The analysis of the effectiveness of various methods for assessing the volume of blood loss during open heart surgery

Abstract

Objectives. To make a comparative analysis of six methods for assessing the volume of blood loss (gravimetric, Ward, Bourk, Gross, OSTHEO, Lopez-Picado methods) in patients undergoing open heart surgery under cardiopulmonary bypass (CPB). Material and methods. We examined 35 patients over the age of 18 who underwent heart surgery under CPB. The volume of blood loss was assessed by the gravimetric method and compared with the volume of blood loss calculated using formulas based on the patient’s hematocrit (Ward, Bourk, Gross, OSTHEO, Lopez-Picado methods). Results. After admission of the patients from the operating room, the blood loss volume calculated by the formulas differed statistically significantly from the blood loss volume measured by the gravimetric method. In 12-18 hours after the operation, blood loss calculated using the Lopez-Picado formula did not statistically differ from that measured by the gravimetric method, but 1.43 times exceeded the latter (p=0.019, Mann-Whitney test). In 36-42 hours after the operation, the calculated blood loss volume differed significantly in comparison with the measured by the gravimetric method. Conclusions. The blood loss volume calculated by the Lopez-Picado method corresponds to the volume of blood loss measured by the gravimetric method only at the stage “in 12-18 hours after the operation”. All of the above calculation methods at the remaining stages of the study significantly differ from the data obtained by the gravimetric method, and cannot be recommended for calculating the volume of blood loss after heart surgery with CPB.

Keywords

• cardiopulmonary bypass
• blood loss
• gravimetric method
• ward method
• bourk method
• gross method
• ostheo method
• lopez-picado method