Background: While the arteriopuncture is a painful and relatively risky procedure and may be complicated by some problems, venopuncture required for assessing the venous blood gases (VBG) is an easier procedure with fewer complications. Considering the mentioned notion, substituting the VBG values for of ABG values can prevent such complications. This study was carried out with the aim of determining whether the VBG values can be replaced for ABG values in the management of mechanically ventilated patients admitted in ICU wards.

Materials and Methods: This study was carried out on 102 patients admitted in ICU ward of Shahid Beheshti. After performing the Allen test, ABG was taken from radial artery of one hand and immediately VBG from the brachiocephalic vein of the other. The ABG and VBG indexes were calculated using a GEM3000 system. After the data collection and calculation of mean and standard deviation of all indexes, two methods were compared using paired t-test, subsequent correlation ratio and the linear regression model.

Results: Among the 102 hospitalized patients 70 were males and the remaining 32 females. The results of comparing the ABG and VBG indexes in terms of Pearson-correlation coefficient and the relevant significant level were: pH (0.801, P<0.001) PCO2 (0.835, P<0.001) HCO3 (0.768, P=0.369) PO2 (0.287, P<0.001) SaO2 (0.317, P<0.001) BE (0.810, P<0.011).

Conclusion: While there was a significant correlation between the ABG and VBG indexes, but with the consideration of the power of correlation, the substitution of VBG for ABG is not recommended for mechanically ventilated patients.