Correlates of blood volume, red cell mass and plasma volume in coronary bypass patients

Abstract

Prebypass blood volume (BV), red cell volume (RBC) and plasma volume (PV) may affect haematocrit during and after cardiopulmonary bypass (CPB), volume shift in and out of the oxygenator during CPB and the need for blood transfusion. We have calculated BV, RBC, and PV in 1076 patients having coronary artery bypass (CABG). Multiple regression analysis was performed to determine the preoperative factors which correlated with BV, RBC and PV. BV was found to correlate significantly with body surface area (BSA), sex, ejection fraction and emergency operation. RBC correlated significantly with sex, smoking, weight, emergency operation and obesity (body mass index). Significant correlations were found between PV and BSA, ejection fraction, emergency operation and sex. Body size (BSA and weight) is a major determinant of BV, RBC and PV in coronary artery surgery patients. Female patients have significantly diminished BV, RBC and PV, the decrease is greatest for RBC. Equal increases in BV and PV are associated with decreased ejection fraction. Emergency operation is correlated with increases in BV, RBC and PV. RBC is increased in smokers and the obese (BMI).