Does anyone here know if restricting short term (week or less) IV maintenance fluids will elevate serum sodium levels?  I know that your kidneys can drop your urine output to around 500mL/day and then you are looking at 700-900mL in normal insensible losses.  So even if I patient has a normal fluid loss calculated (Holliday-Segar) to be around 2800mL/day could you give something like 2000mL D5W 1/2NS 20meq k at 2000mL/day (since it is above the 1700mL/day would that would be lost with kidneys concentrating urine to max concentration) without impacting their fluid or electrolyte balance.  If at all, how long before you would see serum Na+ start to increase?  Patient is considered NPO.

This is form information purposes only... it isn't actually going to be used.

Thanks everyone

No.

Why?  Kidneys work hard to do their part and making it harder is asking for problems.

Total intake is the key.
If you also restrict or eliminate PO fluids, then yes, you might increase sodium levels somewhat.
You would also have a massive fluid deficit.
Remember that volume and dehydration are not the same; it is possible to have euvolemic dehydration, hypovolemic dehydration, or even hypervolemic dehydration

D5 1/2 c 20 isn't going to raise your na. Dextrose pushes out sodium. There are a lot if other factors to consider also. 3% will raise it faster but really should only be infused via central line because of osmolarity of it is in the 900s, 1000 is generally max for peripheral lines. 2%  is better tolerated peripheraly. .9 will raise it slowley if the reason it is low isnt pulling na faster than what .9 can raise it. 23% can be infused via slow bolus but is usually only used when intercranial pressure are life threatening, not to raise na all by itself.