Blood transfusion detailed for surgery bailey and love

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Blood Transfusion in Surgery - Bailey & Love's Short Practice of Surgery (28th Edition)

1. Historical Background

Blood transfusion has become commonplace since the first successful transfusion in 1818. Key milestones include:

Year	Event
1665	Richard Lower performs first successful canine transfusions
1818	James Blundell performs the first successful human transfusion (postpartum haemorrhage)
1901	Karl Landsteiner discovers the ABO system
1914	Albert Hustin performs first non-direct transfusion using sodium citrate as anticoagulant
1926	British Red Cross institutes the first blood transfusion service in the world
1939	Rhesus system identified as major cause of transfusion reactions

Despite falling risks of reactions and infections, it is now recognised that transfusion of heterologous blood carries an immunological price - increased morbidity and decreased survival in trauma and malignancy patients. Blood supplies are limited, so use must be judicious.

2. Blood Donation and Screening

In the UK, up to 450 mL is drawn, a maximum of 3 times per year
Each unit is tested for: Hepatitis B, Hepatitis C, HIV-1, HIV-2, and Syphilis
All donations are leukodepleted (precaution against variant Creutzfeldt-Jakob disease and to reduce immunogenicity)
ABO and Rhesus D blood groups are determined, plus screening for irregular red cell antibodies
Blood is then processed into subcomponents

3. Blood and Blood Products

Whole Blood

Rarely available in civilian practice (seen as inefficient use of limited resource)
Has significant advantages over packed cells - coagulation factor rich and if fresh, maintains haemostatic function
Currently under re-evaluation, particularly in trauma/military settings ("walking blood banks")

Packed Red Cells (pRBCs)

Spun-down, concentrated red blood cells
Each unit: approximately 330 mL, haematocrit 50-70%
Stored in SAG-M (saline-adenine-glucose-mannitol) solution
Shelf life: 5 weeks at 2-6°C
(Older CPD [citrate-phosphate-dextrose] storage: shelf life only 2-3 weeks)

Fresh Frozen Plasma (FFP)

Rich in coagulation factors
Stored at -40°C to -50°C, shelf life: 2 years
First-line therapy for coagulopathic haemorrhage
Rhesus D-positive FFP may be given to a Rh(D)-negative woman, but Rh-D immunisation should be considered with large volumes (red cell fragments present)

Cryoprecipitate

Supernatant precipitate of FFP
Rich in: fibrinogen, Factor VIII, Factor XIII
Stored at -30°C, shelf life: 2 years
Indications: low-fibrinogen states, Factor VIII deficiency

Platelets

Supplied as pooled platelet concentrate: ~250 × 10⁹/litre
Stored on special agitator at 20-24°C, shelf life only 5 days
Given for: thrombocytopenia or platelet dysfunction in bleeding/surgical patients
Patients on clopidogrel undergoing major surgery may require near-continuous platelet infusion
DDAVP (desmopressin/arginine vasopressin analogue) has been used for antiplatelet therapy patients, though with limited success

Prothrombin Complex Concentrates (PCC)

Highly purified concentrates prepared from pooled plasma
Contain Factors II, IX, X (and sometimes VII in 4-factor PCCs)
Used in reversal of anticoagulant-related coagulopathy

4. Blood Groups and Cross-Matching

ABO System

The system has 3 allelic genes (A, B, O) controlling synthesis of enzymes that add carbohydrate residues to cell surface glycoproteins.

