization path: a leg-vein thrombus fragments, crosses the right heart, and occludes a pulmonary artery — air still arrives, blood no longer does.

02 Ventilated but not perfused — why the lungs sound clear

The occluded segment still receives air with every breath, but its capillary blood flow has stopped: alveolar ventilation continues while perfusion falls. That is dead-space ventilation — wasted breaths — and the resulting V/Q mismatch produces hypoxemia. Because the alveoli themselves are open and dry, auscultation is often unremarkable: unexplained hypoxemia with a normal chest exam and a normal chest radiograph should raise suspicion for PE. This is the single most useful bedside hook, and it is exactly why PE gets mistaken for anxiety.

The hypoxemic patient breathes fast, blowing off CO₂ — so the early ABG shows hypoxemia with respiratory alkalosis and hypocapnia, a widened A–a gradient. Acidosis is the ominous exception, seen when massive PE has already produced shock. Blood gases can never rule PE out.

03 The right ventricle takes the hit

Small emboli irritate the pleura and infarct lung tissue — pleuritic pain, cough, hemoptysis — but they don’t kill. Large ones do, and the mechanism is cardiac, not respiratory: once thromboembolic occlusion exceeds 30–50% of the cross-sectional area of the pulmonary arterial bed, pulmonary artery pressure climbs. Rising pulmonary vascular resistance raises right-ventricular afterload, impedes RV outflow, and dilates the thin-walled right ventricle.

Acute RV failure from pressure overload is the primary cause of death in severe PE. When the strained RV can no longer push blood through the obstructed lungs, output to the left heart collapses — obstructive shock. The 2019 ESC scheme (as tabulated in J Clin Med 2024) defines this high-risk (massive) PE as hemodynamic instability: cardiac arrest, obstructive shock (SBP < 90 mmHg or vasopressors needed, with end-organ hypoperfusion), or persistent hypotension (SBP < 90 mmHg or a drop ≥ 40 mmHg for > 15 minutes). These patients get thrombolytics, not just anticoagulation.

The lethal cascade: enough occlusion raises RV afterload until the right ventricle fails — the patient dies of an obstructed circulation, not of hypoxemia.

04 From suspicion to certainty — and how dangerous is this one?

Presentation is very nonspecific — in PIOPED data dyspnea occurred in 73% and pleuritic pain in 66%, but a real-world cohort ran far lower and 10.8% of confirmed PEs were asymptomatic. So diagnosis runs on structured probability. The Wells score sets pretest probability; if PE is unlikely (≤ 4), a quantitative D-dimer below 500 ng/mL — sensitivity ≥ 95% — safely excludes PE with no imaging. If PE is likely (> 4), skip the D-dimer (it can only rule out, never in) and go straight to CT pulmonary angiography, the diagnostic modality of choice.

Confirmed PE is then risk-stratified, because treatment intensity follows it (2019 ESC, as reported in J Clin Med 2024): high risk = hemodynamic instability; among stable patients with PESI III–IV or sPESI ≥ 1, intermediate-high = both RV dysfunction on imaging and a positive biomarker, intermediate-low = one or neither (together, the old "submassive" group); low risk = PESI I–II or sPESI 0, with a 30-day mortality around 1% — versus about 11% when sPESI ≥ 1. About 30% of PEs are unprovoked — no identifiable trigger — and an unprovoked PE is one of the reasons anticoagulation is extended beyond 3 months.

The rule-out logic: low/intermediate probability earns a D-dimer; a negative result ends the workup, anything else goes to CTPA.

Causes & risk factors

Modifiable factors are teaching targets — the patient can act on them.

