MINIMIZING INTRA-OP TRANSFUSION REQUIREMENTSDR. NYAMARIFACILITATOR: 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• ABLEBV• EBV Premature neonates 95mL/kgFull term neonate 85mL/kgInfants 80mL/kgAdult men 75mL/kg Adult women 65mL/kg

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 PADANH PAD

LESS COSTLY EXPENSIVE

DECREASED BLOOD WASTAGE SIGNIFICANT BLOOD WASTAGE

MINIMAL CONTAMINATION HIGHER RISK OF CONTAMINATION

MINIMAL CLERICAL ERRORS HIGHER 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 bloodc. Separates RBCs from other cellular and liquid elementsd. 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, 7th edition Autologous Transfusion,

Recombinant Factor VIIa, and Bloodless Medicine Lawrence T. Goodnough,Terri G. Monk

• Clinical Anesthesia, 6th Edition Hemostasis and Transfusion Medicine Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; Stock, M. Christine