Phenotype	Genotype	Antigens	Antibodies	Frequency (UK)
O	OO	O	Anti-A, Anti-B	46%
A	AA or AO	A	Anti-B	42%
B	BB or BO	B	Anti-A	9%
AB	AB	A and B	None	3%

Group O = Universal donor (no antigens to provoke reaction)
Group AB = Universal recipient (no circulating antibodies)

Rhesus System

The Rh(D) antigen is strongly antigenic; present in ~85% of UK population
Anti-D antibodies are not naturally occurring but can be stimulated by Rh+ red cell transfusion or delivery of Rh(D)-positive baby
Acquired anti-D antibodies can cross the placenta in a Rh(D)-negative mother and cause haemolytic anaemia / hydrops fetalis in a Rh(D)-positive fetus

Cross-Matching Procedures

Procedure	Detail
Group and save	Blood grouped, serum saved for 5-7 days for immediate cross-match if needed
Full cross-match	Takes ~45 min; donor cells mixed with recipient serum to detect incompatibility
Type and screen	Identifies recipient ABO/Rh type and screens for antibodies
Emergency (uncross-matched)	Group O Rh(D)-negative "universal donor" blood used in life-threatening emergencies

5. Indications for Blood Transfusion

Blood transfusion is indicated when the oxygen-carrying capacity of blood falls to a level that threatens adequate tissue oxygenation. Indications include:

Acute haemorrhage with haemodynamic compromise
Symptomatic anaemia (fatigue, dyspnoea, angina)
Pre-operative optimisation of severe anaemia
Perioperative blood loss sufficient to impair tissue perfusion

6. Transfusion Trigger

The decision to transfuse should not be made on haemoglobin level alone. The "transfusion trigger" concept accounts for:

The patient's physiological reserve
Presence of cardiorespiratory disease
Signs of tissue hypoxia (tachycardia, lactate rise, ST changes)
Expected ongoing losses

General surgical thresholds:

Hb <70 g/L - transfusion usually indicated in most patients
Hb 70-100 g/L - decision guided by clinical context and symptoms
Hb >100 g/L - transfusion rarely indicated
Patients with cardiovascular disease may require a higher trigger (Hb ~80-100 g/L)

A restrictive transfusion strategy (trigger ~70 g/L) is generally non-inferior to liberal strategies in most surgical patients.

7. Transfusion Reactions

Acute Reactions (during or within 24 hours)

Type	Mechanism	Features
Acute haemolytic reaction	ABO incompatibility (clerical error)	Fever, rigors, back/loin pain, haemoglobinuria, shock, DIC - FATAL if not stopped immediately
Febrile non-haemolytic reaction	Leukocyte antibodies	Fever, rigors, mild hypotension - most common reaction
Allergic/anaphylactic	IgE-mediated (IgA deficiency)	Urticaria, bronchospasm, anaphylaxis
Transfusion-related acute lung injury (TRALI)	Donor antibodies vs. recipient leukocytes	Acute pulmonary oedema, hypoxia within 6 hours
Bacterial contamination	Usually platelets (stored at room temp)	Rapid-onset septicaemia, shock
Circulatory overload (TACO)	Volume overload	Pulmonary oedema, hypertension

Management of suspected acute haemolytic reaction:

Stop the transfusion immediately
Maintain IV access, give IV fluids
Inform blood bank, return blood bag + fresh blood samples
Monitor urine output (renal failure risk)
Treat DIC if it develops

Delayed Reactions

Delayed haemolytic transfusion reaction (days to weeks): antibody response to minor blood group antigens; falling Hb, mild jaundice
Transfusion-associated graft vs. host disease (TA-GvHD): donor T-lymphocytes attack recipient tissues; prevented by irradiation of blood in immunocompromised patients
Post-transfusion purpura: rare; profound thrombocytopenia ~1 week post-transfusion
Iron overload: in repeatedly transfused patients (e.g. thalassaemia)

8. Complications of Blood Transfusion

Complications from a Single Transfusion

Haemolytic reactions (immune and non-immune)
Febrile and allergic reactions
Transmission of infection (now very rare with screening): HIV, hepatitis B/C, CMV, prions (vCJD)
TRALI
TACO (transfusion-associated circulatory overload)
Air embolism
Hypothermia (cold blood infused rapidly)

Complications of Massive Transfusion

Massive transfusion is defined as replacement of the patient's entire blood volume within 24 hours (roughly >10 units of blood).

