Ketones

Here is a question for doctors and nurses:

You have a patient (not a pregnant women) who is being sick, perhaps post-operatively or due to chemotherapy or an acute condition like appendicitis, viral meningitis or so on. You suspect they may be getting dehydrated and are deciding if you should give them IV fluids. What criteria would you use to assess for dehydration?

Answer: You would probably look at their skin to see if it was dry (does it stay up on the hand when pinched), is their mouth dry, is their urine output down and does their urine appear concentrated. They would be initial signs that would make you think perhaps IV fluids would be good if they are unable to rehydrate themselves orally, for example due to nausea and/or vomiting.

For patients who are starting to get dizzy, confused and drowsy, who aren’t producing tears if they’re crying and have symptoms such as a headache, increased pulse rate and/or low blood pressure you’d be likely to get those fluids up pretty pronto as they’ll likely feel better quickly and even if they could manage sips of fluids orally they’d struggle to rehydrate themselves sufficiently on sips of water.

Additionally, if you happened to dip the urine of someone, say with a Urinary Tract Infection (UTI) and noticed their urine was concentrated with increased specific gravity you would hopefully think “dehydration”.

In my time nursing on wards I never once came across a doctor or nurse use ketones as a test for dehydration or a criteria for prescribing IV fluid rehydration. With the sole exception of hyperemesis gravidarum.

That is because KETONES ARE NOT AN INDICATOR OF DEYDRATION and because nurses and doctors are more than capable of knowing if a patient is dehydrated from their clinical experience without dip tests. And because, with the exception of pregnant women, we generally believe a patient, for example a chemo patient, who says “I can’t stop throwing up and therefore am dehydrated because I’m not keeping fluid down”.

So why are ketones such a barrier to treatment for women with HG? Why do the vast majority of hospital guidelines for treating HG in the UK have “ketones in urine” (often it will specify 3+ or 4+) as a criteria for prescribing IV fluids?

Why do highly skilled doctors and nurses ignore all of their clinical judgment and experience and turn seriously dehydrated pregnant women away from hospital without IV fluids simply because she doesn’t have ketones in her urine? Often these women are showing every other clinical sign of dehydration such as dry skin, mouth and eyes, dramatically reduced urine output and concentrated dark urine, headache, lethargy, dizziness and even confusion. Yet that lack of ketones means she is denied fluid and sent home.

Is it because, ultimately, the doctors and nurses deep down believe that really she could correct the dehydration herself by simply drinking more and not throwing up? Is it because their commitment to following guidelines means that they are unable to trust their own clinical judgement? Is it because they ultimately believe that these women are just making a fuss?

And how do we change this situation?

Well I think really the only way to change it is to challenge it. If you are a doctor or nurse reading this then I implore you… find your hospital guidelines and request that they (ie. Those in charge) take out the line about ketonurina, replace it with “signs of dehydration” (simply that). Need an evidence base for that? Here you go… Click here for the systematic review which has shown that ketones are NOT an indicator of severity for hyperemesis gravidarum. Systematic Reviews are our highest level of evidence and what guidelines should be based on.

Furthermore, ketones shouldn’t be a barrier to discharge either, again because they are not an indicator of dehydration but also because a lot of pregnant women will simply have ketones throughout pregnancy! (for further information on that check out Prof Catherine Nelson-Piercy’s presentation from the ICHG conference this year).

What I would really love to see is a move towards trust by healthcare professionals, not just trust of the pregnant woman who is saying she can’t keep fluid down and therefore maintain her own hydration, but trust of one’s own ability to spot the signs of dehydration and know how to treat it, like you would for every other dehydration inducing condition. Even if a woman has early signs of dehydration sat there in A&E… if send her home she’ll be right back, because guess what… She’s puking up!! Rehydrate her while you wait for the antiemetic script to send her home and perhaps she’ll keep those oral meds down and manage to drink enough to not come back. That early bag or two of fluids could prevent days of admission next week, or even a termination of a wanted pregnancy.