measurement of acidity/alkalinity: normal range 7.37-7.45
pH > 7.45 = alkalosis
pH< 7.35 = acidosis
correlates well with arterial pH 
measures the partial pressure of oxygen dissolved in the serum; that is, the dissolved oxygen not carried by hemoglobin
significantly lower than and nonindicative of arterial oxygen pressure (PaO2)
The amount of carbon dioxide dissolved in arterial blood. The normal range is 35 to 45 mm Hg.
PvCO2 >45 = primary respiratory acidosis
PvCO2 <35 = primary respiratory alkalosis
correlates with controversial accuracy with PaCO2: see discussion below
calculated from PvCO2 and pH with Henderson-Hasselbalch equation
correlates well with serum HCO3 
an estimation of the metabolic component of acid/base status: how much "extra base" there is in the system
the theoretical number of H+ needed to bring pH to 7.40 at pCO2=40
reference range -2 to +2
positive in metabolic alkalosis, negative in metabolic acidosis
can be expressed as "base deficit", with the same but opposite values
e.g. base excess=-8 in a case of lactic acidosis; base deficit=+8
positive in metabolic alkalosis, negative in metabolic acidosis
e.g. base excess=-8 in a case of lactic acidosis; base deficit=+8
Venous blood gas
Arterial blood gas analysis
ECG 
Age adjusted D-dimer
Cardiac ultrasound
Cardiac enzymes
D-dimer
Pulmonary artery catheter