This is likely a case of ABO incompatibility. It presents with hypotension and tachycardia The patient develops intravascular hemolysis leading to hemoglobinemia and hemoglobinuria and resultant acute renal failure. Anaesthetic drug hypersensitivity In anesthetized patients tachycardia,hypotension- usual presentation as most inhalational agents cause vasodilatation D I C Ruled out as it presents with bleeding from veni-puncture sites, GIT, lungs and skin and along with thrombosis of microcirculations and large vessels GVHD Ruled out as it presents with fever and maculopapular rash, diarrhea and LFT abnormalities.