Case 3.1

critical-care2

Prepared by Dr Julie Nguyen

Case presentation:
An 18-year-old African-American woman with no significant past medical history, presented to the ED complaining of cough, fever, generalized weakness, and worsening dyspnea for a week.  The patient was tachycardic, tachypneic and hypothermic.  Her labs showed leukocytosis, thrombocytosis, and coagulopathy. She had an anion gap of 21 and lactic acid of 6.7.  Her d-dimer was elevated and troponin level was 5.86. CT scan of her chest showed a massive bilateral PE in the main pulmonary arteries.  Lower extremity duplex did not show presence of DVTs.  The patient was admitted to the MICU where she was intubated secondary to persistent hypoxia (pulse ox 70-80%) despite receiving supplemental oxygen therapy.  TEE was done and showed a thrombus in the right ventricle.  Patient was treated with a bolus dose of TPA, as well as heparin drip.  She also was transfused with FFP in order to correct her coagulopathy and hypofibrinogenemia.

The patient deteriorated while in the MICU.  She was transferred to Children’s hospital the following day as a possible candidate for ECMO therapy.  A cardiac catheterization was performed, but was unsuccessful in removing the thrombus.  Local TPA infusion was done instead and the patient was continued on a heparin drip.  ECMO was not started because it was felt that the patient would not benefit from it at this time due to prolong hypoxia and multi-organ system failure.  Patient subsequently expired on hospital day #4.

Fibrinolytic therapy in Pulmonary Embolism
Thrombolytic agents activate plasminogen to form plasmin, resulting in accelerated lysis of thrombi. Common thrombolytic regimens include tPA, streptokinase, and urokinase. Streptokinase is antigenic and can cause immunologic sensitization and allergic reaction; tPA was associated with more rapid clot lysis and fever bleeding complications. Thrombolytic agents have been used in STEMI, stroke, phlegmasia cerula dolens  and central venous catheter clearance.

Indications:
•    Persistent hypotension (SBP<90mmHg or drop in SBP>40mmHg from baseline)
•    Severe hypoxemia
•    Substantial perfusion defect
•    Right ventricular dysfunction
•    Free floating right atrial or ventricular thrombus
•    Patent foramen ovale
Thrombolytic therapy accelerates clot lysis and is associated with short-term physiologic benefits, but has not been shown to improve mortality. Despite the lack of demonstrable mortality benefit, most clinicians accept massive PE as an indication for thrombolysis because successful therapy can be life saving. The risk versus benefits of thrombolysis should always be weighted on a case-by-case basis.

ECMO in the treatment of PE in adults
ECMO (extracorporeal membrane oxygenation) was first developed by Dr. Gibbon Jr. in 1953.  The idea is to remove deoxygenated blood from the body, oxygenate it, and return it back to the body.  This is similar to the idea of cardiopulmonary bypass but there are subtle differences.  The goal of ECMO is to allow the heart and lungs to rest from the high levels of oxygen and airway pressures that are required for ventilation and oxygenation.  It is a bridge to definitive therapy.

ECMO table
The use of ECMO has been mainly utilized in the pediatric population, especially in neonates.  Most of the studies and data on ECMO are within the pediatric population.  It has not been well studied in the adult population and the success rate varies.

Here are the indications and contraindications/exclusions for the use of ECMO in adults.

Indications:

  • Cardiac or lung diseases that are acute, life threatening, unresponsive to standard conventional therapy, and are thought to be reversible.
  • It has been mainly used for ARDS in adults
  • No clear indications for PE

Contraindications/Exclusions:

  • More than 10 days on mechanical ventilation
  • Age > 65 years old
  • Contraindications to anticoagulation
  • Necrotizing pneumonia
  • Multiple system organ failure
  • Terminal underlying disease
  • Major or irreversible CNS injury

Sherwin’s Critical Care is an education module that focuses on various aspects of critical care relevant to the practice of Emergency Medicine.   These are real cases as managed in the ED.  All postings are HIPAA compliant.

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