title: Development and validation of a novel tool to estimate peri-operative blood loss.
abstract: Surgical blood loss predicts peri-operative outcomes. We have developed and validated Blood Loss Scores to estimate peri-operative blood loss during major abdominal surgery. Surgical blood loss and changes in haemoglobin concentration were recorded intra- and postoperatively for 48 h in 100 patients undergoing radical prostatectomy. Data from the first group (n = 50) were used to derive the Blood Loss Scores which were validated against the data from a second group (n = 50) at three time points (immediately postoperative and 24- and 48-h later). The score, taking into account suction fluid volume and haemoglobin concentration, explained more of the variance in the measured blood loss than the experts' assessment (77% vs 54%, p = 0.05) or the change in haemoglobin concentration (77% vs 11%, p < 0.0001). Addition of the change in haemoglobin concentration improved the estimate for the 24- and 48-h postoperative Blood Loss Scores to explain 78% and 80% of the variance of measured blood loss.
authors.affiliation:  Resident, Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Stahl
authors.affiliation:  Chief Anaesthetist, Professor, Department of Anaesthesiology, Klinik für Anästhesiologie, Intensiv- und Schmerztherapie, Klinikum Essen-Mitte, Essen, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Groeben
authors.affiliation:  Chief Urologist, Professor, Department of Urology, Klinik fuer Urologie, Klinikum Essen-Mitte, Essen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Kroepfl
authors.affiliation:  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Centre, Boston, USA.
authors.forename: S
authors.initials: S
authors.lastname: Gautam
authors.affiliation:  Assistant Professor, Harvard Medical School, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, USA.
authors.forename: M
authors.initials: M
authors.lastname: Eikermann
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000517:prevention & control / Q000706:statistics & numerical data*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods* / Q000706:statistics & numerical data; D011446:Prospective Studies; D011468:Prostatectomy; D015203:Reproducibility of Results; D013396:Suction
chemical_list: D006454:Hemoglobins