I did dialysis nursing for about a year and half and in my younger days as a nurse. It is difficult in that the populace of patients never feel good, ever. They are chronically tired, drained, achy, whiny, noncompliant, etc but to that I will add that if I had to be a dialysis patient, I would be the same. They are mostly diabetic/blood pressures out of control for so many years that they've shut down their kidneys on their own, so to speak. There are some who were victims of other causes of renal failure, though, so bear in mind I'm not slamming dialysis pts. In fact, I myself have those precursing factors not being treated very aggressively at the moment due to no insurance so I may yet end up in renal failure myself some day! I would choose, no. I'd rather not, thank you very much.
It is very hard on your joints. Especially your back. LOTS of backbreaking bending over the pts. arm or shoulder area, depending on if they have a temporary cath in place while shunt or fistula is maturing. It takes a certain finesse and lots practice but it is doable in so far as the cannulation. Some of the shunts being worn out after every other day usage. They crash on you a lot, too. B/P just plummets and they must be revived/resuscitated. There's a lot of teaching potential, encouragement to improve their diet if they're willing to learn, to be able to better live with renal failure.
I learned valuable nursing skills, so it is definitely something to consider when weighing the two offers you've had.
If your back can take the constant bending over and holding that position for 3-5 minutes without pulling you into a constant pretzel, then go for it. Also, if you shadow at the dialysis clinic, ask them to let you observe all or most of the day. There is a thing in dialysis called "switchover" that occurs around 10:30 to 11:00 a.m. in which they take off of machines, switch over to the next group of dialysis pts. The company I worked with wouldn't let me observe this when I shadowed with them. It was too chaotic to the observer, they said, and didn't want it to scare me off!
Just a thought.
I've also done gastro in a clinic. Much kinder to your physical body, in my opinion. And just as interesting. IV skills, assessment, intervention, are used constantly. Might be a better option if your body is as aging from overuse in general as mine is.