RESUMO
During anesthesia and surgery, body homeostasis and tissue oxygen demand/supply balance is disrupted and blood lactate concentration in increased. We have studied the changes of blood lactate concentrations and arterial, venous oxygen contents during open heart surgery in 15 patients. Samplings were done at 1) before anesthetic induction, 2) after induction, 3) after sternotomy, 4) onset of cardiopulmonary bypass, 5) duing hypothermic cardiopulmonary bypass, 6) after cardiopulmonary bypass and 7) after operation. Blood lactate concentrations were inereased signifieantly at the onset of, during and after cardiopulmonary bypass and after operation(p<0.001). Arterial oxygen contents were decreased significantly at the onset of, during and after cardiopulmonary bypass(p<0.05). Venous oxygen contents were decreased significantly at the during and after cardiopulmonary bypass and after operation(p<0.05). There were significant negative correlations between arterial, venous oxygen contents and blood lactate concentrations. Changes of venous oxygen saturation, mean arterial pressure and pH had not significant relationships with the lactate concentrations.