Blood Transfusion Alternatives

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Information about Blood Transfusion Alternatives
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Published on February 17, 2009

Author: drpabram

Source: authorstream.com

Alternatives to Standard Blood Transfusion Therapy : Alternatives to Standard Blood Transfusion Therapy Paul S. Ramphal B.Sc., MB.BS., FRCS(Edin), DM(Cardiothor) Cardiothoracic Surgical Service UHWI Why do we transfuse blood? : Why do we transfuse blood? To replace losses of: Circulating volume Oxygen carrying capacity To restore: Metabolic homeostasis To replenish: Normal RBC’s (eg. Sickle cell anaemia) Are Blood Transfusions Safe and Effective? : Are Blood Transfusions Safe and Effective? Relatively speaking, YES All medical procedures weigh risks vs. benefits Millions of people have been saved by receiving blood following major trauma or major surgery For haemophiliacs, blood diseases (eg. SCD) there is currently no alternative What are the problems/challenges of blood transfusion? : What are the problems/challenges of blood transfusion? Blood Transfusion is a tissue transplant Immune reactions (eg. Anaphylaxis) possible, in both directions (host vs. graft, or graft vs. host) Transmission of diseases Acute bacterial, HepB, HepC, HIV, Creutzfeld-Jakob (“mad cow”) Relative Risks of Disease Transmission via Blood Transfusion : Relative Risks of Disease Transmission via Blood Transfusion Hep B 1: 140,000 Hep C 1: 225,000 Hep A 1: 1,000,000 HIV 1: 1,500,000 HTLV 1: 650,000 Bacterial 1: 1,000,000 Malaria 1: 1,000,000 Syphylis 1: 1,000,000 Relative Risk of Mistaken Transfusion : Relative Risk of Mistaken Transfusion Transfusion of mis-matched ABO cells 1: 35,000 ABO incompatible death rate 1:600,000 Transfusion of red cells to wrong patient 1: 17,000 Transfusion of pre-deposited blood to wrong patient 1:20,000 Slide 7: What types of Blood products are Usually transfused, And why? Slide 8: WHOLE BLOOD or PACKED RBC’S USED TO REPLACE BLOOD LOSS DUE TO HAEMORRHAGE WHOLE BLOOD IS ALSO A GOOD VOLUME REPLACEMENT Blood as a Tissue : Blood as a Tissue RBC’s contain hemoglobin, buffers, free radical scavengers 2,3-DPG: Hb interaction allows for the uptake of O2 at high partial pressures and release at low (ie tissues) Blood as Tissue : Blood as Tissue WBC’s, Platelets are essential for the IMMUNE and COAGULATION functions of blood Can we do without blood transfusions altogether? : Can we do without blood transfusions altogether? There are times, such as in major trauma, where only blood is lifesaving Research continues to look for a cheap, efficient, easily stored and transported blood substitute ( it doesn’t exist as yet!!) What about during surgery? Can we avoid/minimize blood transfusions? : What about during surgery? Can we avoid/minimize blood transfusions? Autologous Pre-Donation Meticulous Technique Isovolemic Haemodilution Intra-Operative Blood Retrieval and Re-infusion Autologous Pre-donation : Autologous Pre-donation Patient “donates his/her own blood to himself/herself Several weeks prior to surgery, takes Fe/EPO Then donates a unit a week (usually no more than 3 or 4 units Blood is stored in cold and kept for patient for re-infusion during/after op Isovolemic Haemodilution : Isovolemic Haemodilution 1 to 2 units of patient’s blood withdrawn at the beginning of a procedure Blood volume restored with crystalloid solution Patient bleeds “thin blood” during procedure Gets own blood back at the end Meticulous Technique : Meticulous Technique Careful, precise procedures, using natural tissue planes Planned vascular control Use of clips, ligatures, and cautery where appropriate Newer techniques (harmonic scalpel, LASERs) NB. MINIMIZE BLOOD LOSS “Cell-Saver” : “Cell-Saver” Intra-Operative cell salvage and re-infusion allows for the recovery of blood from the operative field which would otherwise be wasted Saved blood is washed, re-suspended in saline, then bagged and re-infused during or after the procedure A cauterized wound does not bleed : A cauterized wound does not bleed A properly sited wound with appropriate use of cautery should not be a source of ongoing blood loss What about non-blood alternatives? : What about non-blood alternatives? Crystalloids Extensively used Large volumes cause haemodilution Artificial Colloids Dextrans, Hetastarch, Gelatin solutions May cause bleeding problems, allergic reactions at high doses THESE ONLY REPLACE VOLUME Potential Future Directions : Potential Future Directions Perfluorcarbons Hemoglobin solutions Focus is on the ability of a blood substitute to carry oxygen, not on the other functions of blood Perfluorocarbons : Perfluorocarbons Can carry large amounts of dissolved O2 Not H2O soluable, therefore must be emulsified Tend not to release bound O2 easily Difficult to store Perfluorocarbons, cont’d : Perfluorocarbons, cont’d PFC’s carry less O2 under physiological conditions Require high FiO2 to become oxygenated Promising future if problems can be overcome Haemoglobin solutions : Haemoglobin solutions Haemoglobin is a complex protein with properties related to both it’s a.a.sequence and its morphology Free Hb is toxic to the kidneys Haemoglobin solutions, cont’d : Haemoglobin solutions, cont’d Techniques are being developed to micro-encapsulate up to 1 x 106 Hb molecules in artificial red cells or liposomes Recombinant human Hb is the future Conclusions : Conclusions Blood transfusions are relatively safe, Options are necessary, due to the known risks of transfusions, and because of patient preferences (eg. Jehovah’s Witnesses) Avoidance of excessive blood loss is the first step (eg. In surgery) Conclusions, cont’d : Conclusions, cont’d Transfusion protocols now accept lower Hb levels in otherwise fit patients (eg. Hb of 5 or 6 is often well tolerated) Use of novel auto-donation or intra-operative haemodilution techniques has lowered blood use per patient Artificial blood is not yet a reality, but research continues

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