Q: 33 year old morbidly obese female presented to ER with shortness of breath. CT scan confirmed pulmonary embolism (PE). Echo confirmed severe right heart strain with clinical hemodynamic instability. Patient has been started on 2 hours regimen of thrombolytic (tPA 100 mg) intravenously, and transferred to ICU. What would be your approach to initiate heparin therapy?


Answer: 3 "rules of thumb" to follow while initiating Heparin post thrombolytic therapy in PE are 

1. Loading dose should be avoided

2. aPTT should be measured at the end of the infusion of the thrombolytic therapy. 

3. Heparin should be started with weight based calculation of 18 units/kg/hour only when the aPTT is less than twice its upper limit of normal.