D5W is a preparation of IV solution that has 5% dextrose in pure water (so no salt, unlike normal saline which contains salt). It is mainly used to maintain a patient's blood sugar if they are not able to eat for some reason, as would be the case before a surgery, or if you were worried about them becoming hypoglycemic.
It will cause blood clots.
there are 170 calories in 1L D5W
No, causes crystallization