Sir,Complications following blood transfusion during anaesthesia usually manifests as tachycardia, hypotension, and bronchospasm. We describe an unusual transfusion related complication in the form of diffuse bleeding, hypotension and brain bulge.A 12-year-old, 36kg girl presented with vomiting, headache and swaying while walking of 3 months duration. She had truncal ataxia and cerebellar signs. Magnetic Resonance Imaging study revealed right cerebellar lesion. She was scheduled for decompression of the lesion. Her investigations including coagulation profile were unremarkable. Monitoring during the procedure included electrocardiography, blood pressure (NIBP), end-tidal carbon dioxide (Etco2), pulse-oximetry (SpO2), temperature and urine output. Standard anaesthetic induction and maintenance was followed. Surgery was uneventful and haemostasis was achieved with a BP of 90/50 mmHg. Blood transfusion was started to replace the loss of about 800ml. There was drop of BP to 76/50mmHg during the transfusion. The transfusion rate was increased to maintain BP. However, this caused further decrease in BP. Simultaneously, the surgeon observed brain swelling and diffuse bleeding from the dural edges, muscle and skin. Transfusion reaction was suspected and hydrocortisone and crystalloids were administered. Blood sent for re-grouping and cross-matching did not reveal incompatibility. Haemostasis was possible only after administration of fresh frozen plasma. Following this, diffuse ooze stopped, brain swelling reduced and BP improved. Thirty minutes later, hematuria was observed, which cleared with frusemide. Post-extubation, coagulation status was normal. Rest of the hospital course was uneventful.Transfusion reactions under anaesthesia are observed even when compatibility exists. Various immune and non-immune mechanisms have been described for hemolytic transfusion reactions. Intra-operative brain bulge as a consequence of diffuse oozing subsequent to transfusion reaction has not been previously reported. We postulate that the vascular permeability changes noted in scenario such as transfusion related acute lung injury might occur in the cerebral microvasculature leading to capillary leakage and diffuse oozing. Though haemodilution can also lead to increased oozing, normal coagulation parameters excluded this cause. Recently, a French group observed 4.5% incidence of hypotensive transfusion reactions in a series involving 1159657 transfusions.1 This occurred mostly at the beginning of the transfusion, as in our case. Although this is more pronounced and reported with platelet transfusion, all blood products may be involved. Moore SB suggested the possible role of bradykinin in this reaction.2 We speculate that the hypotension, brain bulge and diffuse operative site bleeding could be a rare complication of blood transfusion. Recently, new mechanisms of red blood cell destruction have been postulated.3 These patients have little success with continued transfusions or steroids. Earlier, Eom et al have reported increased bleeding during scalp closure due to disseminated intravascular coagulation in a patient undergoing metastatic intracranial tumor resection.4 Kamatini and Sakai have reported occurrence of intraoperative haematuria following transfusion.5 We believe that the normal coagulation parameters, positive compatibility test and the temporal relationship between transfusion and occurrence of this complication, suggests the possibility of transfusion as the most probable cause. Our experience highlights the importance of early recognition of such unusual manifestation of transfusion reaction.