A 56 year old female with septic shock and multiple organ failure is admitted to intensive care. She is endotracheally intubated and ventilated. A central venous catheter is inserted into her right subclavian vein, a Vas Cath is inserted into her right femoral vein and a pulmonary artery catheter is inserted via her left subclavian vein.
a) Blood gas samples are simultaneously taken from all three catheters. The oxygen saturations are as follows:
State which site each of the blood gas samples is taken from and justify your answer: