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Dehydration Management: IV or PO?

I’m generally a “glass half full” person. Usually pretty optimistic about most things, which might be a bit unusual for a person whose specialty career (Pediatric Emergency Medicine) is focused on medical events when things go WRONG: whether due to luck, judgment, random misfortune, or some combination of all of these.

So I feel a little bit out of my sunny self when I write the following:  Now that we are out of high flu season, guess what?!?

We are into dehydration season!!

Out of the frying pan and into the fire.

Yep, cheerleader that I normally am, I’m breathing a heavy sigh and getting myself psychologically ready to manage many cases of fluid replacement. Whether due to stomach viruses or heat-related illness, this time of year there are always plenty of kids who are in some stage of evolution into their raisin form and the decision has to get made whether or not IV FLUIDS are necessary.

Thankfully, most of the time they aren’t. The overwhelming majority of kids, even those who could easily win a gold medal in Olympic level vomiting, can manage their rehydration and continued hydration by taking in fluids by mouth. Maybe it doesn’t surprise you, but many caregivers bring their children into emergency or urgent care absolutely convinced that their child needs an IV. Many caregivers are also surprised and some even disappointed if their clinician disagrees. So let’s dissect that thought process just a little and clear up some confusion about when IV fluids are necessary.

First of all, are IV fluids ever bad?

That seems like a reasonable place to start, right? There are a few situations where it’s important to be careful about robustly “filling the tank.”

  1. For patients with underlying heart conditions, adding a lot of fluid can overload the heart and cause failure. That can have many complications including respiratory distress and swelling of the extremities. Managing fluids must be done delicately in heart patients.
  2. Same thing with patients who have problems with their kidney function.  Too much fluid, especially if given too fast, can compromise that organ further and cause many downstream problems including acid-base and electrolyte imbalance.
  3. Kids with type 1 diabetes also are a special case when it comes to fluids as too much fluid too fast when they are in diabetic crisis can cause brain swelling. We are careful to avoid these situations.

Fortunately, children with these issues are in the minority, so let’s move on to otherwise healthy kids who are low on fluids for whatever reason. One consideration that clinicians have is the DEGREE of dehydration, which we can estimate based on clinical appearance.

Dehydration Evaluation

There are multiple body systems that factor into the dehydration evaluation. The heart rate goes up as fluid losses increase to ensure that enough blood volume (which carries oxygen to the tissues) gets circulated. The mental status and level of alertness are important features of this clinical picture as well — is the child interactive or listless? And does she make tears when she cries? I also look at and inside the mouth to see if the lips are dry and cracked or if there’s no saliva in the mouth and the mucus membranes are dry. That’s another indicator of fluid status.

Dehydration Treatment

Most children fall into the mild-moderate dehydration category, and most sources, including the American Academy of Pediatrics, recommend oral rehydration therapy.

Not IV fluids. There’s some good science that supports using the gastrointestinal (GI) system whenever possible for rehydration with IV fluids as a last resort. When I try for oral rehydration, I ask the child to suck on an ice cube or take VERY SMALL (5-10cc) sips of water or electrolyte replacement fluid every 15 minutes. If they can do this without vomiting, we are on the road to recovery and can maybe avoid the IV stick. 

When given in small amounts of fluid by mouth, especially electrolyte replacement fluid, and in some clinical settings an oral anti-nausea medicine (ondansetron is commonly used), oral rehydration is effective and saves the child a needle stick and risk of an IV infiltrate, which is when the fluid leaks out of the vein and into the surrounding soft tissue. This can be painful but is most often temporary and self-resolving. But still a complication.


For some children it the process of IV insertion is a difficult one, and it’s only fair to them that this is a part of the decision equation. Sometimes it becomes the critical factor whether we like it or not.  Dehydration makes veins “shrink down” and become more tricky to access. No one wants to poke a child with a needle any more times than is absolutely necessary, so a wise first step is to give the “college try” at small volume oral rehydration, at the very least to fill up the veins a little before an IV is attempted.

I’m always amazed at the number of children who are successful at oral rehydration even when they present for their medical evaluation looking as dry as a raisin, with the plan to try once with something by mouth before moving to an IV.

Other thoughts that go through my mind when I’m evaluating a child for dehydration are…

…of course, extent and length of symptoms, and input from the caregiver and/or the child him/herself. An exhausted child who has been up for 3 nights with vomiting and diarrhea may be less likely to be able to handle fluids, even from a syringe. And then there are just some children who are “refusers” and just will NOT participate in oral rehydration therapy. Whether they are too young to be reasoned with or have become so fearful of taking anything by mouth because it’s come up the last 18 times they tried, the acute care setting may not be the right time to take a hard line with a heavy hand.

The point of this entry today is to encourage anyone reading it to be open-minded when it comes to being convinced that bringing your child in “for IV fluids” is the only correct treatment plan. For many reasons, it might not be the best therapy. While there are indeed situations where IV fluids are definitely indicated- the moderate-severely dehydrated child (see definition above) who fails what we call a “PO trial” (attempt at fluids by mouth), or a dehydrated post-op tonsillectomy patient who has a lot of pain with swallowing, as a rule our first “go-to” therapy should be to try to rehydrate WITHOUT IV fluids, and if we can all start with that mindset, we may end up saving our kids a needlestick and ourselves some unmet expectations.

Glass half-full.

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About the Expert

headshot of Dr. Christina Johns

Dr. Christina Johns is a nationally recognized pediatric emergency physician and Senior Medical Advisor at PM Pediatric Care. An official spokesperson for the American Academy of Pediatrics, she is board-certified in both pediatrics and pediatric emergency medicine. With extensive media experience, the proud mom of two teenagers shares over 20 years of pediatric expertise with patients and families everywhere. Follow Dr. Johns for more insights on children’s health!