Transfusion

Question 1

Maximum allowable blood loss equation

Answer 1

MABL= EBV x [(hct initial- hct acceptable)/hct average]

Question 2

What is Hetastarch?

Answer 2

• Hetastarch is a synthetic colloid solution
• Reported to decrease factor VIII:C levels and interfere with clot formation
• Recommended dosage <20ml/kg

Question 3

What factors does cyroprecipitate contain?

Answer 3

• Fibrinogen, vWF, VIII, XIII
• 1 unit has 80-145 U factor VIII and 250mg fibrinogen
• 1 unit = 10mL

Question 4

Coagulation factors including FFP and platelets should be administered after how many PRBCs?

Answer 4

FFP after 12. Platelets after 20.

Question 5

What factors decrease after massive transfusion?

Answer 5

Factors 5 and Fibrinogen the most. Factor 8 as well (but less bc released from endothelium during surgical stress)

Question 6

What is the incompatibility risk of fully crossmatched blood?

Answer 6

0.05%

Question 7

Most common blood group and RH status?

Answer 7

O blood in 45% white and 50% blacks. 85% of humans are Rh positive.

Question 8

Relative contraindications to autologous blood donation?

Answer 8

HOCM, severe AI, anemia, recent MI, severe left main disease

Question 9

What is a normal extraction ratio while

resting?

Answer 9

25% in a healthy adult. May increase to 80% during max exercise in athletes.

Question 10

Why does the curve right shift in anemia?

Answer 10

Increased 2,3 DPG is made by the tissue to facilitate unloading of oxygen.

Question 11

What does cryoprecipitate contain?

Answer 11

250mg Fibrinogen, VWB, Factor 8, Factor 13, and fibronectin.

Question 12

What does FFP contain?

Answer 12

Fibrinogen, all procoagulants and fibronectin. But much less per unit volume than cryo!

Question 13

How much will one unit of platelets increase platelet count?

Answer 13

5,000- 8,000

Question 14

Hct of packed reds?

Answer 14

70-80%

Question 15

HIV risk from transfusion? Hep B risk? Hep C risk?

Answer 15

HIV: 1 in 2,000,000. The window is now 10 days.
Hep C: 1 in 1,900,000
Hep B: 1: 200,000

Question 16

How is a type and screen done?

Answer 16

Pt’s RBC are tested with serum known to have antibodies to A & B. Confirmed by testing pt’s serum against RBC’s with known antigen. Antibody screen is done by mixing pt’s serum with known antigenic compositions (indirect coombs test and takes 45 mins).

Question 17

How is a type and crossmatch done?

Answer 17

Mix donor RBC with recipient serum.

Question 18

What is the incidence of a serious hemolytic rxn with a negative antibody screen (without crossmatch)?

Answer 18

~1: 10,000 or 0.06% (depending of what you read)

Question 19

What is the benefit of a crossmatch?

Answer 19

Assures optimal safety, detects less common antibodies, confirms ABO Rh and detects low titer antibodies.

Question 20

What is donated blood tested for?

Answer 20

Hep B, Hep C, Syphilis, HIV, West nile virus, Chagas, HTLV

Question 21

How long can blood be stored in CPDA-1?

Answer 21

~35 days (C=citrate, P=phosphate, D=dextrose, A=adenosine)

Question 22

How long can platelets be stored and at what temperature?

Answer 22

5 days at 20-24 degrees celsius.

Question 23

What are the most labile clotting factors in plasma?

Answer 23

V and VIII

Question 24

How long do transfused platelets survive?

Answer 24

1-7 days

Question 25

Each unit of FFP will increase clotting factors by how much?

Answer 25

2-3%

Question 26

How long can FFP be stored and at what temp?

Answer 26

1 year at -18 degrees celsius

Question 27

Anaphylactic rxn to blood are usually due to?

Answer 27

IgA deficiency. Occurs at a rate of 1: 150,000

Question 28

What are the complications of massive transfusion?

Answer 28

Coagulopathy (dilutional thrombocytopenia), citrate toxicity, hypothermia, acid base balance (citrate and lactic acid metabolized to bicarb in normal liver), serum potassium

Question 29

What is the physiologic compensation for isovolemic hemodilution/chronic anemia?

Answer 29

Increase CO secondary to increase in SV (decrease SVR and decrease viscosity), improved microcirculation, increase tissue extraction (increase 2,3 DPG and shift curve to the right).