Abstract

Objective: To determine whether venous blood gas values can replace arterial gas values during
cardiac surgery. We investigated the correlation of pH, Po2, Base Excess and HCO3 in arterial
and venous blood gases.
Methods: This prospective study was performed on 150 patients undergoing cardiac surgery in
Shahid Madani Heart Hospital in Tabriz, Iran in 2004. We measured of the arterial and venous
blood gases perioperative phase of cardiac surgery.
Results: There was not any significant difference between HCO3 in arterial and venous samples,
during and after surgery and intensive care unit (ICU) with FIO2=70% (P=0.767, 0.593, 0.399)
respectively. The correlation was just acceptable in pH at the beginning of surgery (r=0.858).
Conclusions: There were considerable correlations between pH and HCO3 but not in PCO2, and PO2.
We do not recommend venous blood gas for determining PO2, PCO2. (Rawal Med J 2008;33:29-
32).

Key words: ABG, venous blood, CABG, pH, Acid base.