ED Mx of pulmonary embolism (PE)

see also:

• epidemiology, pathology and clinical features of PE
• Ix of suspected pulmonary embolism (PE)
• Western Health Massive PE and Thrombolysis protocol - intranet only

• see investigation of suspected PE

• PE causes ~3% of out of hospital cardiac arrests (OHCA)
  • 4% of those with nonshockable rhythm
  • 22% of those with with nonshockable rhythm and history of thromboembolism (44% in those aged under 50yrs with these factors)
• thrombolysis PRIOR to arrest appears to halve mortality rates from ~50% in those who have severe haemodynamic compromise (hypotension with RV dysfunction) and from ~6% to 3% in those who just have RV dysfunction and raised troponin, but does increase intracranial bleed rates to around 2% and major extracranial bleeding to 6%¹⁾²⁾
• CPR and ACLS resuscitation has limited utility as the obstructed pulmonary circuit prevents blood flow to the systemic and cerebral circulation resulting in rapidly progressive severe hypotension and EMD/PEA cardiac arrest.
  • HOWEVER, CPR alone may achieve ROSC perhaps by dislodging clot (>40% if no thrombolysis and more than this if thrombolysed) with survival rates of perhaps 8-35% at 30days which appears to be similar whether thrombolysed or not during CPR although some studies seem to show a higher discharge home rate in thrombolysed patients³⁾
  • in general, once a fibrinolytic drug is administered, continue CPR, preferably a mechanical chest compression device, for at least 60 to 90 min (or at ROSC) prior to terminating resuscitation attempts
  • timely cardiopulmonary bypass with ECMO or emergency thoracotomy with pulmonary embolectomy are the only likely life-saving options that may increase survival above this
• avoid intubation if possible as this is likely to result in exacerbation of haemodynamic compromise and cause cardiac arrest

• patients who collapse with massive PE tend to die within 2hrs of onset unless aggressive Mx is instituted
• high flow oxygen
• move to a resuscitation cubicle
• IV access, take bloods for FBE, U&E, clotting, ABG's
• cardiac monitor
• rapid confirmation if possible via either bedside echo or CTPA
• early anticoagulation to reduce further clot forming (but this does not reduce existing clot!) such as:
  • unfractionated heparin 80 units/kg loading dose IV, followed by 18 units/kg/hr IV infusion, adjusted according to APTT.
    • preferred in high risk PEs where thrombolysis may be needed as it can be ceased in the event of major bleeding
• early thrombolysis for any patient who does not have overwhelming C/I and who has evidence of massive PE with:
  • hypotension (unlikely to be caused by sepsis, bleeding or dissection), and,
  • right heart failure (or very likely to have massive PE based on clinical history and findings)
  • or, controversially, consider in sub-massive PE esp. in those under 65yrs where bleeding risk is much lower, if either:
    • an episode of hypotension - such an episode in these patients suggests reserves are critical and death may be imminent!
    • evidence of right heart strain
    • massive ileo-femoral thrombosis
• thrombolysis dose if appropriate, preferably after discussion with respiratory:
  • see thrombolysis in Mx of PE
• cautious iv fluid loading, although this may worsen the outcome
• admit to a hospital preferably with access to ICU and ECMO if this would be considered in the patient - ie. not a palliative care patient.
• APTT should be checked after 4 to 6 hours and the dose of heparin adjusted if APTT is not in the therapeutic range. When the APTT is in the therapeutic range, the dose should be reviewed daily.
• warfarin should be started within 48 hours using the regimen for deep venous thrombosis (DVT)

• iv access, bloods for prothrombotic screen, U&E, FBE, baseline clotting
• if significant hypoxia or any episode of hypotension, see above under Mx of unstable patient.
• 12 lead ECG
• CXR if not already performed
• consider:
  • troponin - elevated troponin levels in pts with PE suggests RV strain and should probably be considered as “unstable”
  • echocardiogram to assess degree of RV strain - significant RV strain should also be considered “unstable”
  • evidence of RV dysfunction is an indication for hospital admission
  • evidence of RV dysfunction with raised troponin indicating injury is usually an indication for ICU admission &/or thrombolysis
• these patients are usually admitted (often under the respiratory unit rather than general medicine) for observation and commencement of anticoagulation
  • early anticoagulation with either heparin or enoxaparin reduces overall mortality from 30% to below 10%.
  • initial enoxaparin (preferred over heparin as lower bleeding rates and HIT for low risk PEs where thrombolysis is unlikely to be needed), then DOACs
• general indications for inpatient Mx (usually under the resp. unit):
  • age ≥ 70;
  • any one of: active cancer/ heart failure/ chronic lung disease/ cerebrovascular disease;
  • renal or hepatic disease
  • thrombocytopenia
  • pregnancy
  • high risk of bleeding - consider using the HAS_BLED or the Outpatient Bleeding Risk Index
  • large or massive PE:
    • any one of: pulse ≥ 110; SBP < 100 mmHg; altered mental status; SaO2 < 90%;
    • raised troponin indicating RV myocardial damage
    • echocardiographic or CTPA evidence of RV dysfunction
  • compliance issues (missing one dose of DOAC can be problematic)
  • high HOPPE-SAO2 score:
    • appears to identify ~25% of patients who would be suitable for outpatient Mx with a 30 day mortality < 2%
    • see HOPPE score for outpatient Mx of PE
  • high PESI score > 85:
    • see PESI score for severity of PE
• outpatient Mx if no indications for inpatient Mx:
  • may be suitable with DOACs / NOACs ⁴⁾ :
  • ensure the patient agrees with the plan and discuss with the patient the need to return to the ED for worsening shortness of breath (at rest or with exertion), syncope, worsening chest pain, or any other concern.
  • DOAC options:
    • rivaroxaban - 15mg bd for 21 days then 20mg once daily - write a script for BOTH to ensure patient does not cease after initial bd dose runs out
    • edoxaban - 60mg once daily but needs initial parenteral anticoagulation 5-10 days
    • apixaban - but needs long term bd dosing with compliance issues - 10mg bd for 7 days then 5mg bd
    • dabigatran - needs long term bd dosing with compliance issues - 150mg bd, and needs initial parenteral anticoagulation 5-10 days

• INR Rx range on warfarin Rx should be 2.0-3.0

• patients with irreversible and clinically apparent hyper-coagulable states, such as neoplastic disease, or, chronic thromboembolic pulmonary hypertension⁵⁾, then life long Rx.
• patients with a non-transient risk factor, then 12 months Rx.
• patients with a transient risk factor, then 6 months Rx.

• patients who develop new PE's whilst on adequate anticoagulation should be considered for IVC filter insertion to prevent further emboli
• such patients tend to have a higher risk of underlying risk factors such as occult neoplasms and this should be considered in their work up.