MINIMIZING INTRA- OP TRANSFUSION REQUIREMENTS DR. NYAMARI FACILITATOR: DR. BHOYYO KIBET

RATIONALE To minimize hazards associated with blood transfusion Hazards include infection, immunologic reactions, hypothermia, volume overload, dilutional coagulopathy, Conservation and optimal use of blood resources due to perennial blood shortage To improve outcomes in patients objecting blood transfusion for religious/personal reasons

TRANSFUSION THRESHOLD

STRATEGIES Patient optimization Minimization of blood losses Alternatives to allogeneic blood

PATIENT OPTIMIZATION Correction of anemia, thrombocytopenia Optimize hemostatic function; stopping anti-coagulant therapy early, NSAIDs, correction of coagulopathies Minimizing diagnostic phlebotomy Pre-operative Autologous Donation(PAD)

PAD This involves a patient scheduled for elective surgery donating blood prior to surgery Hb ≥ 11g/dl or HCT ≥33% (AABB standards) Donation done weekly at 10.5ml/kg Efficacy is dependent on the patient’s intrinsic increase in erythropoiesis Endogenous erythropoietin response is sub optimal resulting in only 11% expansion of RBC volume Recombinant erythropoietin and daily iron supplements aid.

PAD ADVANTAGES Limits transfusion transmitted diseases Prevents red cell alloimmunization Provides compatible blood Provides patient reassurance

PAD DISADVANTAGES Doesn’t reduce risk of contamination May result in wastage of blood not transfused(5%) Risk of perioperative anemia More expensive

PAD CONTRAINDICATIONS Evidence of infection Scheduled surgery for aortic stenosis Unstable angina, MI, CVA, Cyanotic heart dx Uncontrolled hypertension

MINIMIZING BLOOD LOSS Acute Normovolemic Hemodilution(ANH) Intra-operative cell salvage Surgical technique Anesthetic technique Pharmacologic manipulation

ANH Removal of whole blood from a patient while restoring the circulating volume with acellular fluid shortly before significant blood loss End point is a Hct of 27%-33% Blood collected in standard blood bags, stored at room temperature Re-infused during surgery after major blood loss ceases( within 8hrs) Re-infusion is done in reverse order.

ANH The chief benefit is the reduction of RBC losses. Concomitant decrease in arterial oxygen capacity Compensatory increase in Cardiac output and reduction in peripheral resistance.

ANH CRITERIA Likelihood of transfusion exceeds 10% Absence of cardiac, hepatic or renal dx Absence of hypertension Absence of infection

ANH v/s PAD ANHPAD LESS COSTLYEXPENSIVE DECREASED BLOOD WASTAGESIGNIFICANT BLOOD WASTAGE MINIMAL CONTAMINATIONHIGHER RISK OF CONTAMINATION MINIMAL CLERICAL ERRORSHIGHER RISK OF CLERICAL ERRORS

INTRA-OP BLOOD SALVAGE Involves the collection of blood from the surgical field into a cell salvage device. The cell salvage device: a.Filters the collected blood(40nm filters) i.e. bone fragments, tissue debris b.Anti-coagulates the blood c.Separates RBCs from other cellular and liquid elements d.Washes salvaged RBCs extensively with saline The RBCs are then re-infused suspended in saline

CELL SALVAGE MACHINE

INTRA-OP BLOOD SALVAGE INDICATIONS Aortic reconstruction Spinal instrumentation Joint arthroplasty Liver transplantation Resection of A-V malformations Trauma patients

INTRA-OP BLOOD SALVAGE CONTRAINDICATIONS Infection Malignant cells Urine and bowel contents in operating field Amniotic fluid Procoagulant material used in surgical field

INTRA-OP BLOOD SALVAGE COMPLICATIONS Massive air embolism Dilutional coagulopathy Nephrotoxicty by free Hb ( limit suction pressures to 150mmHg)

ANAESTHETIC TECHNIQUE Maintainance of normothermia Use of regional anesthesia when possible e.g. TJR surgery Patient positioning Avoiding high intra-thoracic pressures Controlling blood pressure Permissive hypotension Controlling and maintaining a normal pCO2

SURGICAL TECHNIQUE Meticulous surgical hemostasis Use of diathermy, laser scapel Use of tourniquet where applicable Minimally invasive procedures if possible

PHARMACOLOGIC AGENTS Serine protease inhibitors e.g. Aprotinin that are direct plasmin inhibitors Lysine analogues e.g. Tranexamic acid that inhibit conversion of plasminogen to plasmin Desmopressin that stimulates the release of vWF promoting primary haemostasis Recombinant activated factor VIIa Fibrin glue

ALTERNATIVES TO BLOOD Substances used to mimic and fulfill functions of biological blood especially oxygen ‘carrying’ Hemoglobin based oxygen carriers Perfluorocarbon based oxygen carriers

CONCLUSION Adhere to protocols on transfusion of blood and its products Where protocols are non-existent, develop the protocols Pre-operative assessment and work-up of patients

REFERENCES Miller’s anesthesia, 7 th edition Autologous Transfusion, Recombinant Factor VIIa, and Bloodless Medicine Lawrence T. Goodnough, Terri G. Monk Clinical Anesthesia, 6 th Edition Hemostasis and Transfusion Medicine Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; Stock, M. Christine