Prolonged immobility — bed rest > 3 days; any travel > 4 hours modifiable Recent surgery — most commonly orthopedic (hip/knee replacement), also abdominal and brain Lower-limb fracture & major trauma Active cancer — highest risk: pancreatic, hematologic, lung, gastric, brain; highest when metastatic Prior DVT or PE — recurrence risk is high; unprovoked events recur at 2–3× the rate Obesity modifiable Cigarette smoking modifiable Estrogen — oral contraceptives, hormone replacement therapy modifiable Pregnancy & the postpartum period Indwelling venous catheter Heart failure, acute infection, chemotherapy Inherited thrombophilias — factor V Leiden, prothrombin gene mutation, protein C or S deficiency, hyperhomocysteinemia Hospitalization itself — hospitalized patients are at sharply increased DVT risk, yet reportedly only about half receive prophylaxis

Signs & symptoms

Each finding tied to the mechanism that produces it — and the triage it calls for.

Sudden-onset dyspnea Report immediately
Why: Dead-space ventilation and V/Q mismatch drop oxygenation abruptly — the most common symptom (73% in PIOPED). Acute and severe in central PE; may be mild and transient with a small peripheral embolus.
Pleuritic chest pain — sharp, stabbing, worse with each deep breath Hold & notify
Why: Distal emboli infarct lung tissue against the pleura; the inflamed pleura hurts with every inspiratory stretch.
Tachypnea & tachycardia Hold & notify
Why: Hypoxemia drives respiratory rate up while the heart races to push output past an obstructed pulmonary bed — common but nonspecific, so they’re easy to explain away.
Hypoxemia with clear lung sounds and a normal chest film Report immediately
Why: The alveoli are open and dry — the problem is perfusion, not ventilation. Unexplained hypoxemia with a normal chest exam should raise suspicion for PE, not lower it.
Sudden anxiety — a sense of "impending doom" Hold & notify
Why: Named in the classic sign list alongside dyspnea and chest pain. In a patient with VTE risk factors, new unexplained anxiety plus breathlessness is a cue to assess and escalate — never to reassure and walk away.
Cough Expected
Why: Airway and pleural irritation from the infarcting segment — present in roughly a third of patients (37% in PIOPED).
Hemoptysis — coughing up blood Hold & notify
Why: Pulmonary infarction bleeds into the airways. Only ~13% of patients have it — which is why the "classic triad" of dyspnea + pleuritic pain + hemoptysis is necessarily uncommon in real patients.
Presyncope or syncope Report immediately
Why: A transient collapse of left-heart filling. Syncope with PE is associated with higher rates of hemodynamic instability and RV dysfunction — treat it as a marker of a big clot.
Unilateral calf swelling, tenderness, erythema, or a palpable cord Hold & notify
Why: The concurrent DVT that launched the embolus — found in most proven PEs. One swollen leg plus new dyspnea is the pattern to connect.
JVD, parasternal lift, a third heart sound, cyanosis, falling BP late Report immediately
Why: The acute RV-failure picture of massive PE — the right heart is losing against the obstructed pulmonary bed. PE is reportedly behind roughly 8% of sudden cardiac arrests.
Little or nothing at all
Why: Presentation is very nonspecific: 10.8% of confirmed PEs in one cohort were asymptomatic, and even large PEs can be mildly symptomatic. Risk factors plus any sudden change deserve a workup.

