Dehydration question / early post op period

My husband has NOT had surgery yet, but we are working toward an early June surgery date.  He is self-employed and works outside 8-10 hours a day.  Not always a real physical job, but we live in the deep south and he it out in the heat of the day.  On a "normal" summer day he will drink 1-2 liters of water while he's out working. 

Problem #1:  He has heart trouble and has been retaining fluids.  His heart doctor has him on 80 mg of Lasix twice a day right now, and has limited his fluid intake to 32 oz a day. 

Problem #2:  Surgery in early June. 

He is concerned about getting dehydrated too easily this summer and wondering if he should put off his surgery until the fall.  What thoughts do you have on this?  We are really torn with knowing what we should do.  We will talk with the surgeon about it at our next appointment but that's not for a couple weeks.  Any advice or things to ask the doctor would be appreciated. 

I would want to discuss this with the surgeon and cardiologist in tandem. A conference call perhaps? I think that you've got a lot of very specific items that really only can be adequately (safely) answered by the surgeon. The one thing that jumps out at me, is when my FIL was retaining fluids, they actually wanted him to drink more to flush his system. There could be more to it than that--they are not very chatty about their medical issues, which is 100% their right, but perhaps I am missing a key element to the situation, too.  But I do recall him specifically saying that he was having to drink 'all damned day and night' and it was driving him crazy. 

Hope the surgeon and cardiologist are able to come up with a good plan for your husband!

Definitely sounds like a question for his doctors.  Is he supposed to limit his fluid intake like that even when he's working outdoors in warm weather?  That sounds dangerous.  Maybe that's not the best line of work for him if that is the case.

Thanks for your input - I called the surgeon today and talked with the nurse.  She is going to discuss his specifics with the surgeon and get it touch with the cardiologist's office as well and then get back to us.  Hopefully we will hear something back soon!