Investigation and Management of Pulmonary Embolism

This is an abbreviated version of the full GGC guideline Investigation and Management of Pulmonary Embolism. This guideline is for use in non-pregnant adults in acute care. For suspected pulmonary embolism (PE) in pregnant patients, refer to the full GGC guideline, Thromboembolic Disease during Pregnancy and the Puerperium. 

Introduction

• PE occurs when emboli, arising from a blood clot in the venous system, obstruct the pulmonary arterial system, leading to respiratory and cardiac dysfunction.
• All patients with PE should have a follow up in a PE clinic where anticoagulation duration is decided.

This guideline includes information on:

• Investigation of suspected PE (including guidance on how to stratify severity of PE)
• Management of high-risk (massive) PE
• Management of intermediate-risk PE
• Management of low-risk PE.

Investigation of Suspected PE

Signs and symptoms which may accompany PE include:

• Chest pain (often pleuritic), cyanosis, dyspnoea, haemoptysis, syncope.
• Tachycardia, hypotension, raised JVP, hypoxaemia, tachypnoea.

Guidance on how to stratify risk of PE and determine severity of PE:

• Suspected PE should be systematically stratified and managed according to the risk of haemodynamic compromise - see figure 1 (page 3 of the GGC guideline) for general overview of investigation and management.
• If haemodynamic compromise (systolic BP <90mmHg), then treat urgently as per high-risk (massive) PE.
• If haemodynamically stable, use pre-diagnostic predictive scores to assess the need for further investigations and treatment - see figure 2 and scoring tools below (PERC, Geneva).
• Patients with confirmed PE should have a severity assessment to determine the location of initial management i.e. inpatient or outpatient - see figure 3 - Severity Assessment (page 6 of full GGC guideline) and sPESI score which will indicate whether PE is considered high risk, intermediate-high risk, intermediate-low risk or low risk.

High-risk (massive) PE

This is defined as acute PE with sustained hypotension (systolic BP <90mmHg, for a period >15 minutes) or requiring inotropic support (not otherwise explained by another cause e.g. hypovolaemia, sepsis, arrhythmia or left ventricular dysfunction).

Investigations:

• Confirmation by CTPA is preferable and also allows assessment of pulmonary vascular anatomy and right ventricle (RV) assessment.
• If CTPA is not possible due to clinical condition (e.g. intubated), urgent bedside transthoracic echocardiogram (TTE) should be performed to assess for RV size and dysfunction.

Initial management of high-risk PE:

• Seek immediate senior advice as patient may need transfer to CCU / ICU / HDU / ED resus.
• Give resuscitative care - oxygen, invasive blood pressure monitoring, IV fluids and inotropic support.
• Perform urgent CTPA or TTE (if CTPA not possible / not available).
• Heparinise with unfractionated heparin IV (UFH) bolus (5,000units) then IV infusion (18units/kg/hour adjusted to maintain APTT ratio of 1.8–2.8) – further dosing and monitoring details, including if patient is <50kg or >100kg, can be found in the Drug therapy / treatment options section. If UFH is not available, low molecular weight heparin (LMWH) is acceptable as well in the management of the patient.
• If there is persistent hypotension (systolic BP <90mmHg) and either CTPA confirms PE, TTE demonstrates RV dilatation / dysfunction or patient is in peri-arrest, then consider thrombolysis as follows:
  • Alteplase IV 10mg over 1-2 minutes followed by 90mg over 2 hours (max 1.5mg/kg if <65kg). If this is not available, seek senior advice as may need to consider other thrombolytic agents which are not licensed for PE.
  • Continue heparin, maintain APTT ratio 1.8–2.8
  • If there are concerns of a high bleeding risk, consider low dose thrombolysis - alteplase IV 10mg over 1-2 minutes followed by 40mg over 1 hour.
  • If thrombolysis is contraindicated, consider catheter-directed thrombolysis or surgical embolectomy - further information in the full GGC guideline.
  • Be aware that when considering thrombolysis the risk of major haemorrhage is significantly increased in the older patient.
  • A summary of reperfusion therapy and further guidance on the administration of systemic thrombolysis and contraindications can be found in the full GGC guideline.

Unfractionated heparin can be stopped once the patient is deemed to be haemodynamically stable. Ongoing anticoagulation should then be commenced. The choice of ongoing anticoagulation is discussed in the Drug therapy / treatment options section.

Intermediate-risk PE

Patients with intermediate-risk PE may present with significant symptoms and/or large volume clot on CTPA whilst not meeting the high-risk criteria. These patients may have a positive troponin, a high risk sPESI or evidence of RV dysfunction on imaging. Intermediate-risk patients can deteriorate rapidly, warranting consideration for level 2 monitoring and admission for observation.

Management of intermediate-high risk PE:

• If hypotensive (systolic BP <90mmHg) refer to the high-risk (massive) PE section above.
• If patient appears critically unwell (e.g. marked hypoxaemia, high lactate, signs of right heart failure) but does not meet the criteria for high-risk PE, reperfusion therapy should still be considered. See the full GGC guideline for guidance on reperfusion therapy.
• Monitor in a level 2 bed or an acute care environment with cardiac monitoring and adequate nursing provision.
• Monitor as an inpatient for a minimum of 48 hours.
• Treat with LMWH for a longer period (i.e. 2-3 days) before converting to a direct oral anticoagulant (DOAC). See Drug therapy / treatment options section.
• If clinically deteriorating (e.g. progressive hypoxaemia, rising heart rate, high or rising lactate, clinical features of circulatory compromise e.g. cold, clammy, cyanosis), consider reperfusion therapy in any modality. See the full GGC guideline for guidance on reperfusion therapy.

Management of intermediate-low risk PE:

• Monitor the patient on a ward for a minimum of 24 hours, and discharge within 48 hours should be guided by senior clinical judgement.
• Once PE is confirmed on CTPA, LMWH can be stopped and a DOAC commenced for acute and ongoing treatment. See Drug therapy / treatment options section.

Management of low-risk PE

• Assess the patient for early discharge / ambulatory care. See figure 4 and the assessment criteria to determine suitability for outpatient management.
• If patient is haemodynamically unstable, consider massive PE and refer to the brief guidance above and the full GGC guideline.

Ambulatory management of PE

• Give treatment dose LMWH or DOAC (See Drug therapy / treatment options section).
• Ensure the patient has been educated on their new anticoagulant and how to self-administer.
• The GGC DOAC booklet can be given to patients and can be found here: “GGC Medicines: Direct Oral Anticoagulation (DOAC) Patient Information Booklet and Alert Card”
• Request CTPA
• Ensure the patient has enough doses of LMWH/ DOAC to administer at home until the CTPA.
• Explain plan to the patient – ensure they understand follow-up, CTPA and LMWH / DOAC.
• Request follow-up as per local protocol e.g. hot clinic, ambulatory care pathway.

Follow-up arrangement on discharge from hospital

The duration of anticoagulation therapy will be determined during the follow-up clinic review. Before discharging the patient: 

• Ensure a follow-up clinic appointment is arranged
• Advise the patient to continue taking their anticoagulant medication until they are reviewed at their follow-up appointment.

Predictive Pre-diagnostic Scores

Revised Geneva Predictive Risk Score - assesses the probability of PE in order to inform investigations. See page 4 of the full GGC guideline for details. 

Pulmonary Embolism Rule Out Score (PERC Score) - this is used for patients with a low likelihood of PE, who demonstrate low-risk features and can be used to rule out PE in the Assessment Unit or the Emergency Department.

Simplified Pulmonary Embolism Severity Score (sPESI Score)

Guideline reviewed: March 2026

Page updated: April 2026