Undoubtedly some life can survive in space.
Would it be sentient? Probably not. I can't say for sure (as the universe is awfully big), but sentience is probably not a "goal" of evolution and is likely quite rare and associated with some strange evolutionary events. Simply put, there's no reason for things to get smarter. Bacteria probably have us beat.
Let's assume a minimum size needed for sentience (to house a brain, or something approximate - it may not be needed, but let's pretend that something as simple as a bacteria isn't sentient and can't be.). Let's also assume a minimum complexity.
Then let's take this big, complex thing and send it out into a freezing (nearly absolute zero), radiation filled vacuum. It seems...odd to me that it could survive unless, of course, there was some kind of protection (maybe a lead exoskeleton that could self pressurize?) and it was a creature that could hybernate in a way where it didn't need air/energy/could be chilled to absolute zero and be fine).
How long it will be out also matters. Like, if we're talking about "Ken was blown out the airlock and survived for 2 seconds"...well, humans may be able to manage that. If it's "Xylon was released into space, walled himself in a protective shell, and survived for a year", OK, I might buy that. But if it's "Argos was pushed out of the space ship and just hung out there for millenia floating", I'd have a harder time seeing this as accurate...(if nothing else, bits of Argos would start evaporating off, etc.)
Then again, if you don't go into the details and handwave, it could work. I've definitely seen the concept of "sentient gigantic species roaming space for eternities, eating the dust between the planets to survive, with mini-fusion reactors within them" whatever used in published works. The science is never gone into (and I think would be rather hard to find a way in which it could work), but hey! I can suspend disbelief!