Fig. 3

Relative importance of each covariate in predicting intraoperative blood loss by the variable importance method. Permutation variable importance was defined as a decrease in the model accuracy caused by permutation of an independent variable. All variables had statistically significant importance. eGFR, estimated glomerular filtration rate; BMI, body mass index; Cre, creatinine; PS-ASA, performance status classification by American Society of Anesthesiologist; ALT, alanine aminotransferase; CRP, C-reactive protein; ALP, alkaline phosphatase; BUN, blood urea nitrogen; APTT, activated partial thromboplastin time; AKI, acute kidney injury; ADL, activities of daily living; WBC, white blood cell; CKD, chronic kidney disease; AST, aspartate aminotransferase; CHF, congestive heart failure; Na, serum sodium; COPD, chronic obstructive pulmonary disease; PCI, percutaneous coronary intervention