SERUM IONIZED CALCIUM CHANGES FOLLOWING CITRATED BLOOD TRANSFUSION IN ANAESTHETIZED MAN

Abstract

We measured the serum ionized calcium concentration in six patients who received ACD blood infusions during general anaesthesia and found the average decrease to be 0.5 mg/100 ml after 500 ml of blood and 0.6 mg/100 ml after 1000 ml of blood. However, the ion concentration increased a mean of 0.3 mg/100 ml 10 minutes following complete infusion of the blood. We also studied the effect of Pa_{CO2 on ionized calcium level in six patients under general anaesthesia who did not receive blood intra-operatively and found that the ion concentration varied directly with the PaCO2 An equation for a regression line relating PaCO2 and calcium ion concentration was derived.}