HIE is an evolving process, which can be simplified into two insults. The initial insult is significant cerebral hypoxia and/or ischaemia which is followed by energy depletion, from anaerobic metabolism leading to the accumulation of lactate, and loss of cellular integrity. This sets in motion a cascade of events with the resultant formation of free radicals, proteases and caspases leading to cell damage and apoptosis, the secondary insult(3). The secondary energy failure has been shown to occur between 6-48 hours after the initial insult.