Transfusion in special clinical circumstances

Question 1

ASPEN syndrome

Answer 1

• adverse reaction after exchange transfusion in sickle cell disease
• ASPEN (association of sickle cell disease, priapism, exchange transfusion, and neurologic events)
  
  • headache
  • seizures
  • altered mental status
  • hemiparesis
  • above occur within 11 days of exchange transfusion

Question 2

Indications for emergency transfusion/exchange transfusion in sickle cell disease

Answer 2

• stroke
• retinal artery occlusion
• splenic sequesteration crisis
• actue chest syndrome
• aplastic crisis
• priapism treated medically unless unsuccessful, then transfused

Question 3

Indications for elective chronic transfusion in sickle cell

Answer 3

• children with abnormal flow velocity by transcranial Doppler for stroke prevention
• progressive renal or cardiopulmonary disease
• complicated pregnancy
• usual target HbS is <30% in children and < 50% in adults

Question 4

Alloimmunization in multiply transfused sickle cell patients

Answer 4

• with nonphenotypically matched blood, rate of alloimmunization per transfusion is 3%, overall rate of alloimmunization is between 19%-47%
• most common alloantibodies
  
  • K
  • C
  • E
  • Fy^a
  • Jk^b
• with blood matched for Cc, D, Ee, Fy^a, and Jk^b alloimmunization rate per transfusion is 0.5%

Question 5

Class I hemorrhage

Answer 5

• loss of <15% blood volume (<750 ml), usually asymptomatic or has mild tachy

Question 6

Class II hemorrhage

Answer 6

• loss of 15-30% of blood volume (750-1500 ml)
• tachycardia, tachypnea, anxiety, clammy skin
• only fluid resuscitation is required usually

Question 7

Class III hemorrhage

Answer 7

• loss of 30-40% of blood volume (1500-2000 ml)
• hypotension
• tachycardia
• tachypnea
• pallor
• AMS
• usually need transfusion

Question 8

Class IV hemorrhage

Answer 8

• loss of > 40% of blood volume (>2000 ml)
• shock - thready pulse and risk of death
• fluid resuscitation needed as well as transfusion

Question 9

Principles of fluid resuscitation

Answer 9

• fluid resuscitation comes first
  
  • red blood cells initiated once administration of fluid >30 ml/kg of body weight (~2 L)
• all fluids have capacity to impair homeostasis, mainly through hemodilution

Question 10

Emergency release

Answer 10

• release of blood based on history of blood type is forbidden
• release of blood based on forward type only is not good
• physician must sign release stating the blood was not fully tested for compatibility within 24 hours (not required at time of release of blood)
• blood product label must indicate that compatibility testing was not completed
• consider giving Rh Ig if Rh+ blood given to woman of child-bearing age
• when patient has known anti E or anti C, Rh- negative blood should be given

Question 11

Principles of Rh Ig administration for Rh-incompatible blood products

• timing
• dose
• how do you administer
• contraindicated when?

Answer 11

• RhIg should be given within 72 hours of transfusion
• IV RhIg dosage: 90 IU/ 1 ml of transfused Rh+ RBCs /2ml transfused whole blood
• administer entire dose of IV RhIg into vein over 3-5 minutes
• IV RhIg is discouraged for transfusion of quantity of Rh+ blood that excceds 20% of blood volume as this may cause severe hemolysis

Question 12

Massive transfusion definition

Answer 12

• transfused total blood volume (10-15 units of PRBC in a 70 kg patient)
• 1/2 of patient’s blood voume replaced within 3 hours
• >4 units of RBCs are transfused within 4 hours

Question 13

Complications of massive transfusion

Answer 13

1. transfused blood does not immediately have the O2 carrying capacity of innate blood because of depletion of 2,3 DPG and ATP resulting in a shift of the O2 dissociation curve to the left (impaired release of O2)
2. lower pH
3. increase K
4. lower body temperature
5. increase free Hgb
6. coagulopathy 2/2 coagulation factors and platelet consumption, dysfunction, or dilution
   
   • thus the need for MTP in which platelets and plasma are also given with RBCs to prevent this