*and lose the respect of your coworkers at the same time!
First of all, this process is easier if you establish a reputation for yourself as a generally lazy and incompetent nurse. Like, if other nurses get anxious when you go near their patients, you'll know you're on the right track. It helps to be fairly argumentative and judgmental, and say inappropriate and obnoxious things as often as possible.
1. Ask your fellow ICU nurse to watch your two patients while you find an empty patient room to take a nap in. Ignore the fact that she has an unstable vented patient of her own, and ask her to wake you up in half an hour. Act really annoyed when she refuses to wake you up. Also, be sure to act like her suggestion to tell the charge nurse where you are going is a stupid one. Then, ask the PSR at the front desk to wake you up in half an hour.
2. When the charge nurse wakes you up in an hour, show your annoyance by not brushing your messy sleep hair and wrapping a blanket around your shoulders when you go back to check on your patients. Other nurses will notice and appreciate your commitment.
3. Get really mad at the PSR who didn't wake you up, even though the charge nurse told her not to because she wanted to do it herself. Try to make the PSR feel bad by telling her you'll never trust her again. She'll probably hide just how bad she feels about that but she's upset, really.
4. When your fellow ICU nurse makes a snide comment about how you should bring an alarm clock to work if you're going to sleep on the job and not be able to wake yourself up, act really upset because she sure isn't funny. Better yet, prove to her that you are the mature and seasoned professional by refusing to sit at the same ICU desk with her for the rest of the night. She'll get the message even more clearly if you get up every time she sits down next to you. In case she still hasn't noticed that you're upset, throw your pen around and sigh loudly.
5. Because you no longer like your fellow ICU nurse for telling the charge nurse that you abandoned your own ICU patients to take a nap, you no longer have to help her at all with her patient. This will reinforce to her that you are upset and hopefully she will learn her lesson. For example, if you hear her patient's pump alarming in the room, don't enter the room or attempt to see what's wrong, just announce to her how long it's been alarming for when you next see her. The patient will understand too, even in his drug-induced coma. Well, probably even more so because the pump is probably alarming to tell you his coma-inducing drugs are running out. Besides, to help your fellow ICU nurse would just ruin your carefully-established reputation as Lazy Nurse. Your fellow ICU nurse will miss the days when you would shout her name down the hallway when her pumps alarmed. So there.