Blood when allowed to flow out from body to the circuit tubings can get clotted. To prevent this, heparinisation is done. Patient is administered 3 mg/kg body. weight of heparin added before conilected to CPB. The activated clothing time is brought to more than 400 sec, then connected to CPB. 1 mg/kg body weight of heparin is added into the circuit every hour. ACT is monitored hourly.
Surgeon inserts cannulas into the right atrium via the superior and inferior vena cava (venous cannulation) and into the ascending aorta (arterial cannulation). Aorta is cross-clamped.