Diagnostics

Test In this disorder Normal
Wells score (pretest probability) Heaviest weights: clinical signs of DVT (3) and "alternative diagnosis less likely than PE" (3); HR > 100, recent immobilization/surgery, and prior VTE score 1.5 each Two-tier: PE likely > 4 → straight to CTPA · PE unlikely ≤ 4 → D-dimer first. Three-tier: high > 6, moderate 2–6, low < 2 StatPearls —
D-dimer (quantitative ELISA) Rules out, never in — falsely elevated in pregnancy, cancer, trauma, infection, and age (specificity ~10% over 80). Age-adjusted cutoff for age > 50: age × 10 ng/mL. High pretest probability skips the D-dimer entirely ≥ 500 ng/mL is positive; < 500 ng/mL excludes PE when pretest probability is low/intermediate (sensitivity ≥ 95%) StatPearls < 500 ng/mL
CT pulmonary angiography (CTPA) Needs IV contrast — check renal function and contrast allergy; a V/Q scan replaces it when CTPA is contraindicated and is the test of choice in pregnancy with a normal chest film (a normal scan excludes PE) The primary diagnostic modality of choice — visualizes clot down to subsegmental arteries; sensitivity 83%, specificity 96% PIOPED II —
ABG Acidosis is ominous — seen in massive PE with shock. Blood gases can never rule PE out Hypoxemia + respiratory alkalosis with hypocapnia early (the tachypneic patient blowing off CO₂); widened A–a gradient —
ECG S1Q3T3 is the classic-but-unreliable finding — neither sensitive nor specific; don’t wait for it Sinus tachycardia and nonspecific ST/T changes are the most common findings —
Troponin I / BNP Elevated troponin plus RV dysfunction on imaging = intermediate-high risk; either one alone = intermediate-low — the intermediate-high patient earns closer monitoring for deterioration Prognostic, not diagnostic — troponin is elevated in roughly 30–50% of moderate-to-large PE and flags deterioration risk; BNP tracks RV-dysfunction severity ESC 2019 (via J Clin Med 2024) —

Complications

Warning: Obstructive shock → cardiac arrest Report immediately
Massive PE strangles left-heart filling: hypotension (SBP < 90), syncope, JVD, and new RV-failure signs herald collapse.
This is the thrombolytics scenario — systemic thrombolysis is the treatment of choice for hemodynamically unstable PE. The nurse’s part: recognize the heralds, call the rapid response, and know that aggressive IV fluids are not routine here — over-filling worsens RV overload; vasopressors may be needed instead.
Caution: Pulmonary infarction Hold & notify
Reported in 16–31% of PEs — heralded by pleuritic pain and hemoptysis as the starved lung segment dies.
Sounds dramatic but is rarely lethal (survival to discharge ~97%). Its real value is as a recognition cue: new pleuritic pain or bloody sputum in an at-risk patient means embolism until proven otherwise.
Caution: Chronic thromboembolic pulmonary hypertension (CTEPH) Hold & notify
In up to ~5% of patients the clot never fully clears; the pulmonary bed stays obstructed and pressures stay high.
The herald is persistent or progressive dyspnea after treatment — a patient who "never got better" months after their PE needs follow-up, not reassurance.
Warning: Recurrent VTE Hold & notify
Recurrence is common — unprovoked PE carries a 2- to 3-fold recurrence risk, and about half of survivors have persistent symptoms limiting capacity.
Inadequate anticoagulation is the most common reason for recurrence on therapy — which is why adherence teaching (especially with short-half-life DOACs) is a survival intervention, not paperwork.

Medications for this condition

Why each class is prescribed here — every card links to its full pharmacology page.

Anticoagulants First-line High-alert
Cardiovascular · heparin

The mainstay of PE treatment — but know what they actually do: anticoagulants stop the clot from extending and prevent new clot while the body’s own fibrinolysis clears the old one; they do not dissolve it. DOACs are preferred over warfarin for primary VTE treatment (ASH 2020); initial parenteral therapy favors LMWH or fondaparinux over unfractionated heparin (less major bleeding, less HIT), with UFH reserved for hemodynamic instability or renal impairment. Everyone gets at least 3 months — longer when the PE was unprovoked or risk factors persist. Pregnancy: LMWH (it does not cross the placenta); DOACs are contraindicated; cancer: LMWH or a DOAC such as apixaban or rivaroxaban, preferred over warfarin.

