Transfusion triggers

SummaryTransfusion triggers are increasingly accepted in surgery and in the critically ill. There is very little evidence to suggest a restrictive policy is harmful although higher levels might be sensible in those with cardiovascular disease. A considerable tranche of literature shows that blood is bad for a patient but to date no clear mechanism has emerged and there is an argument that needing blood, a surrogate for illness may be as relevant. The impact of anaemia in the postoperative phase has not been evaluated adequately. The triggers lend themselves to non-acute elective situations but where there is acute blood loss and haemodynamic instability a slightly higher threshold, nearer 10 g/dl, allows a margin of safety.