Fluid Replacement Therapy (FTP) in Children: Diagnosis

00:01 So if we see a child with dehydration, it’s indicated to get a Chem-7, especially for severe dehydration because we’re concerned about imbalance of electrolytes.

00:15 And the electrolyte that gets children in trouble the most is actually sodium.

00:21 It is not necessary to get a Chem-7 for a child who has mild dehydration unless you have other concerns about the child.

00:29 Because those children, once their fluids have been replenished, will normalize their Chem-7.

00:35 So this is how a Chem-7 on your slide here is organized when we draw it out shorthand on a piece of paper.

00:42 Sodium, potassium, chloride, bicarb, BUN and creatinine, and glucose.

00:47 Let’s go through some examples.

00:50 Here are normal values for your Chem-7.

00:53 The sodium is 140, the potassium is around 3.8.

00:57 In this child, the chloride is normal at 110, and a normal bicarb is 24.

01:02 That 24 and that 140 are usually fairly carefully constricted at that normal value.

01:10 The next numbers, the 5 and 0.2, are the BUN and creatinine.

01:13 Those will herald signs of dehydration if the BUN is very high.

01:18 But the creatinine will remain normal unless the child is in renal failure or very severely dehydrated.

01:25 Glucose may be not so important in adults, but in children, it’s critical.

01:30 Because young children, when they get dehydrated, often get hypoglycemic.

01:35 This is because children’s liver stores of glycogen are much smaller than adults.

01:42 That means that without being fed for a period of time, they’re at much more risk for hypoglycemia and potentially even seizure from a prolonged period of dehydration.

01:54 So here’s what a mild dehydration may look like.

01:58 You can see our patient’s sodium, potassium, chloride and bicarb are all doing okay.

02:04 The BUN has started coming up a little bit and you can see the glucose has come down to 70, starting to drift down.

02:11 You might even see a slightly low bicarbonate, 19 or 20 wouldn’t be surprising.

02:17 But those are the key things that you’re going to see first.

02:20 Here’s a child with moderate dehydration.

02:23 The sodium is starting to creep up.

02:25 In this case, this child is just not drinking.

02:28 If the child were eating, say some liquid, but losing more liquid than she were drinking, that child might have a low sodium even in the face of dehydration.

02:40 You can see that now, the child’s bicarbonate is low.

02:45 It’s significantly acidotic all the way down to 13.

02:49 And the chloride is starting to creep up as a compensatory method.

02:54 But there’s something special about this that we have to note and it has to do with the sodium, the chloride and the bicarb.

03:01 Remember your equation for calculating a gap.

03:05 In this case, this child has large anion gap, which is a sign that this child is also having a metabolic acidosis.

03:14 I’m guessing this child either has ketones or this child has lactic acidosis, which might be driving that gap.

03:22 Again, the BUN is coming up and now the creatinine is coming up and look how low that glucose is getting.

03:27 Not surprising at all for a child with moderate dehydration.

03:31 So all these numbers are starting to become pretty significant and the anion gap is 20, 145 minus 112 minus 13.

03:42 In severe dehydration, now we’re really getting into trouble.

03:46 This child’s sodium is still high.

03:48 It might get much higher and we have to do some very fancy calculations to fix.

03:53 But of note, the chloride’s coming up.

03:56 The bicarb’s coming way down and the BUN and creatinine are significantly elevated.

04:00 Look how hypoglycemic this child is.

04:02 You can see how this will happen