Yoeri Bemelmans

Tranexamic acid in hip and knee arthroplasty 35 3 The dosage, orally and intravenously, depended on the weight of the patient; <100kg: 1000mg, >100kg: 1500mg. In case of a known hypersensitivity for TXA, severe renal function disorders (<50 mL/min creatinine clearance or dialysis depending) or recent history (<6 months) of a vascular event (e.g. cerebrovascular/myocardial infarction or deep venous thrombosis/pulmonary embolism), TXAwas not given. Postoperatively, all patients received thrombosis prophylaxis with the use of lowmolecular weight heparin (LMWH), except for patients whowere on vitamin K antagonists (VKA) or non-VKA oral anticoagulants (NOAC) prior to surgery. LMWH thrombosis prophylaxis (subcutaneous injection of 5000IE (Dalteparin ® , Pfizer, New York City, United States) once daily started on the day of surgery and was continued up to six weeks after the arthroplasty. After surgery patients were monitored at the Post Anaesthesia Cure Unit (PACU) for several hours, before being transferred to the orthopaedic ward. Postoperatively, haemoglobin (Hb) levels were determined the first postoperative day. Except for patients undergoing UKA surgery via the outpatient pathway, Hb levels were not routinelymeasured. In case of general unwell-being, Hb levels were determined. Depending onHb levels and clinical evaluation of the patient by the orthopaedic ward physician, allogenic blood transfusion was considered according to the recent national guidelines [20]. Data collection Data collection was performed via the in-hospital registration system of blood transfusions and the patient’s digital medical records. Outcome measures Theprimaryendpoint of this studywas the incidenceof blood transfusions inelectivehip- and knee arthroplasty. As secondary outcomes, patients in the transfusion group were compared to patient in the non-transfusion group on the following variables: gender, side of surgery, age, body-mass index (BMI), American Society of Anaesthesiologists (ASA) classification, type of anaesthesia (spinal or general), duration of surgery (minutes), type of arthroplasty (THA, UKA or TKA), patient specific instruments (PSI) usage in TKA, cementation in THA, estimated blood loss, pre- and postoperative Hb levels and length of hospital stay (LoS). In addition, the incidence of postoperative thrombo- embolic events (e.g. deep venous thrombosis/pulmonary embolism, cerebrovascular, myocardial) up to 3 months postoperatively was assessed in both groups. Ethics This studywas performed in compliancewith theHelsinki Declaration of 1975, as revised in 2013 and was studied and approved by the IRB (METC Z, Heerlen, the Netherlands, IRB Nr. METCZ20190123) and conducted in accordance with the guidelines for Good Clinical Practice (GCP).