Help me understand Intravenous re-hydration?
August 7, 2015 2:41 PM Subscribe
What is in the re-hydration IV's at the end of ironman triathlons? What is in the rehydration IV they give post alcohol poisoning in the ER? Why does my book say it's better to eat/drink then to take IV?
From my book "where there is no doctor"
"In some areas, persons who are anemic or very weak spend their last penny to
have a liter of I.V. solution put into their veins. They believe that this will make them
stronger or their blood richer. But they are wrong! Intravenous solution is nothing
more than pure water with some salt or sugar in it. It gives less energy than a large
candy bar and makes the blood thinner, not richer. It does not help anemia or make
the weak person stronger.
Intravenous solution should be used only when a person can take nothing by
mouth, or when she is badly dehydrated (see p. 151).
If the sick person can swallow, give her a liter of water with sugar (or cereal)
and salt (see Rehydration Drink, p. 152). It will do as much for her as injecting
a liter of I.V. solution. For people who are able to eat, nutritious foods do more to
strengthen them than any type of I.V. fluid."
If that's true, why do they give IV to dehydrated people in the ER, and at the IRONMAN tent?
What's the best composition of ingredients in a rehydration IV?
Thanks!
From my book "where there is no doctor"
"In some areas, persons who are anemic or very weak spend their last penny to
have a liter of I.V. solution put into their veins. They believe that this will make them
stronger or their blood richer. But they are wrong! Intravenous solution is nothing
more than pure water with some salt or sugar in it. It gives less energy than a large
candy bar and makes the blood thinner, not richer. It does not help anemia or make
the weak person stronger.
Intravenous solution should be used only when a person can take nothing by
mouth, or when she is badly dehydrated (see p. 151).
If the sick person can swallow, give her a liter of water with sugar (or cereal)
and salt (see Rehydration Drink, p. 152). It will do as much for her as injecting
a liter of I.V. solution. For people who are able to eat, nutritious foods do more to
strengthen them than any type of I.V. fluid."
If that's true, why do they give IV to dehydrated people in the ER, and at the IRONMAN tent?
What's the best composition of ingredients in a rehydration IV?
Thanks!
In the ER a lot of the reason they will start an IV is to make administering medication easier.
posted by Requiax at 2:56 PM on August 7, 2015 [4 favorites]
posted by Requiax at 2:56 PM on August 7, 2015 [4 favorites]
It's dependent on the level of dehydration. The medical teams are actively searching the finishers line for people with severe dehydration That level of dehydration theoretically shouldn't happen with experienced competitors but it does happen. It's happened to me in a half IM. (And it sucked!)
Of course, many competitors will have some level of dehydration after an endurance event, but for most competitors oral rehydration is going to do the job just fine.
posted by 26.2 at 2:56 PM on August 7, 2015 [1 favorite]
Of course, many competitors will have some level of dehydration after an endurance event, but for most competitors oral rehydration is going to do the job just fine.
posted by 26.2 at 2:56 PM on August 7, 2015 [1 favorite]
IVs are used for rehydration in ERs and medical tents because liquids are not absorbed immediately from the GI tract into the bloodstream. One source I checked indicated a maximum rate of about 800 ml/27 fluid ounces per hour. If someone is severely dehydrated, he or she might have lost a lot more than that. An IV can the fluid into the bloodstream much more quickly.
posted by brianogilvie at 2:58 PM on August 7, 2015 [5 favorites]
posted by brianogilvie at 2:58 PM on August 7, 2015 [5 favorites]
In addition to what those above said, in the ER, the patient may be unconscious, or too incoherent to drink or eat, or they may be unable to keep anything down without vomiting. An IV may not be as good as eating or drinking, but it's better than nothing, which may be the only other option.
posted by une_heure_pleine at 3:01 PM on August 7, 2015 [3 favorites]
posted by une_heure_pleine at 3:01 PM on August 7, 2015 [3 favorites]
IANAD, but here's my understanding. People need a certain amount of water and electrolytes to fuel basic functioning. (This article includes some detail about the daily requirements for different components.) In normal circumstances, you get this combination through a combination of water and food. If you are using up an excessive amount of fluid and/or salts, you need to make up for the deficit. You're going through it at an increased rate (through extreme sweating, diarrhea, etc.) so you need to replace it more quickly. In some cases of dehydration, oral rehydration therapy is sufficient. This means drinking a solution of water with salts and sugars dissolved in it.
But the type of rehydration that is used depends upon the extent and the cause of the dehydration. In a more extreme case of dehydration, IV fluid allows for more rapid rehydration. And as EndsOfInvention states, this is a key tool if your body is not processing fluid well in some way (e.g. vomiting). In the ER, IV fluid allows for controlled, consistent rehydration. They can also add medication through the same IV if necessary. In the Ironman case, IV drips make sense for people who have lost extreme amounts of fluid and salts. Once you've reached a certain (dangerous) level of dehydration, the IV drip is the safest and fastest way to rehydrate because the fluid can enter your bloodstream more quickly than it can be absorbed.
The key mistake that the first paragraph you quoted points out is the assumption that IV fluid is providing some sort of special nutrients. It's meant to replace the fluid in your system with the same normal levels of salts and sugars. For anemic people, a saline solution obviously does nothing to address their iron deficiency. A standard IV drip addresses the problem of dehydration, but not other health issues.
posted by earth by april at 3:01 PM on August 7, 2015 [2 favorites]
But the type of rehydration that is used depends upon the extent and the cause of the dehydration. In a more extreme case of dehydration, IV fluid allows for more rapid rehydration. And as EndsOfInvention states, this is a key tool if your body is not processing fluid well in some way (e.g. vomiting). In the ER, IV fluid allows for controlled, consistent rehydration. They can also add medication through the same IV if necessary. In the Ironman case, IV drips make sense for people who have lost extreme amounts of fluid and salts. Once you've reached a certain (dangerous) level of dehydration, the IV drip is the safest and fastest way to rehydrate because the fluid can enter your bloodstream more quickly than it can be absorbed.
The key mistake that the first paragraph you quoted points out is the assumption that IV fluid is providing some sort of special nutrients. It's meant to replace the fluid in your system with the same normal levels of salts and sugars. For anemic people, a saline solution obviously does nothing to address their iron deficiency. A standard IV drip addresses the problem of dehydration, but not other health issues.
posted by earth by april at 3:01 PM on August 7, 2015 [2 favorites]
Response by poster: And what exactly is in the IV rehydration? Sugar, Salt water, but specifically, exactly, what? and how much?
posted by crawltopslow at 3:02 PM on August 7, 2015
posted by crawltopslow at 3:02 PM on August 7, 2015
And what exactly is in the IV rehydration? Sugar, Salt water, but specifically, exactly, what? and how much?
Saline
posted by phunniemee at 3:07 PM on August 7, 2015
Saline
posted by phunniemee at 3:07 PM on August 7, 2015
The basic is "normal saline:" 0.9 N NaCl (isotonic to blood). From there, you can do "D50" which is normal saline with 50% dextrose sugar (hence the name) or "ringers" or "lactated ringers" which has other electrolytes added (potassium and calcium with or without lactate).
posted by Missense Mutation at 3:09 PM on August 7, 2015
posted by Missense Mutation at 3:09 PM on August 7, 2015
Response by poster: I dont think it's just Saline, don't they also add sugar?
posted by crawltopslow at 3:10 PM on August 7, 2015
posted by crawltopslow at 3:10 PM on August 7, 2015
Varies. Normal saline is just sodium chloride. There are dextrose solutions, physiological solutions like Hartmann's which have all kinds in them, and colloids which are longer-chain starches. It depends on what you are trying to achieve with the infusion.
posted by tinkletown at 3:18 PM on August 7, 2015
posted by tinkletown at 3:18 PM on August 7, 2015
I have been IV rehydrated in the ER several times, and every time it because was I had been unable to keep food or liquids down for at least 12 hours (due to either stomach virus or hyperemesis gravardium), and could not physically rehydrate by swallowing because I couldn't keep anything in. The IV fluids were administered along with an anti-emetic so I would be able to take fluids by mouth.
One additional time my fetus had an elevated heartbeat and they determined I was dehydrated (though I had not been vomiting) and I got a liter by IV as well as them pushing fluids by mouth, because they wanted to rehydrate me as fast as possible and relieve the fetal distress.
Typically just saline -- you can get the glucose from your own body, even when you're dehydrated.
posted by Eyebrows McGee at 3:21 PM on August 7, 2015 [1 favorite]
One additional time my fetus had an elevated heartbeat and they determined I was dehydrated (though I had not been vomiting) and I got a liter by IV as well as them pushing fluids by mouth, because they wanted to rehydrate me as fast as possible and relieve the fetal distress.
Typically just saline -- you can get the glucose from your own body, even when you're dehydrated.
posted by Eyebrows McGee at 3:21 PM on August 7, 2015 [1 favorite]
Ringer's lactate has more than just saline in it, but is used in specific instances (e.g. on burn patients) beyond simple dehydration.
posted by rtha at 3:21 PM on August 7, 2015
posted by rtha at 3:21 PM on August 7, 2015
Response by poster: So what do they likely give the ironman competitors?
posted by crawltopslow at 3:32 PM on August 7, 2015
posted by crawltopslow at 3:32 PM on August 7, 2015
Probably just normal saline, since it is inexpensive (relative to other solutions, anyway) and the athletes are most likely to be suffering from simple dehydration rather than burns, blood loss, or renal failure.
posted by rtha at 3:41 PM on August 7, 2015
posted by rtha at 3:41 PM on August 7, 2015
The ironman folks likely get something like Ringer's lactate to give them a few electrolytes or just plain normal saline.