Beyond medications

  • Oxygen — indicated for saturation < 90%; usual adult target 92–96% (88–92% if at risk of hypercapnic respiratory failure).
  • Reperfusion for massive PE — systemic thrombolysis is the treatment of choice when hemodynamically unstable (best within 48 h of onset, benefit up to 14 days — at the price of more severe bleeding); catheter-directed therapy or surgical embolectomy when thrombolysis is contraindicated (e.g. prior intracranial hemorrhage, recent stroke, active bleeding) or has failed.
  • IVC filter — only for an absolute contraindication to anticoagulation or recurrent VTE despite it; retrievable filters preferred.
  • In-hospital prevention — early ambulation and time in the chair beat bed rest; intermittent pneumatic compression and graduated stockings for at-risk patients who can’t be anticoagulated (contraindicated with limb ischemia or skin breakdown). PE is one of the most common preventable causes of hospital death.
  • Travel prevention — move the legs during any long trip; properly fitted below-knee graduated compression (15–30 mmHg) plus frequent ambulation and calf exercises for long-distance travelers at risk.
  • Rehabilitation after PE — structured rehab reduces dyspnea and improves exercise capacity, mobility, and quality of life in the roughly half of survivors with persistent symptoms.

Nursing considerations

The RN-specific layer — each action paired with the reason it matters.

Assessment & monitoring
In every at-risk patient (post-op, immobile, cancer, prior VTE), treat sudden dyspnea, tachypnea, or a falling SpO₂ with clear lungs as PE until proven otherwise.
Why: Dead-space physiology keeps the lungs sounding normal — unexplained hypoxemia with a clear chest is the classic PE picture, and it is exactly the presentation that gets mislabeled "anxiety."
Watch the trend, not the snapshot: rising respiratory rate, increasing work of breathing, escalating oxygen demand, or declining mental status.
Why: These are the recognized heralds of respiratory decompensation — the trigger for rapid response activation and oxygen, before arrest, not after.
Assess the legs: unilateral swelling, tenderness, warmth, or a palpable cord.
Why: Most PEs launch from a lower-extremity DVT (found in ~70% of proven PEs) — one swollen calf turns "shortness of breath" into a different differential.
On a heparin infusion: track aPTT (target 1.5–2.2 × the patient’s baseline), platelet count, and serial hemoglobin along with HR, BP, and rhythm.
Why: aPTT proves the dose is therapeutic; a falling platelet count flags heparin-induced thrombocytopenia; a drifting hemoglobin is bleeding until proven otherwise.
Inspect skin and mucosa for petechiae, purpura, and oozing; ask about back, flank, or joint pain and dark or smoky-colored urine.
Why: Anticoagulated patients bleed where you can’t see — flank pain and smoky urine are internal-bleeding indicators, not musculoskeletal complaints.
Minimize unnecessary venipuncture and IV starts; cluster lab draws.
Why: Every puncture is a bleeding site on anticoagulation — fewer holes, fewer hematomas.
When PE is suspected (the acute phase)
Sit the patient upright (high-Fowler’s, head of bed 60–90°) and apply oxygen per protocol — then activate the rapid response. Do not leave the patient.
Why: Upright positioning maximizes chest expansion and oxygenation and needs no order; early oxygen plus rapid response is the recognized move that prevents decompensation.
Watch for the massive-PE heralds while help arrives: hypotension, syncope, JVD, new cyanosis.
Why: These mean the right ventricle is failing against the obstruction — the patient is sliding into obstructive shock, and the team needs to hear it immediately.
Anticipate the workup and first orders: stat CTPA (or V/Q scan), ABG, ECG, troponin — and anticoagulation without delay once confirmed (UFH if unstable).
Why: Untreated PE kills up to 30%; timely therapy drops that to roughly 8%. The nurse who has the patient ready for imaging and the infusion shortens the most dangerous interval.
Be cautious with IV fluids if the patient is hypotensive — aggressive volume resuscitation is not routine in massive PE.
Why: The failing RV is already overdistended; over-filling worsens RV overload. Fluids are trialed only with evidence of intravascular depletion — vasopressors may be needed instead.
If thrombolysis is ordered, screen and report contraindications: prior intracranial hemorrhage, recent ischemic stroke, active bleeding, recent brain or spinal surgery.
Why: Thrombolytics trade hemodynamic rescue for severe-bleeding risk — the absolute contraindications are the difference between a save and a catastrophe.
Patient teaching (life on anticoagulation)
Report immediately: black or bloody stools, vomiting blood, blood in the urine, a new severe headache, or any new weakness/numbness — plus nosebleeds, gum bleeding, easy bruising, heavy menses, or back/flank pain.
Why: The first list is major hemorrhage (GI, urinary, intracranial); the second is the early-warning tier. On anticoagulation, "wait and see" is the wrong plan for any of them.
Never miss doses — especially on a DOAC. Use a pill organizer, phone alarms, and a written dosing calendar; confirm understanding with teach-back.
Why: DOACs have short half-lives, so missed doses mean unprotected hours — and inadequate anticoagulation is the most common reason PEs recur on therapy.
Tell every clinician about the anticoagulant before any procedure, dental work, or new prescription.
Why: Invasive procedures and interacting drugs are the predictable bleeding setups — they’re manageable only when the team knows in advance.
Everyday bleeding precautions: brush teeth gently, avoid rectal suppositories, and watch skin for new bruising or petechiae.
Why: Mucosa and skin are the visible early-warning surfaces; small trauma that was trivial before is now a bleeding risk.
Learn the signs of DVT and PE (leg swelling/pain, sudden dyspnea, pleuritic chest pain) and continue prescribed therapy, compression stockings, and a heart-healthy lifestyle.
Why: Recurrence is common — patients who recognize the picture early are the ones who come back in time.
On any trip over ~4 hours: get up and walk, do calf exercises seated, and wear properly fitted below-knee compression stockings (15–30 mmHg) if recommended.
Why: Prolonged sitting is venous stasis — one arm of Virchow’s triad — and calf-muscle pumping is the cheapest prophylaxis there is.

