title: Safety of retransfusing shed blood after local infiltration analgesia in total knee arthroplasty.
abstract: We investigated the safety of LIA (local infiltration analgesia) combined with retransfusion of drained blood. Total knee arthroplasty patients received two peri-articular injections during surgery followed by continuous infusion, both with ropivacaine (567 mg). Ropivacaine plasma concentrations were determined in blood samples taken at 0, 3, 6 and 24 hours postoperatively. The collected shed blood was not retransfused, instead retransfusion was modelled by estimating the cumulative plasma concentrations at 6 hours postoperative. Total and unbound ropivacaine plasma concentrations ranged respectively from 0.08 to 1.9 mg/L and 0.003 to 0.11 mg/L. An average of 13.1 +/- 3.7 mg unbound ropivacaine would have been returned to the patient. The estimated cumulative ropivacaine plasma levels showed that instant retransfusion would have led to plasma levels below 0.26 mg/L. It appears to be safe to transfuse autologous blood in combination with LIA. However, before drawing definite conclusions formal measurement of actual concentrations is required.
authors.affiliation: Department of Orthopaedic Surgery, Medical Center Haaglanden, The Hague, The Netherlands. b.thomassen@mchaaglanden.nl
authors.forename: Bregje J W
authors.initials: BJ
authors.lastname: Thomassen
authors.forename: Laurens
authors.initials: L
authors.lastname: Pool
authors.forename: Rudolf
authors.initials: R
authors.lastname: Van Der Flier
authors.forename: Rudolf
authors.initials: R
authors.lastname: Stienstra
authors.forename: Bastiaan A
authors.initials: BA
authors.lastname: in 't Veld
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000577:Amides; D000698:Analgesia / Q000379:methods*; D000779:Anesthetics, Local; D019645:Arthroplasty, Replacement, Knee; D001804:Blood Transfusion, Autologous / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059408:Pain Management; D010147:Pain Measurement; D011184:Postoperative Period; D011446:Prospective Studies; D000077212:Ropivacaine; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine