Perioperative transfusion threshold for red blood cells
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PhD Abstract Perioperative transfusion threshold for red blood cells Kamilla Nielsen Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark PhD dissertation abstract Background: Blood transfusions have been used for nearly a century to maintain oxygen delivery to the body during and after surgery. The appropriate level of haemoglobin concentration at which to administer allo- genic transfusion of red blood cells (RBC) is still not well established. Method: This thesis is based upon one observational study and two randomised trials investigating perioperative transfusion thresholds for RBC. In the randomised trials were tissue oxygenation during spinal surgery and postoperative ambulation after hip revision surgery investigated in patients randomised to receive RBC transfusion at either a liberal transfusion threshold of 5.5 mmol/l or a restrictive transfusion threshold of 4.5 mmol/l. The observational study was a secondary analysis of postoperative complications in patients undergoing abdominal surgery who had received different rates of transfusion compared to blood loss. Results: A liberal transfusion strategy was not associated with improved subcutaneous tissue oxygenation in patients undergoing major spinal surgery. Patients undergoing hip revision surgery who had received a liberal transfusion strategy performed the Timed Up and Go-test faster than patients who had received a restrictive strategy, but the clinical relevance of this study is questionable. A higher rate of transfusion compared to blood loss was not significantly associated with an increased risk of postoperative surgical site infection, although patients receiving a more liberal transfusion practice seem to have a tendency towards increased risk of pneumonia, and they were more often admitted to the intensive care unit. Conclusion: According to these studies is a liberal transfusion strategy for RBC not recommended. B lood transfusions have been used for nearly a century to maintain oxygen delivery to organs and tissues of the body. The appropriate level of haemoglobin concentration (Hb) at which to administer allogenic transfusion of red blood cells (RBC) during and after surgery is still not well established, and RBC transfu- sions are associated with side effect despite recent developments in modern transfusion medicine. We conducted three studies with the following hypotheses: 1. A higher level of haemoglobin would improve subcutaneous tissue oxygen tension during spinal fusion with instrumentation. 2. A higher transfusion threshold would decrease the time it takes to perform the Timed Up and Go-test after hip revision surgery. 3. A more liberal transfusion practice would be associated with a higher risk of surgical site infection. Two were randomised clinical trials (studies 1 and 2), and one was a secondary analysis of a previous randomised trial (study 3). Both of the randomised trials compared a restrictive transfusion threshold of Supervisors: Professor, Lars S. Rasmussen, MD, PhD, DMSc, Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet; Professor, Benny Dahl, MD, PhD, DMSc, Department of Orthopaedic Surgery, Spine Section, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet. Evaluation committee: Kai Lange, MD, DMSc, Department of Anaesthesia, Copenhagen University Hospital, Hillerød, Ebbe Stender Hansen, MD, DMSc, Department of Orthopaedic Surgery, Aarhus University Hospital; Professor, Anders Larson, MD, DMSc, Department of Anesthe- siology and Intensive Care, Uppsala University, The oral defense took place at Rigshospitalet the 13 October, 2011. Acta Anaesthesiol Scand 2013; 57: 677–678 Printed in Singapore. All rights reserved © 2013 The Acta Anaesthesiologica Scandinavica Foundation Published by Blackwell Publishing Ltd. ACTA ANAESTHESIOLOGICA SCANDINAVICA doi: 10.1111/aas.12088 677
Transcript of Perioperative transfusion threshold for red blood cells
PhD Abstract
Perioperative transfusion threshold for red blood cells
Kamilla Nielsen
Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
PhD dissertation abstractBackground: Blood transfusions have been used for nearly a century to maintain oxygen delivery to the bodyduring and after surgery. The appropriate level of haemoglobin concentration at which to administer allo-genic transfusion of red blood cells (RBC) is still not well established.
Method: This thesis is based upon one observational study and two randomised trials investigatingperioperative transfusion thresholds for RBC. In the randomised trials were tissue oxygenation during spinalsurgery and postoperative ambulation after hip revision surgery investigated in patients randomised toreceive RBC transfusion at either a liberal transfusion threshold of 5.5 mmol/l or a restrictive transfusionthreshold of 4.5 mmol/l. The observational study was a secondary analysis of postoperative complications inpatients undergoing abdominal surgery who had received different rates of transfusion compared to bloodloss.
Results: A liberal transfusion strategy was not associated with improved subcutaneous tissue oxygenationin patients undergoing major spinal surgery. Patients undergoing hip revision surgery who had received aliberal transfusion strategy performed the Timed Up and Go-test faster than patients who had received arestrictive strategy, but the clinical relevance of this study is questionable. A higher rate of transfusioncompared to blood loss was not significantly associated with an increased risk of postoperative surgical siteinfection, although patients receiving a more liberal transfusion practice seem to have a tendency towardsincreased risk of pneumonia, and they were more often admitted to the intensive care unit.
Conclusion: According to these studies is a liberal transfusion strategy for RBC not recommended.
Blood transfusions have been used for nearly a century to maintain oxygen delivery to organs and tissuesof the body. The appropriate level of haemoglobin concentration (Hb) at which to administer allogenic
transfusion of red blood cells (RBC) during and after surgery is still not well established, and RBC transfu-sions are associated with side effect despite recent developments in modern transfusion medicine. Weconducted three studies with the following hypotheses:
1. A higher level of haemoglobin would improve subcutaneous tissue oxygen tension during spinal fusionwith instrumentation.
2. A higher transfusion threshold would decrease the time it takes to perform the Timed Up and Go-test afterhip revision surgery.
3. A more liberal transfusion practice would be associated with a higher risk of surgical site infection.
Two were randomised clinical trials (studies 1 and 2), and one was a secondary analysis of a previousrandomised trial (study 3). Both of the randomised trials compared a restrictive transfusion threshold of
Supervisors: Professor, Lars S. Rasmussen, MD, PhD, DMSc, Department of Anaesthesia, Centre of Head and Orthopaedics, CopenhagenUniversity Hospital, Rigshospitalet; Professor, Benny Dahl, MD, PhD, DMSc, Department of Orthopaedic Surgery, Spine Section, Centre of Headand Orthopaedics, Copenhagen University Hospital, Rigshospitalet.Evaluation committee: Kai Lange, MD, DMSc, Department of Anaesthesia, Copenhagen University Hospital, Hillerød, Ebbe Stender Hansen,MD, DMSc, Department of Orthopaedic Surgery, Aarhus University Hospital; Professor, Anders Larson, MD, DMSc, Department of Anesthe-siology and Intensive Care, Uppsala University, The oral defense took place at Rigshospitalet the 13 October, 2011.
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Acta Anaesthesiol Scand 2013; 57: 677–678Printed in Singapore. All rights reserved
© 2013 The Acta Anaesthesiologica Scandinavica FoundationPublished by Blackwell Publishing Ltd.
ACTA ANAESTHESIOLOGICA SCANDINAVICA
doi: 10.1111/aas.12088
677
4.5 mmol/l to a liberal transfusion threshold of 5.5 mmol/l. In the secondary analysis, a restrictive transfu-sion practice in relation to blood loss was compared to a liberal transfusion practice.
Subcutaneous oxygenation was not improved significantly in patients transfused at a more liberal trans-fusion threshold during major spinal surgery (study 1).
Patients transfused more liberally performed the Timed Up and Go-test at a mean of 14.5 s (P = 0.02) fasterthan patients more restrictively transfused, but the clinical relevance is questionable (study 2). The algorithmof transfusion was difficult to adhere to in both studies 1 and 2.
A higher rate of transfusion of RBC in relation to blood loss was not associated with an increased risk ofsurgical site infection in patients undergoing abdominal surgery but an increased risk of admittance to theintensive care unit with an odds ratio of 7.3 (P = 0.02) was found. A tendency towards an increased risk ofpneumonia was found (study 3).
After conducting the studies, we concluded that:
1. A liberal transfusion strategy was not associated with improved subcutaneous tissue oxygenation inpatients undergoing major spinal surgery.
2. A liberal transfusion strategy decreases the time it takes to perform Timed Up and Go-test after hiprevision surgery but the clinical relevance is questionable.
3. A higher rate of transfusion compared to blood loss is not significantly associated with an increased riskof postoperative surgical site infection, although patients receiving a more liberal transfusion practiceseem to have a tendency towards increased risk of pneumonia and are more often admitted to theintensive care unit.
Future research should aim at assessing the connection of perioperative transfusion thresholds concerningoxygenation, ambulation and complications of RBC transfusions in a clinical setting. The thesis is based onthe papers listed below.
Kamilla Nielsen
I. Nielsen K, Dahl B, Johansson PI, Henneberg SW, Rasmussen LS. Intraoperative transfusion threshold and tissue oxygenation – arandomized trial. Transfusion Medicine 2012; 22: 418–25.
II. Nielsen K, Johansson PI, Dahl B, Wagner M, Frausing B, Børglum J, Jensen K, Stürup J, Hvolris J, Rasmussen LS. Perioperativetransfusion threshold and ambulation after revision hip surgery – a randomized trial. Manuscript submitted.
III. Nielsen K, Meyhoff CS, Johansson PI, Rasmussen LS. Transfusion practice and complications after laparotomy – an observationalanalysis of a randomized clinical trial. Vox Sanguinis. 2012; 103: 294–300.
PhD Abstract
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