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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Blood Transfusion: pRBCs


- See: Transfusion Therapy and  Blood Prod Menu

- Indications for Transfusion:

- Transfusion Technique:

     - maximum time over which blood products can be administered is 4 hrs for 1 unit because of danger of bacterial proliferation & RBC hemolysis;
             - if slower infusion rate is required, half of the unit may be infused while other portion remains refrigerated in the blood bank;
     - if flow rate is interrupted for >30 minutes, unit must be discarded;
     - blood should be administered thru 170 um filters to prevent infusion of macroaggregates of fibrin and debris as well as leukocytes;
     - patients should be observed for the first 5-10 min of a transfusion and then examined frequently for signs of fluid overload and other adverse reactions;
     - emergent transfusion:
             - in most cases an Rh type and screen takes 10 minutes and is safer than using O negative blood;


- Characteristics of pRBC;
    - approx 300 +/- 25 mL
    - hematocrit: 70 +/- 5%;
    - one unit of pRBCs should increase hemoglobin by approximately 1 gm/dl;
    - citrate is used as an anticoagulant in blood products during plasmapheresis;
    - citrate is converted to bicarb by liver & causes metabolic alkalosis;
    - induction of a metabolic alkalosis may produce an abrupt increase in the hemoglobinn oxygen affinity;
    - w/ transfusion actual amount of potassium administered is approx between 5.2 to 6.6 mEq per unit of pRBC;
    - since the mean age of blood administered to trauma pts is 13.5 days (and not 35 to 49 days - expiratio date of blood), the actual
             amount of potassium administered per unit may be only 1 to 3 mEq;
    - w/ massive transfusion hypokalemia is more frequently encountered than hyperkalemia;- this may be also due to alkalosis (from citrate)

- DPG:
    - w/ blood that is stored in acid citrate dextrose (ACD) solution for upto to three weeks is based on the survival of at least 70% of cells in recipients circulation;
    - during 3 week period, there is decline in  2-3 disphosphoglycerate (DPG) and a progressive increase in hemoglobin oxygen affinity (left shift of
               the oxygen dissociation curve);
    - after transfusion DPG levels require 24 hours or longer to return nl;

- Complications of blood transfusion:
    - transmission of disease:
    - citrate toxicity:

         - can be prevented or its effects minimized by the administration of Ca;
         - historically 1gm of CaCl has been given for every four units of blood administered until such time as the pt is normothermic, euvolemic, and is
                 known to have reasonably normal hepatic function;
         - if Ca gluconate is used, dose must be 4 times greater than w/ CaCl;
         - improved approach is to measure the ionized calcium level



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, December 14, 2011 3:39 pm