Do obese patients bleed more? A prospective study of blood loss at total hip replacement

This study compares blood loss at total hip replacement in obese and non-ob ese patients. We made a prospective study of intra-operative and postoperat ive blood loss in 80 consecutive primary cemented hip replacements. Patient s' obesity was classified according to body mass index (BMI). Overall mean total blood loss was 1050 ml. Obese patients (BMI > 30) bled s ignificantly more (P < 0.0001) than those of optimal weight (BMI < 26), whe reas those overweight (BMI 26-30) did not. The mean excess blood loss in ob ese patients wins 380 ml (95% confidence interval, 200-560 ml). At a time when the prevalence of obesity is increasing, this study quantifi es the risks of greater blood loss with respect to obesity and aids informe d consent,