No Krausen

I pitched my yeast 4 days ago and for some reason there is no krausen. I followed the instructions on the recipe sheet and pitched at room temperature. My only guess as to why this is happening is because my yeast was accidentally left in the car for an afternoon after I bought it. Could that mean I killed the yeast due to it not being refrigerated?

It's an Irish Red Ale and I used White Labs Irish Ale Yeast WLP004. There is absolutely no airlock activity. I just took a hydrometer reading and it is at 1.044. I didn't use any foam-control and I sanitized all my equipment with Starsan. Unfortunately I forgot the actual temperature of the yeast when I pitched it.

First thing is first: No krausen and no bubbles mean nothing. It is entirely possible for a brew to reach high krausen and go back down before you notice, and lack of bubbles simply means that there are no bubbles.

That said, it does sound like you have either no fermentation or a very slow one (what was your OG?) 004 yeast does krausen quiet nicely (last time I used it, it blew the lid off the fermentor) so chances are you should have seen something. After 4 days, if your gravity is still within a few points of your OG, chances are you have a problem.

Don't stress though, it's no biggie. Just add more yeast (preferably, do a starter first, it will make sure the yeast you're adding is alive, and will shorten the lag time). The good news is that if you added dead yeast to the beer before, the new yeast will use it as nutrient, so you'll probably get good fermentation and little if any off flavors. 004 likes temps between 65 to 68F, so try to keep around the top of that range for the first 24 hours, and then go down to whatever temp you were planning to ferment at. This will help the yeast propagate faster at first.
Good luck!