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(angioedema) is strongly suggestive of anaphylaxis – an acute, life-threatening emergency. Other skin changes may include flushing and urticaria (‘nettle rash’ or hives) that also occur in less severe allergic reactions. Severe allergic and anaphylactic reactions may occur with all blood components but are most commonly reported with plasma-rich components such as platelets or FFP. In addition to the general resuscitation and supportive measures in Figure 5.1, specific points include: Staff in clinical areas carrying out blood transfusion must be trained in the emergency management of anaphylaxis, and epinephrine (adrenaline) must be available for emergency use. UK Resuscitation Council (UKRC) guidelines (2010 update) (http://www.resus.org.uk/pages/guide. htm) recommend the urgent administration of intramuscular (IM) epinephrine to treat anaphylaxis (adult dose 0.5 mL of 1:1000 (500 µg)). The IM route is rapidly effective (and life-saving) and prevents delay in attempting to obtain venous access in a shocked patient. It is not contraindicated in Transfusion Handbook / 5: Adverse effects of transfusion page 8 of 17 patients with coagulopathy or low platelet count. The 2012 BCSH guideline on the investigation and management of acute transfusion reactions recommends that intravenous epinephrine is only given by expert practitioners such as anaesthetists. Urgent expert medical care should be called immediately (e.g. critical care outreach team or local equivalent). After initial resuscitation, parenteral steroids or antihistamines may be given but these should not be the first-line therapy. After an anaphylactic reaction to blood, further investigation of the patient should be discussed with a clinical immunologist (including diagnosis of severe IgA deficiency – see below). Future transfusion policy should be discussed with a specialist in transfusion medicine. Most patients will have a single anaphylactic episode and essential transfusions should not be withheld (but must be carefully monitored). Those with recurrent episodes may benefit from using washed red cells or platelets in additive solution. There is little evidence to support the common practice of giving prophylactic antihistamines or steroids. Patients with recurrent reactions to FFP may be switched to pooled solvent detergent FFP, which rarely causes severe allergic reactions. 5.2.2.4: Severe allergic reactions associated with IgA deficiency Only a small minority of patients with IgA deficiency are at risk of developing severe allergic reactions to blood components. Those at most risk have severe IgA deficiency (70 but can occur at any age Implicated blood components Usually plasma or platelets Any Onset Up to 6 hours from transfusion (usually within 2 hours) Within 6 hours of transfusion Oxygen saturation Reduced Reduced Blood pressure Often low Often high Jugular venous pressure Normal or low Elevated Temperature Often raised Normal Chest X-ray Bilateral peri-hilar and nodular shadowing or ‘white out’, heart size normal Enlarged heart and characteristics of pulmonary oedema Echocardiogram Normal Abnormal Pulmonary artery wedge pressure Normal Elevated Blood count Fall in neutrophils and monocytes followed by neutrophil leucocytosis No specific changes Fluid challenge Improves Worsens Worsens Improves Transfusion Handbook / 5: Adverse effects of transfusion page 10 of 17 Response to diuretics Retrospective confirmation of TRALI requires the demonstration of antibodies in the donor’s plasma that react with antigens on the patient’s white blood cells. Suspected cases should be reported to the Blood Service and discussed with a transfusion medicine specialist who can advise on the need to investigate the implicated blood donors for antibodies to human leucocyte antigens (HLA) or human neutrophil antigens (HNA) with a view to removing them from the donor panel. SHOT data suggest an approximate incidence of TRALI of 1 in 150 000 units transfused. It is most common after transfusion of plasma-rich blood components such as FFP or platelets and implicated donors are usually females sensitised during previous pregnancy. Since the UK Blood Services switched to using male donors for producing FFP, resuspending pooled platelets in male plasma and screening female apheresis platelet donors for leucocyte antibodies, SHOT has documented a significant fall in both reported cases and mortality from TRALI. 5.2.2.6: Transfusion-associated circulatory overload (TACO) TACO is defined as acute or worsening pulmonary oedema within 6 hours of transfusion. Typical features include acute respiratory distress, tachycardia, raised blood pressure and evidence of positive fluid balance. It has probably been significantly under-reported in the past and may now be the most common cause of

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