Rationale of Blood Transfusion

1. RATIONALE OF BLOOD
TRANSFUSION
Hemant Ojha

2. Overview
• Basic Concepts – Oxygen Delivery & Utilization
• Impact of Anemia – Mortality & Morbidity
• Risks of Complications of Transfusion
• Approach Considerations – The Clinical Compromise

3. BASIC CONCEPTS – Oxygen Delivery
• Oxygen delivery (DO2) = Cardiac output (Q) x Arterial oxygen content (CaO2)
• Heart Rate (HR)
• Stroke Volume (SV)
• SaO2 × Hb × O2 combining
capacity of Hb)
+
• (O2 solubility × PaO2)

4. BASIC CONCEPTS – Oxygen Utilization
• Oxygen consumption (VO2) = DO2 x O2 extraction
• Heart Rate (HR)
• Stroke Volume (SV)
• SaO2 × Hb × O2 combining
capacity of Hb)
+
• (O2 solubility × PaO2)

5. BASIC CONCEPTS – Oxygen Delivery & Utilization

6. BASIC CONCEPTS – Oxygen Delivery & Utilization
• Wilkerson DK, Rosen AL, Gould SA, Sehgal LR, Sehgal HL, Moss GS. Oxygen extraction ratio: a valid indicator
of myocardial metabolism in anemia. J Surg Res. 1987 Jun;42(6):629-34.

7. RISKS OF ANEMIA – Mortality & Morbidity
Mortality1
• 7.1 to 8.0 – 0.9 %
• 5.1 to 7.0 – 9.2 %
• 3.1 to 5.0 – 26.7 %
• ≤3.0 – 62.1 %
• No benefit with aggressive correction2
1. Carson JL, Noveck H, Berlin JA, Gould SA. Mortality and morbidity in patients with very low
postoperative Hb levels who decline blood transfusion. Transfusion 2002; 42:812.
2. Carson JL, Stanworth SJ, Roubinian N, et al. Transfusion thresholds and other strategies for guiding
allogeneic red blood cell transfusion. Cochrane Database Syst Rev 2016; 10:CD002042.

8. RISKS OF TRANSFUSION
Immune Mediated Non Immune Mediated
Acute Delayed Acute Delayed
• Hemolytic • Hemolytic • Septic • Infection
• Febrile reactions • Purpura • TACO • Iron overload
• Urticaria • GVHD • Hyperkalemia
• Anaphylaxis • Hypocalcemia

9. APPROACH CONSIDERATIONS– The Clinical Compromise
• Apart from hemoglobin levels, clinical status, comorbidities to be
considered.
• Various guidelines and recommendations.
• Restrictive thresholds for most clinically stable patients.

10. APPROACH CONSIDERATIONS– The Clinical Compromise

11. APPROACH CONSIDERATIONS– The Clinical Compromise

12. “Blood transfusion is like marriage: it should not be entered upon
lightly, unadvisedly or wantonly or more often than is absolutely
necessary.”
— R. Beale
Beale RJ. The rational use of blood. Aust N Z J Surg. 1976;46:309–313.
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