How a real nurse thinks

The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.

  1. 1
    Recognize cues

    The cues that matter: sudden dyspnea and pleuritic chest pain, SpO₂ 87% (down from 95%), HR 118, RR 28, a clear chest, a swollen tender calf, new anxiety with a sense that something is wrong — in a patient two days out from hip replacement who has been mostly immobile with her SCDs off. The normal temperature and acceptable BP are the background, not the story.

  2. 2
    Analyze cues

    Sudden hypoxemia with clear lungs is the PE signature — the problem is perfusion, not ventilation, so there are no crackles to find. The swollen calf is the likely source; orthopedic surgery, immobility, and interrupted mechanical prophylaxis stack the risk. Her Wells picture is PE likely (signs of DVT, no better alternative diagnosis, HR > 100, recent surgery) — so this patient needs imaging, not a D-dimer, which surgery would falsely elevate anyway. Expect the early ABG to show hypoxemia with respiratory alkalosis from tachypnea. The "she’s just anxious" read is the trap: anxiety doesn’t drop saturation to 87%.

  3. 3
    Prioritize

    Airway–breathing first: SpO₂ 87% with rising work of breathing outranks everything else. Sequence: position upright → oxygen → rapid response → provider/imaging. Comfort measures and documentation follow; nothing about the chest pain or the calf changes the order.

  4. 4
    Generate solutions

    Raise the head of the bed to high-Fowler’s (upright positioning maximizes chest expansion and oxygenation — no order needed), apply oxygen targeting 92–96%, activate the rapid response, and stay with her. Anticipate the PE pathway: stat CTPA, ABG, ECG, troponin, and anticoagulation orders once confirmed. Keep her on the monitor and watch for the massive-PE heralds — hypotension, syncope, JVD.

  5. 5
    Take action

    Position and oxygenate immediately, call the rapid response, and deliver the SBAR: "Post-op day 2 right hip replacement, sudden dyspnea and pleuritic chest pain, SpO₂ 87% on room air now on O₂, HR 118, RR 28, lungs clear, right calf swollen and tender, SCDs had been off. I’m concerned for PE — requesting evaluation and anticipate stat CTPA and anticoagulation orders." Naming the suspected diagnosis with the pattern behind it is what gets the right test ordered fast.

