<unk>  refers to the partial pressure of<unk> es in blood. There are several significant purposes for measuring<unk><unk> . The most common<unk><unk> s measured are oxygen<unk>  (PxO2), carbon dioxide<unk>  (PxCO2) and carbon monoxide<unk>  (PxCO). The subscript x in each symbol represents the source of the<unk>  being measured: "a" meaning arterial, "A" being alveolar, "v" being venous, and "c" being capillary. Blood<unk>  tests (such as arterial blood<unk>  tests) measure these partial pressures.
Blood gas tension
Oxygen saturation 
Oxygen saturation
Breathing gas
Respiratory rate
Blood pressure
Bottled gas
Heart rate