Blood loss and transfusion rates following total hip arthroplasty: a multivariate analysis.

This study aimed to identify factors that inde- pendently predict increased rates of transfusion following total hip arthroplasty (THA) surgery. A retrospective analysis of all patients undergoing THA surgery over 12 months was performed. Electronic operative records were analysed to determine the following patient factors: American Society of Anesthesiologists (ASA) grade, body mass index (BMI), co-morbidities, indication for surgery, surgical technique, type of implant used, haematological markers, hospital length of stay (LOS) and complications. A total of 244 patients were included. There were 141 females (58%) and 103 males (42%). The median age was 65±12. The median pre-operative blood volume was 4500mls (IQR; 4000-5200). The median blood loss was 1069mls (IQR; 775-1390). The total number of patients requiring transfusion was 28 (11%), with a median of two units being transfused. Pre-operative haemoglobin (p<0.001) level, haematocrit (p<0.001) level and weight (p=0.016) were found to be predictive of transfusion requirement as well as ASA grade (p=0.005). Application of an intra-operative surgical drain was associated with higher rates of transfusion (p<0.001). Our study strengthens the evidence that pre-operative haemoglobin and haematocrit levels are valuable predictors of patients requiring transfusion. Additionally, ASA grade may be viewed as a helpful factor in predicting risk of transfusion. A strategy incorporating pre-operative optimisation of modifiable factors may reduce rates of transfusion requirement.