The correlation between the citrate contained in the transfused blood products and the plasma concentration of ionised calcium in cardiac surgery patients
Abstract
Objective: The goal of the study was to evaluate the correlation between the dose of infused citrate and plasma ionized calcium changes in cardiac surgery patients requiring transfusion treatment. The secondary goal was to establish the incidence of perioperative hypocalcaemia.
Design: Prospective, observational, non-interventional study. Setting: Department of Anaesthesia and Intensive Care Medicine, University Hospital Hradec Kralove, Charles University, Faculty of Medicine, Hradec Kralove.
Patients and methods: During the study period, 42 cardiac surgery patients treated with transfusion were enrolled into the study. All the patients underwent cardiac surgery procedures using cardiopulmonary bypass.
Blood samples for blood gases, acid base balance and biochemistry were taken before transfusion, just after finishing and at the time of ICU admission, and on the first postoperative day. Correlation analysis was used to detect correlation between the infused citrate load and the plasma ionized calcium change.
Statistical analysis was performed to evaluate the statistical significance of ionized calcium and pH alterations between measurements. Result: No correlation between the infused citrate load and the plasma ionized calcium change was found, with correlation coefficient r = -0.21, alpha = 0.01.
There was statistically significant decrease in the value of the plasma ionized calcium before and just after finishing the transfusion treatment (p < 0.05). No ionized hypocalcaemia was detected throughout the study.
Conclusion: We found no correlation between the citrate load in the transfusion units and the plasma ionized calcium, using routine perioperative measurement of ionized calcium. Routine measurement of ionized calcium during transfusion treatment may eliminate the empirical bolus administration of calcium, which can be risky in many cardiac surgery patients.