Amount and Frequency of Sub‑Q's

A list member wrote: "If you lift up their skin and it immediately springs back, they are not dehydrated substantially.  If it takes awhile to return to normal, then they are dehydrated."

The first statement is wrong, the result of reverse logic to which we sometimes fall victim. Clinical dehydration only becomes evident after about 5% of body weight has been lost in water. Thus if you lift up the skin and it *does not* immediately spring back the kitty is definitely dehydrated, but if the skin *does* spring back he may still have lost up to 4% of his weight in water! This would be about 145 ml for an 8-lb cat, definitely substantial and enough to need replacing!

Another test that's used is to check for slickness of gums, but this also only shows 5% dehydration. Any cat failing either of these tests needs immediate help, but passing them doesn't guarantee that a kitty isn't sub-clinically dehydrated!

The way most of us gauge the need for fluids is by knowing our cats. Compare how yours acts and feels before and after sub-q's. Chances are that when he needs a treatment his activity level will be low, he may have a sad, headachey look in his eyes. He might not show interest in food even though he hasn't been eating. He may just want to curl up and hide. Dehydration is described by human kidney patients as being like a bad hangover. After sub-q's a well-maintained crf kitty will often perk up, possibly get an appetite or want to explore or play. Or he may curl up purring to catch up on lost sleep. If you watch closely you'll learn the signs. Many cats will learn to tell you when it's time!

A good goal is to schedule sub-q amounts and times to beat the "hangover". If the effects of a given dose (say 100ml) don't seem to last the allotted time until the next scheduled treatment, I'll either give a bit more (perhaps 125ml) or give it sooner. Experiment with timing and doses until you find the combination that consistently seems to work best.

With Coco the progression was to increase the daily dose until it passed 150ml, which was the most I wanted to give her at once. At that point I switched to smaller doses twice daily, spaced roughly 12 hours apart. Since workday schedules sometimes don't allow equal spacing I'd adjust the split to roughly match the duration of time until the next treatment.

"Should a cat getting 150ml every two days switch to a daily dosage?"

There aren't any universal rules. Some people want to avoid giving large amounts at one time, others want to minimize the number of times they stick their kitties. Your preference is a decision between you and your cat.

That said, daily fluids ensure more consistent hydration. For a 5 lb cat (80 oz), 75 ml represents 3.3% of body weight. If two days after receiving 150 ml he shows no obvious signs of dehydration, it could be estimated that at the time of his last treatment he had at least a 102.6% hydration status. The day between this would have dropped to 99.3% (.7% dehydration, very slight) and as time passed this would gradually decline until he might reach 4% dehydration just before his next treatment (still undetectable, but significant) If switched to 75ml daily (starting one day after the last 150 ml dose), he'd never drop below his "off day" nearly-normal level and would have less "ups and downs".

Daily dosing also establishes a routine that many cats relate to better than "some days yes, some days not". Since they don't have pocket alarms they don't know if it's Monday, Tuesday or Friday, and some would rather know what to expect than to be wondering when it will be.