Blood transfusion
From IDWiki
Red Blood Cells
- ABO blood type (O, A, B, or AB)
- Most important antigen group
- RhD group (positive or negative)
- Second most important antigen group
- There are more than 30 minor blood group antigens, including Kell (K and k), Kidd (Jk^a^ and Jk^b^), Duffy (Fy^a^ and Fy^b^) and MNS (S and s)
Group & Screen and Crossmatch
- Group and screen
- Group tests recipient for ABO and RhD status
- Screen tests the recipient plasma for unexpected and clinically significant minor antigen incompatibility
- Takes about 45 minutes, but if the screen is positive then can take days to determine which specific antibodies are causing the problem
- Crossmatch confirms that a specific unit of RBCs is safe to give to the recipient
- If screen was negative, an abbreviated crossmatch is done either as immediate spin or as electronic
- If screen was positive, then a full antiglobulin crossmatch is done
Basics
- Each unit is about 300 mL with a hematocrit of 65 to 70%, and raises the recipient's hemoglobin by about 10 g/L
- Usually transfused over 2 hours
- Can do up to 3 or 3.5 hours in elderly over 70 years old, heart failure, LV dysfunction, prior MI, renal dysfunction, or volume overload (usually with concurrent diuretics at the start of the transfusion)
Indications
- Acute blood loss
- Maintain hemoglobin above 70 g/L during active bleeding
- Maintain hemoglobin higher (e.g. above 80 g/L) during active bleeding in patients with:
- Unstable or acute coronary syndrome
- Coronary artery disease
- Uncontrolled or unpredictable bleeding
- Anemia
- Consider for hemoglobin below 70 g/L in stable patients
- Consider for hemoglobin below 80 g/L in patients undergoing orthopedic or cardiac surgery or with cardiovascular disease