  6. 6
    Evaluate

    Success looks like: SpO₂ climbing into the 92–96% target on the ordered oxygen, respiratory rate settling, hemodynamics holding, CTPA obtained, anticoagulation running with a therapeutic aPTT if heparin is chosen. Re-escalation triggers: SBP < 90, syncope, JVD, or worsening hypoxemia — the obstructive-shock heralds that would put thrombolytics on the table.

Scenario — you’re the nurse

Work each question before revealing the answer. Rationales explain the wrong options too.

Orthopedic unit · 1030, post-op day 2

A 71-year-old woman, post-op day 2 after right total hip replacement. Mostly in bed since surgery; up to the chair once yesterday. She puts on her call light: sudden shortness of breath and right-sided chest pain that started minutes ago. She tells you, "Something is really wrong with me."

1030 vitals — HR 118 · BP 132/84 · RR 28 · SpO₂ 87% on room air · T 37.1 °C
Assessment — anxious, speaking in short sentences; lungs clear bilaterally; sharp right chest pain worse with each deep breath
Legs — right calf swollen and tender compared to the left
Orders — sequential compression devices while in bed (found off at the bedside); no pharmacologic VTE prophylaxis on the MAR
Baseline — SpO₂ 95% on room air this morning; ambulating with walker yesterday without dyspnea
Q1 Select all that apply
Which findings require immediate follow-up? Select all that apply.
  1. A. SpO₂ 87% on room air with sudden shortness of breath
  2. B. Right calf swelling and tenderness
  3. C. Blood pressure 132/84 mmHg
  4. D. Sudden anxiety — "something is really wrong with me"
  5. E. Temperature 37.1 °C
  6. F. Sharp chest pain that worsens with each deep breath
Reveal answer & rationale
Answer: A, B, D, F
Sudden hypoxemia (A) is the emergency headline. The swollen calf (B) is the probable embolic source — the DVT that launched the clot. New unexplained anxiety and a sense of doom (D) sit on the classic PE sign list and must never be dismissed as nerves. Pleuritic pain (F) is pleural irritation from an infarcting lung segment. The BP (C) is currently adequate and the temperature (E) is normal — neither demands action, though the BP now needs watching, because hypotension is the herald of obstructive shock.
Q2 Multiple choice
Sudden dyspnea, SpO₂ 87%, HR 118, and pleuritic chest pain — with clear lung sounds — in a post-op patient most likely indicate:
  1. A. A panic attack triggered by post-operative pain
  2. B. Pulmonary embolism — a perfusion problem, which is why the lungs sound clear
  3. C. Hospital-acquired pneumonia
  4. D. Fluid overload with early pulmonary edema
Reveal answer & rationale
Answer: B
Unexplained hypoxemia with a normal chest exam is the PE hook (B): the alveoli are ventilated but not perfused, so there is nothing abnormal to hear. Anxiety (A) is the classic mislabel — but a panic attack does not produce an objective SpO₂ of 87%. Pneumonia (C) and pulmonary edema (D) are alveolar problems — they announce themselves with fever/focal findings or crackles, and her chest is clear with a normal temperature.
Q3 Put in order
Put the nurse’s first four actions in priority order:
  1. A. Activate the rapid response team
  2. B. Raise the head of the bed upright (high-Fowler’s)
  3. C. Apply oxygen per unit protocol
  4. D. Document the findings and notify the surgeon’s service
Reveal answer & rationale
Correct order: B → C → A → D
Position first — sitting the patient upright maximizes chest expansion and oxygenation instantly and needs no order. Oxygen next for the SpO₂ of 87%. Then the rapid response, which brings the team and the PE pathway to the bedside. Documentation and routine notification (D) come last — they never precede stabilizing an hypoxemic patient, and calling first (A first) would leave her sitting flat and hypoxic while you are on the phone.
Q4 Multiple choice
The provider orders a stat CTPA without a D-dimer. Why is skipping the D-dimer correct here?
  1. A. D-dimer results take too long to be useful in an emergency
  2. B. Her pretest probability is high — D-dimer can only rule out PE at low/intermediate probability, and recent surgery would falsely elevate it anyway
  3. C. A negative D-dimer would still require CTPA in every patient
  4. D. D-dimer cannot be interpreted in patients over 70
Reveal answer & rationale
Answer: B
With DVT signs, no better alternative diagnosis, tachycardia, and surgery within 4 weeks, her Wells picture is PE likely — and high pretest probability goes directly to imaging because a D-dimer can never rule PE in (B). It is an acute-phase reactant, falsely elevated by trauma, surgery, and inflammation. Turnaround (A) is not the principle. (C) is backwards — at low/intermediate probability a negative quantitative D-dimer excludes PE with no imaging at all. Age (D) doesn’t invalidate the test; it just raises the cutoff (age × 10 ng/mL after 50).
Q5 Select all that apply
CTPA confirms PE and a heparin infusion is started. Which findings must the nurse report immediately? Select all that apply.
  1. A. aPTT of 1.8 × the patient’s baseline
  2. B. Dark, smoky-colored urine
  3. C. A new severe headache
  4. D. Platelet count falling from 240 to 90 ×10³/µL
  5. E. Heart rate 88 and regular
Reveal answer & rationale
Answer: B, C, D
Smoky urine (B) is an internal-bleeding indicator — blood in the urinary tract. A new severe headache (C) on anticoagulation is intracranial hemorrhage until proven otherwise. A falling platelet count (D) flags heparin-induced thrombocytopenia, which forces a change of drug. The aPTT of 1.8 × baseline (A) sits inside the 1.5–2.2 × therapeutic target — that is the infusion working, an expected finding. A regular HR of 88 (E) is reassuring: the tachycardia of the acute event is resolving.

