Pulmonary Embolism and Intracardiac Shunt

Today we had a great discussion of the management of a massive vs sub-massive pulmonary embolism.  We also discussed how management would change in the setting of large intra-atrial shunt. 

Management Considerations for Acute PE:

            -O2 support:

                               -If escalating to intubation use a low PEEP as high PEEP decreases preload and patients with RV dysfunction are in a pre-load dependent state.

                              -If intubating use caution as induction medications can blunt the catecholominergic state.

           -Hemodynamic Support:

                               -Give IVF, usually 500cc to 1L depending on situation, based on animal models using more fluids can be deleterious. 

                               -If fluids do not resuscitate the patient then quickly move to vasopressors, NE is usually vasopressor of choice.

           - Fibrinolysis vs Catheter directed fibrinolysis vs anticoagulation:

                               - Systemic Fibrinolysis is the preferred treatment for patients with massive PE if there are no contraindications to systemic fibrinolysis.

                               -Other possible treatments include catheter directed thrombolysis, surgical embolectomy, percutaneous embolectomy,

           -Long Term Anticoagulation:

                               -Based on the 8/2016 CHEST guidelines, use of a NOAC is preferred over vitamin K antagonist for the treatment of PE.

The effect of an intra-cardiac shunt on acute pulmonary embolism physiology.  The hypoxia seen in PE is thought to be due to right to left shunt and V/Q mismatch.  When a patient has an acute onset increase in right heart pressure in the setting of a pre-existing intra-cardiac shunt the percentage of CO that moves through the shunt significantly increases (depending on the extent of RV dysfunction), this can be protective from a hemodynamic standpoint as it preserves LV CO, however it can significantly worsen hypoxia as seen in our patient.