Transfusion in Anaesthesia
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Direct answer
Peri-operative transfusion is guided by haemoglobin triggers — 7 g/dL in most stable patients, around 8 g/dL where cardiac ischaemia compounds — rather than arbitrary volume loss, with products matched to what is lost: packed red cells for oxygen carriage, fresh frozen plasma and platelets for coagulopathy, cryoprecipitate for fibrinogen below about 150-200 mg/dL. Red cells store at 2-6°C for 35-42 days, platelets at 20-24°C with continuous agitation for five days, FFP at −30°C for about a year. Massive transfusion (over 10 units, one blood volume, or four units in an hour with ongoing bleeding) is managed with early balanced ratios approaching 1:1:1, plus calcium for citrate toxicity and warming against hypothermia. Suspected reactions — haemolytic, TRALI, TACO, febrile non-haemolytic — all begin with the same response: stop the unit and re-run the bedside identity check.
What you must remember
- Triggers: Hb 7 g/dL in most stable patients, about 8 g/dL in cardiac disease and critical-organ ischaemia; transfuse one unit, then reassess rather than ordering two reflexively.
- Storage rules: red cells 2-6°C, 35 days in CPDA-1 or 42 days in additive solution; platelets 20-24°C with agitation, five days; FFP at −30°C for about a year, thawed and used within 24 hours.
- Massive transfusion definitions: over 10 units in 24 hours, replacement of one blood volume, or four units in one hour with ongoing haemorrhage; protocol-driven early plasma and platelets in near-balanced ratios.
- Citrate and calcium: rapid transfusion binds ionised calcium, causing hypotension and QT prolongation — calcium chloride or gluconate replaces it during rapid infusion; hypothermia and hypocalcaemia are the two under-feared complications of fast transfusion.
- Reaction fingerprints: acute haemolytic — fever, hypotension, haemoglobinuria early in the unit (ABO clerical error); TRALI — hypoxaemia with bilateral infiltrates within 6 hours; TACO — hypertension and pulmonary oedema in fluid-intolerant patients; febrile non-haemolytic — the commonest, benign; anaphylaxis in IgA deficiency — washed cells thereafter.
- Bedside safety ritual: two-person identity check of the unit and patient against the crossmatch report, visual inspection for discolouration, clots or haemolysis, and a filter and blood-giving set for every unit; O negative is the emergency unknown-group choice (O positive acceptable for men and postmenopausal women in shortage).
- Indian practice framing: blood banking operates under the Drugs and Cosmetics Rules with National Blood Transfusion Council guidance; consent, prescription by a registered medical practitioner and crossmatch documentation are legal requirements the theatre team must see honoured.
Managing a massive transfusion, minute by minute
A ruptured ectopic pregnancy arrives in theatre with a systolic of 70 and free fluid filling the abdomen: the massive haemorrhage protocol activates at the first word. While the surgeon clamps, two large-bore cannulae and a rapid infuser with a blood warmer run; four units of O negative arrive before the crossmatch. The sequence of thought is fixed: perfusion now (blood, not crystalloid), then components — after roughly one blood volume, plasma and platelets in near-equal ratios, guided by point-of-care testing where available — then chemistry: ionised calcium replaced as the pressure softens with each rapid unit, and the temperature held only by active warming.
The recognition drills run in parallel. Fever with hypotension in the first minutes of a unit means stop the transfusion, re-run the identity check with a second person, and send the unit and fresh samples back to the bank — presumptive haemolysis until excluded. Breathlessness with hypertension and crackles two units into an elderly patient's transfusion is TACO: slow, diurese, and think before the next unit. And the audit trail — units, times, lot numbers, vitals — is the technician's record-keeping contribution.
How the exam frames it
Questions are thresholds, temperatures and classifications. The 7 g/dL trigger with its 8 g/dL cardiac exception is standard; storage temperatures and shelf lives are asked as a block (2-6°C for red cells, 20-24°C with agitation for platelets, −30°C for FFP), and candidates lose marks by forgetting the agitation. Reactions are tested as vignettes: the TRALI-TACO discrimination (hypoxaemia with hypotension versus hypertension with fluid overload, both within six hours) is the modern favourite. The Indian context earns marks when candidates frame the regulatory skeleton — Drugs and Cosmetics Rules and NBTC standards, the requirement of a registered medical practitioner's prescription, and the blood bank's licensed role — because theatre staff are the enforcement point for consent, identification and documentation.
Frequently asked questions
What haemoglobin level triggers peri-operative transfusion?
Seven grams per decilitre in most stable patients, with a threshold around 8 g/dL in cardiac disease, older age and critical-organ ischaemia; transfuse single units and reassess rather than ordering multiples reflexively.
How are blood products stored?
Red cells at 2-6°C for 35-42 days depending on anticoagulant or additive solution, platelets at 20-24°C with continuous agitation for five days, and FFP and cryoprecipitate frozen at −30°C for about a year.
What defines massive transfusion?
Commonly more than 10 units in 24 hours, replacement of one blood volume, or four units within an hour with ongoing bleeding — triggering protocol-driven plasma and platelets in near-balanced ratios with red cells.
How do TRALI and TACO differ?
TRALI is immune-mediated non-cardiogenic pulmonary oedema within six hours — hypoxaemia with bilateral infiltrates, often with fever and hypotension, treated supportively; TACO is circulatory overload with hypertension in susceptible patients, treated by stopping, slowing and diuresis.
What is the immediate response to a suspected transfusion reaction?
Stop the transfusion immediately, maintain venous access with normal saline, perform a two-person recheck of the unit against the patient's identity, monitor vitals, and return the unit with fresh blood samples to the blood bank for investigation.