Septic Transfusion Reaction

Bacterial contamination of a blood component can cause septic shock within minutes to hours of transfusion. Platelets carry the highest risk because they are stored at room temperature (20 to 24 degrees Celsius), which supports bacterial growth. Red cells carry a lower risk, with cold-growing organisms (for example Yersinia enterocolitica) as the classic cause. Mortality is high when recognition is delayed.

Sources. Donor bacteraemia (asymptomatic), skin flora at venepuncture, contaminated equipment and handling during processing, storage or at the bedside.

Clinical features.

• Fever of 39 degrees Celsius or over, or a rise of 2 degrees Celsius or more from baseline, with rigors.

• Hypotension, tachycardia, vomiting, diarrhoea, abdominal pain.

• Collapse, shock, disseminated intravascular coagulation, acute kidney injury and respiratory failure.

• Onset during or within 4 hours of transfusion (red cells often within minutes, platelets from minutes to many hours, particularly with slow growing Gram-positive organisms).

Classification. Confirmed when the same organism is cultured from the component and the patient. Probable or possible when the patient's blood or the component grows an organism, or when the clinical picture fits. A sepsis or severe febrile reaction without other cause should always be assumed to be bacterial contamination until cultures return.

Special groups. Immunosuppressed and neutropenic patients, neonates and patients with poor reserve are at greatest risk of death.

Differential diagnosis.

• Acute haemolytic reaction, including non-immune haemolysis.

• Febrile non-haemolytic reaction (diagnosis of exclusion, only after serious causes are excluded).

• Anaphylaxis and transfusion related acute lung injury.

• Sepsis from the patient's own infection (often the reason for transfusion).

• Hypotensive reaction.

Initial assessment. Airway, breathing, circulation, temperature, perfusion, lactate, urine output, bleeding and consciousness. Any rise in temperature of 2 degrees Celsius or more, rigors with hypotension, or collapse is enough to assume bacterial contamination until excluded while the work-up continues.

Immediate actions in order.

1. Stop the transfusion and clamp the line. Do not flush the line.

2. Assess the patient: airway, breathing, circulation, disability and exposure, give high flow oxygen, and call for senior and intensive care help.

3. Keep intravenous access with a new giving set and 0.9% sodium chloride.

4. Recheck identity of patient and unit.

5. Inform the blood bank and the responsible clinician at once, keep the unit, bag and set, and ask for all co-components from the same donation to be quarantined.

6. Do not restart and do not transfuse other components from the same donor.

Sepsis management within the first hour.

• Take blood cultures from the patient (two sets from different sites if possible), and send the component for Gram stain and culture, without delaying antibiotics.

• Give a broad spectrum antibiotic that covers Gram-negative and Gram-positive organisms, for example piperacillin with tazobactam 4.5 g intravenously in an adult (children: about 100 mg/kg of piperacillin), or meropenem 1 g intravenously, adjusted to local antibiotic policy. Add vancomycin 15 to 20 mg/kg intravenously when platelets are implicated and Gram-positive organisms are likely.

• Fluid resuscitation (30 mL/kg of 0.9% sodium chloride or balanced crystalloid in an adult with hypotension or raised lactate, reassessing), and noradrenaline if hypotension persists after fluids.

• Treat coagulopathy and organ failure, with intensive care as needed.

Investigations. Cultures of patient and product, Gram stain of the product, full blood count, coagulation, fibrinogen, urea, creatinine, lactate, liver function, repeat group and direct antiglobulin test (to exclude haemolysis), and chest imaging. The blood bank cultures the component and co-components, and tests the donor if the organism is identified.

Definitive management. Targeted antibiotics once the organism and sensitivities are known, source control, organ support and monitoring for complications of shock (renal failure, disseminated intravascular coagulation, acute respiratory distress syndrome).

Reporting. This is a serious reaction. Report immediately to the transfusion service and the blood supplier, so that other recipients of co-components can be identified and treated, and report to the haemovigilance system.

Further transfusion. Review the need, and use components from different donations once the investigation is complete.

Prevention.

• Careful donor selection and skin disinfection, diversion of the first volume of blood at collection, and rapid cold storage of red cells.

• Bacterial screening of platelets or pathogen reduction, and storage with agitation at 20 to 24 degrees Celsius for no more than the labelled shelf life.

• Visual inspection of every unit before use (discolouration, clots, swirling absent in platelets, leaks).

• Aseptic technique at the bedside, no prolonged time out of storage (start red cells within 30 minutes and finish within 4 hours), and no pooling or adding of fluids.

• Prompt reporting and quarantine to protect other recipients.