Asking for raise in small cath lab.

I currently work in a small cath lab. One room lab with 3 nurses and 3 xray techs. One nurse just had her last day and her position has not been filled and according to my boss nobody has even interviewed for it in the 1.5 months its been posted. Because of this my on call time has increased greatly. While small we are also a pretty busy lab and probably could actually use 4 RNs. I know they also don't want to hire a new grad.

One of the xray techs is also leaving to move to a hospital closer to her house, they have known she is leaving for 2 months but have been having trouble filling her position. During her last week they offered her a raise to stay.

I am a new grad who has been working in this cath lab for past 7-8 months (same amount of time as the xray tech offered the raise). During this time I have become the main doctor's go to person to having the day run smooth (this has been told to me by 2 other employees).

I could go on and on about all the problems of the department but will spare that. I think I deserve a raise and I know if I find another job they will be hurting badly.

Do I stand a chance even asking? I don't want to sound threatening but I know they will have trouble filling the position. The other nurse has also informed me that if I leave she is leaving (she said she would go work registry while she finishes school). I also understand that I'm not going to get bumped 7 dollars to typical cath lab nurse pay but I just need something to make it worth my while.

Any suggestions? Thoughts? Ways to go about it?
If you want a raise, ask for it. Give them you're reasoning. If they are reasonable, they will show you respect as you show them respect.

Personally, I would not put any type of threat (as mentioned in your post) into your request. Just because your departure would be a hardship for them, I don't think it is professional or wise to phrase a request for a raise in those terms.

Quote from graft...I think I deserve a raise and I know if I find another job they will be hurting badly. Any suggestions? Thoughts? Ways to go about it?

Sit down a make a list of things that you specifically do that makes you invaluable: how have you saved them $$, how have you improved time management, etc. Then make an appt with your manager. Discuss all of this and simply ask for a raise. I wouldn't threaten anything or you may find yourself the next one out the door.