LAM3.18: Transfusion Medicine

Tx of anemia - general cascade (5)

First figure out underlying cause.

Control hemorrhage.

Tx primary dz.

Support tissue O2 delivery.

Reassess and determine if a blood transfusion is needed.

Support tissue O2 delivery by (2)

Restoring/expanding blood volume (IVF).

Nasal O2 insufflation will make very little difference.

Indications for Blood Transfusion (3)

Known acute blood loss of >25% blood volume.

Internal or chronic hemorrhage.

Hemolysis and decreased RBC production.

Blood volume % in LA

8% of BW

Acute blood loss effect on PCV (2)

PCV unchanged initially due to splenic contraction.

If not on IVC, PCV and TP drop in 12-24h w/ acute hemorrhage.

Physiologic adaptation to gradually developing tissue hypoxia generally

masks signs of anemia until the PCV is <15%.

Indications for Blood Transfusion on labs (3)

Severe anemia + signs of poor O2 delivery.

Rapidly decreasing PCV.

Coagulopathy.

Signs of poor O2 delivery (3 - 1st w/ 6)

CS - Increased HR, RR, pale mm, wake pulses, cold extremities, and leth.

Lactate 2-4.

PvO2 <25 (suggests tissue O2 deficit - <20 need to consider transfusion).

Blood transfusion: A single value for a

single variable is NOT enough to trigger a transfusion. It is a compilation of CS + Hx + CP data.

Selecting a donor (5)

free of infectious dz.

Adult and large.

Universal donor for horses - Aa and Qa negative.

Ideally maiden mare or gelding.

Not used as a donor in the past 3wks.

(QH and American saddlebred)

Why bother to do a crossmarch

lifespan of compatible RBCs as compared to incompatible.

Cross-match are less frequently done

in ruminants and camelids, but reco if multiple transfusions.

Major cross-match (2)

Donor RBCs w/ serum from recipient.

need source of complement in horses.

Minor crossmatch

RBC from recipient w/ serum from donor.

Transfusion Rxn CS (7)

Increased HR, RR, Temp.

M. fasciculations.

Urticaria.

D.

Resp distress.

Collapse.

Hemolysis.

Tx for transfusion rxn (3)

Stop transfusion or slow rate.

Diphenhydramine IV or IM OR Banamine IV.

Epinephrine for anaphylaxis.

Target PCV

15-20% - go for 20%

Blood volume calculation in L

P' BW 0.08 ((desired PCV-recipient PCV)/donor PCV)

Safe donation volume from adults

Safe donation total equation

0.016 * donor BW