This post: http://dev-chieftain.livejournal.com/862710.html really got me thinking about the subject of 4th edition's Healing Surges. I was fortunate enough to run two games with Clerics in them, so I never truly had to answer this question. It's easy enough to say "The cleric uses your healing surges outside of battle to cast heal magic on you." I, more or less, hand-waved the entire concept of Second Winds to be an abstraction referring to Morale and Ignoring Pain(for a great example of this, check out the Batmaninatrix's fourth animated short.)
I'm currently running AD&D as I originally ran it when I was younger, a hodgepodge of 1st edition feel and 2nd edition clarity with the crunchier bits removed for ease of play. Yet, I enjoy the tactical combat boardgamey elements of 4th edition for their own sake, in much the same way that I enjoy Stratego and Dominion. Still, even if I decide to run the game for its tactical combat system, I couldn't bring myself to run a game calling itself Dungeons & Dragons without immersive roleplaying and stories that build off of the character's decisions and actions. In order to truly do this, I need to do two things first and foremost. One: Ditch the woefully short and simple equipment list in favor of something more elaborate(easy enough, I only need pull out any older edition's equipment list and give THAT to the players.) and Two: Determine what a healing surge means.
Something I greatly enjoyed about that blog post, was the suggestion that healing surges could be used to determine wounds, and that a second wind might represent some dirty field first aid. Similarly, the "spend as many healing surges as you want during a short rest" could represent more intensive first aid even. One thing's for certain, if I run another 4th edition game, players will not get all their healing surges back at the end of every day!