Table 4 Comparison between the three sampling sites expressed by bias (2SD) for the difference between arterial and calculated arterial blood values from venous blood

	N	pH	p Value	Pco₂ (kPa)	p Value
Peripheral blood	103	0.002 (0.027)		−0.040 (0.517)
Central venous blood	73	0.011 (0.023)	<0.05 (S)	−0.176 (0.354)	<0.05 (S)
Mixed venous blood	18	−0.005 (0.021)		0.055 (0.403)

S, significant.
The sampling sites were compared using one-sided ANOVA.