The key tips: You will need several items in order to give your cat sub-Qs.See the Obtaining Supplies Cheaply section for information on where to buy fluids, needles and administration sets in the USA, UK and Canada. It may never be something you look forward to, but there are ways to make the process go more smoothly which not all vets are aware of, so they may not tell you about them. Vets can normally supply these items, and it is worth obtaining them from your vet the first time or two and being shown how to give sub-Qs by your vet or vet tech.If you follow these tips, you and your cat still may not necessarily enjoy the process (although some cats realise that sub-Qs make them feel better and actually remind their human if they are late giving them! Most people do eventually start sourcing their own supplies in order to save money.If your vet gives you another type of fluid, do check this is necessary because some other types can sting, plus some of them are more expensive than LRS.
The fluid most commonly used for CKD cats is Lactated Ringers Solution (LRS), but occasionally other fluid types are prescribed, usually because of other issues which need addressing.
(2016) Sparkes AH, Caney S, Chalhoub S, Elliott J, Finch N, Gajanayake I, Langston C, Lefebvre H, White J & Quimby J Journal of Feline Medicine & Surgery 18 pp219-239 state "although a balanced electrolyte solution such as lactated Ringer's solution is often used, a hypotonic solution (half-strength lactated Ringer's or 0.45% saline, with added potassium as needed) may be preferable to reduce the sodium load." These fluids contain dextrose, a form of sugar.
Therefore they do contain a few calories, though not enough to be of any real benefit (8.5 calories per 100ml of fluid).
It is fine to buy a few supplies from your vet to tide you over until you've read through this page and the Obtaining Supplies Cheaply page and sorted out your plans for which supplies to use and where to obtain them.
The first thing to do is to practice giving sub-Qs - on an orange. You can also practice on a piece of raw chicken with skin.
The feel of a needle going into an orange is similar to that of a needle going into a cat, so give it a go and see how it feels. Try to inject the needle between the skin and the muscle.