Comparisons of Gas Analysis in Arterial, Venous and Warmed Venous Blood During Inhalation General Anesthesia

Abstract

Background：We determine whether venous blood, when sampled under carefully controlled conditions, was an acceptable alternative to arterial blood for the measurement of arterial blood gas analysis during inhalation general anesthesia. Materials and Methods：The arterial blood values of the carbon dioxide tension (PCO2), pH, base excess (BE), oxygen tension (PO2) and oxygen saturation (SO2) were compared with the values of venous blood drawn from the cephalic vein as non controlled routine method and as localized warmed method during inhalation general anesthesia with sevoflurane and N2O (50%) in 20 cases. Results：The blood gas analysis values of non controlled cephalic venous blood were close to those of arterial blood. They was similar between the PCO2 (42.5 ± 0.97 vs. 38.7 ± 0.92 mmHg), pH (7.35 ± 0.01 vs. 7.39 ± 0.01) and BE (-3.13 ± 0.62 vs. -0.18 ± 0.13 mEq/l) of non controlled cephalic venous and of arterial blood. Although the PO2 in non controlled cephalic venous blood was significantly less than that in arterial blood(130.8 ± 8.1 vs. 245.3 ± 6.8 mmHg), the difference in SO2 was small(98.9 ± 2.1 vs. 99.7 ± 0.4%). The blood gas values of warmed cephalic venous blood were more similar to those of arterial blood (PCO2, 41.2 ± 0.91 vs. 38.7 ± 0.92 mmHg; pH, 7.37 ± 0.01 vs. 7.39 ± 0.01; BE, -2.30 ± 0.62 vs. -0.18 ± 0.13 mEq/l; PO2, 157.3 ± 11.4 vs. 245.3 ± 6.8 mmHg; SO2, 99.2 ± 1.3 vs. 99.7 ± 0.4%) than to those of non controlled cephalic venous blood. Conclusion：We found that warmed cephalic venous blood during inhalation general anesthesia can be arterialized and PCO2, pH, BE and SO2 of warmed cephalic venous blood were not significantly different to those of arterial blood. Therefore we conclude that it is reliable to use localized warmed cephalic venous blood for the measurement of arterial blood gas analysis during inhalation general anesthesia.