Table 1. Blood sampling protocol.

Sample	Description	Volume
1	Venous blood:	25 mL
	Taken from a central line immediately following insertion (i.e. after induction of anesthesia)
2	Venous blood:	25 mL
	Taken from a central line just before unfractionated intravenous heparin administered (i.e. just prior to the initiation of CPB)
3	Venous blood:	25 mL
	Taken from a central line:
	after grafts have been completed, normal ventilation resumed, taken off CPB and protamine given, but before chest closure
4	Venous blood:	25 mL
	Taken from a right pulmonary vein (i.e. sampling blood that has been through the ventilated lung) at same time as sample 3
5	Venous blood:	25 mL
	Taken from a left pulmonary vein (i.e. sampling blood that has been through the deflated lung) at same time as sample 3