Common questions

What causes pulmonary embolism?
Common causes and risk factors include prolonged immobility — bed rest > 3 days; any travel > 4 hours, recent surgery — most commonly orthopedic (hip/knee replacement), also abdominal and brain, lower-limb fracture & major trauma, active cancer — highest risk: pancreatic, hematologic, lung, gastric, brain; highest when metastatic, prior dvt or pe — recurrence risk is high; unprovoked events recur at 2–3× the rate, and others.
Which findings should a nurse report immediately in pulmonary embolism?
Report immediately: Sudden-onset dyspnea, Hypoxemia with clear lung sounds and a normal chest film, Presyncope or syncope, JVD, parasternal lift, a third heart sound, cyanosis, falling BP, Obstructive shock → cardiac arrest. These signal deterioration that needs rapid intervention.
Which medications are used to treat pulmonary embolism?
Commonly prescribed drug classes include Anticoagulants — each is covered in depth in the pharmacology course.
Why are the lungs clear in a pulmonary embolism?
Because PE is a perfusion problem, not a ventilation problem. The clot blocks blood flow to a lung segment while air still reaches its alveoli — dead-space ventilation. The airways and alveoli are open and dry, so there are no crackles or wheezes to hear. That is why unexplained hypoxemia with a normal chest exam should raise suspicion for PE rather than lower it.
Does a negative D-dimer rule out a PE?
Only when pretest probability is low or intermediate — there, a quantitative D-dimer under 500 ng/mL (sensitivity ≥ 95%) safely excludes PE with no imaging. At high pretest probability the D-dimer is skipped and the patient goes straight to CTPA. A positive D-dimer never rules PE in: it is an acute-phase reactant, falsely elevated by pregnancy, cancer, surgery, infection, and age.
How long does anticoagulation continue after a PE?
All patients receive at least 3 months. Therapy extends beyond that when the PE was unprovoked (a 2- to 3-fold higher recurrence risk than a provoked PE) or when risk factors persist, weighed against bleeding risk. Anticoagulants don’t dissolve the clot; they hold the line while the body’s own fibrinolysis clears it and prevent the next one.

Sources

Reviewed by Hae Suk Lee, RN

Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.

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