Yes, you can take blood from the heart-lung machine. To make sure that the priming fluid and blood is fully mixed, we recommend waiting 10 minutes after the patient has been connected to the heart-lung machine before drawing the blood. We also recommend to add 100 mg Tranexmic acid to the prep-unit before drawing the blood to prevent fibrinolysis. N.B.: Heavy blood flow from the heart lung machine might casue bubbles in the preparation unit.