A PROSPECTIVE RANDOMISED STUDY OF POST OPERATIVE BLOOD SALVAGE WITH AUTOLOGOUS RETRANSFUSION FOLLOWING PRIMARY TOTAL HIP REPLACEMENT

Abstract

Introduction: The rate of homologous blood transfusion following primary total hip replacement (THR) can be as high as 30–40% and is not without risk. Postoperative blood salvage (POS) with autologous blood transfusion may minimize the necessity for HBT but the clinical, haematological and economic benefits have yet to be clearly demonstrated for primary THR.

The aim of this prospective randomized study was to determine if the use of POS affects postoperative haemoglobin and haematocrit values and reduces the rate of homologous blood transfusion. Secondary outcomes measures included length of hospital stay and patient satisfaction. A cost analysis was conducted on the basis of the results.

Methods: Calculations following a preliminary study revealed that 72 patients would be required in each group to detect a significant difference of 0.7 gdL⁻¹ in the post operative haemoglobin level (with power of 80% and an α value of 0.05). The patients were block randomized on reduction of the primary THR, prior to closure, to receive either two vacuum drains or the autologous retransfusion system.

Results: There were 82 patients in the vacuum drain group and 76 patients in the autologous retransfusion group. Haemoglobin and haematocrit values were not significantly different between the groups but significantly fewer patients with the autologous system had a postoperative haemoglobin value < 9.0 gdL⁻¹ (8% vs. 20%, p = 0.035). Significantly fewer patients with the autologous system required HBT (8% vs. 21%, p = 0.022). There was an overall cost saving in this group.

Discussion: This study confirms that POS results in significantly fewer patients with a post-operative Hb below 9.0 gdL⁻¹ and confirms that POS significantly reduces the necessity for homologous blood transfusion following primary THR. As a result, our unit uses the autologous retransfusion system for primary THR.