Complication	Mechanism
Hypothermia	Cold stored blood; impairs coagulation and cardiac function
Hypocalcaemia	Citrate (anticoagulant in stored blood) chelates calcium; treat with IV calcium gluconate
Hyperkalaemia	K+ leaks from stored red cells; especially with old blood
Coagulopathy / Dilutional	Dilution of clotting factors and platelets; worsened by hypothermia and acidosis
Metabolic acidosis	Citric acid in stored blood; improved organ perfusion needed
Thrombocytopenia	Dilution; no platelets in stored blood
ARDS	Transfusion-related; micro-emboli and activated mediators
Citrate toxicity	Only significant at very high transfusion rates

9. Management of Coagulopathy

Managing coagulopathy during massive haemorrhage requires a damage control resuscitation approach:

FFP at high ratios (1:1 or 1:2 with pRBCs) - to replace clotting factors
Platelet concentrates - for thrombocytopenia or platelet dysfunction
Cryoprecipitate - low fibrinogen is very common; fibrinogen is vital to clot formation and stabilisation; guided by laboratory or point-of-care tests (e.g. thromboelastometry/ROTEM)
Tranexamic acid (TXA) - antifibrinolytic agent; most effective when given early (within 3 hours of injury)
Calcium gluconate - to counter citrate-mediated hypocalcaemia
Correct hypothermia and acidosis (the "lethal triad" with coagulopathy)

Clotting function should be assayed frequently during haemorrhage and acted upon until bleeding is controlled.

10. Massive Transfusion Protocol

Most surgical units now have a massive transfusion protocol (MTP) activated when massive blood loss is anticipated. Key features:

Pre-defined ratios of pRBCs : FFP : Platelets (often 1:1:1)
Early involvement of haematology and blood bank
Point-of-care coagulation monitoring (ROTEM/TEG)
Aggressive correction of hypothermia, acidosis, and hypocalcaemia
Use of TXA
Evidence from UK military (Role 3 facility) shows MTP improves trauma outcomes

11. Alternatives to Allogeneic Transfusion (Blood Conservation)

Autologous Blood Transfusion

Pre-operative autologous donation (PAD): patient donates own blood weeks before surgery
Intraoperative cell salvage (ICS): shed blood is collected, washed, and returned intraoperatively; common in cardiac, vascular, and orthopaedic surgery; contraindicated in malignancy and bowel contamination
Acute normovolaemic haemodilution (ANH): blood removed immediately pre-op, replaced with crystalloid/colloid, returned intraoperatively

Pharmacological Methods

Tranexamic acid: reduces surgical blood loss by antifibrinolysis
Desmopressin (DDAVP): increases Factor VIII and vWF release; used in mild haemophilia and platelet dysfunction
Erythropoietin (EPO): pre-operative stimulation of red cell production
Iron supplementation: optimise pre-operative haemoglobin

Blood Substitutes (Experimental)

An attractive alternative to the costly, immunogenic, and infection-risk transfusion process
Two categories:
- Biomimetic (haemoglobin-based oxygen carriers, HBOCs): mimic standard oxygen-carrying capacity; based on human, bovine, or recombinant technologies
- Abiotic (synthetic): primarily perfluorocarbon-based emulsions (second-generation showing potential in clinical trials)
One free haemoglobin solution is available in some countries where blood components are not readily available

12. Anaemia and Blood Transfusion in the Surgical Context

Pre-operative anaemia is common and associated with:

Increased perioperative morbidity and mortality
Higher likelihood of requiring transfusion
Prolonged hospital stay

Anaemia should be investigated and treated before elective surgery where possible:

Iron-deficiency anaemia: oral/IV iron ± EPO
Vitamin B12/folate deficiency: appropriate supplementation
The aim is to optimise Hb to reduce or avoid the need for allogeneic transfusion

Source: Bailey and Love's Short Practice of Surgery, 28th Edition - Chapter 2: Transfusion (pp. 42-46)

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