1. a need for rescue treatment due to clinical deterioration defined by altered sensorium, convulsions, persistent vomiting, renal impairment, respiratory distress, a fall in Hb below 75g/dl, or in cases where initial haemoglobin was less than 9 g/dl a drop of 20% from the starting Hb if the initial Hb was less than 9g/dl, at any time during admission;