Comparative evaluation of methods to measure blood loss after heart surgery under cardiopulmonary bypass

Abstract

Objective. To perform a comparative analysis of three methods for assessing blood loss (gravimetric, hemoglobin dilution, hemoglobin balance) in patients with heart surgery under cardiopulmonary bypass (CB).Materials and methods. The study involved 35 patients over the age of 18 who underwent heart surgery under CB. The volume of blood loss was assessed by the gravimetric method and compared with the blood loss volume calculated by hemoglobin dilution and hemoglobin balance methods.Results. After the patient was admitted from the operating room to the intensive care unit, the blood loss calculated by the hemoglobin dilution method did not differ from the blood loss measured by the gravimetric method. After 12-18 hrs after surgery, the blood loss calculated by hemoglobin dilution and hemoglobin balance methods did not differ from the blood loss measured gravimetrically. After 36-42 hrs after surgery, blood loss calculated by hemoglobin dilution and hemoglobin balance formulas was statistically significantly different from that measured by gravimetric method.Conclusion. The blood loss calculated by the hemoglobin dilution method corresponds to the blood loss measured by gravimetric method at the stages “admission from the operating room” and “12-18 hours after surgery”. The volume of blood calculated by the method of hemoglobin balance at the stage “12-18 hours after surgery” corresponds to the volume of blood measured by gravimetric method. All of the above calculation methods at the stage of the study “36-42 hours after surgery” cannot be recommended for calculating the volume of blood loss after heart surgery with cardiopulmonary bypass.