One thing I should point out is that your book specifically addresses rehydration in very resource-poor environments, where people may be making the choice between paying for IV fluids and food or other medication. In that case, if someone is able to swallow/eat, it's absolutely preferable for them to get oral rehydration and spend their limited money on food or medication. The same is true of people in resource-rich environments when there is no time constraint. It's why your PCP tells you to go home and have chicken soup when you have a stomach bug rather than giving you a liter of IV saline in the office. But actually IV saline is not very expensive as Western medications go and sometimes the time is more important than the route, and most Ironman competitors are not making a choice between IV fluid and food.
In a setting like the finish line of an Ironman, the medical staff is trying to rapidly triage and treat people in a specific environment where the likelihood of acute dehydration is high and their time is limited. IV saline is cheap as Western medicines go, so it makes sense for them to take someone who's looking bad, give them a liter of IV fluid, and then reassess whether the person is OK to go home or needs to go to a higher level of care (i.e., the ED) to make sure they don't have rhabdomyolysis or another exertion-related issue. That will take an hour or so as opposed to spending several hours monitoring them while they rehydrate slowly by the oral route, which will free up a spot in the medical tent and attention from the medical staff that can then be used for other distressed competitors.
posted by The Elusive Architeuthis at 3:55 PM on August 7, 2015 [10 favorites]
One thing I should point out is that your book specifically addresses rehydration in very resource-poor environments, where people may be making the choice between paying for IV fluids and food or other medication. In that case, if someone is able to swallow/eat, it's absolutely preferable for them to get oral rehydration and spend their limited money on food or medication. The same is true of people in resource-rich environments when there is no time constraint. It's why your PCP tells you to go home and have chicken soup when you have a stomach bug rather than giving you a liter of IV saline in the office. But actually IV saline is not very expensive as Western medications go and sometimes the time is more important than the route, and most Ironman competitors are not making a choice between IV fluid and food.
In a setting like the finish line of an Ironman, the medical staff is trying to rapidly triage and treat people in a specific environment where the likelihood of acute dehydration is high and their time is limited. IV saline is cheap as Western medicines go, so it makes sense for them to take someone who's looking bad, give them a liter of IV fluid, and then reassess whether the person is OK to go home or needs to go to a higher level of care (i.e., the ED) to make sure they don't have rhabdomyolysis or another exertion-related issue. That will take an hour or so as opposed to spending several hours monitoring them while they rehydrate slowly by the oral route, which will free up a spot in the medical tent and attention from the medical staff that can then be used for other distressed competitors.
posted by The Elusive Architeuthis at 3:55 PM on August 7, 2015 [10 favorites]
When you do intensive sports, your body diverts blood from the gut to the muscles. This might be part of why they do IV rehydration after the Ironman thing: Because there are situations under which your body will reject oral rehydration and this might be one of them. In other words, certain extreme states promoting vomiting even though you aren't "sick" (as in you don't have a stomach flu or similar). Having your body divert a lot of blood from your gut to your muscles for intensive physical workout might a situation where it is much quicker to do an IV than to wait for the body to accept oral rehydration.
Not a doctor. Just someone with serious health problems who reads a lot.
posted by Michele in California at 4:25 PM on August 7, 2015
Not a doctor. Just someone with serious health problems who reads a lot.
posted by Michele in California at 4:25 PM on August 7, 2015
IV glucose/dextrose is a poor rehydration solution as the sugars are metabolised and the infusion basically becomes free water, which can lead to critical dilution of blood salts. End consequences: cerebral impairment, coma and death.
If there is demonstrated hypoglycaemia this can be treated, but that is a completely separate issue to dehydration and blood volume loss.
IV saline all the way.
posted by chiquitita at 8:15 PM on August 7, 2015 [1 favorite]
If there is demonstrated hypoglycaemia this can be treated, but that is a completely separate issue to dehydration and blood volume loss.
IV saline all the way.
posted by chiquitita at 8:15 PM on August 7, 2015 [1 favorite]
another factor no one has mentioned about the ER is that if they know or suspect you have something more than dehydration going on and may require surgery, they'll put you on an IV because there's a fasting period required before surgery with general anesthetic to prevent the patient from vomiting while they're under.
posted by kagredon at 9:00 PM on August 7, 2015 [1 favorite]
posted by kagredon at 9:00 PM on August 7, 2015 [1 favorite]
Rehydrating solutions that have sugar in them have a very small amount. Dextrose 5%, at the most
D50 is a very concentated solution that is rarely used-mostly for patients with severe hypoglycemia-and only used for a short peried of time. It is terribly hard on the veins.
posted by SLC Mom at 9:21 PM on August 7, 2015
D50 is a very concentated solution that is rarely used-mostly for patients with severe hypoglycemia-and only used for a short peried of time. It is terribly hard on the veins.
posted by SLC Mom at 9:21 PM on August 7, 2015
> It is terribly hard on the veins.
Yeah, read the (horrifying, but not gross) excerpt in this recent fpp for details on why you wouldn't want to dump a bunch of sugar molecules directly into the bloodstream unless you really have to.
posted by rtha at 9:56 PM on August 7, 2015
Yeah, read the (horrifying, but not gross) excerpt in this recent fpp for details on why you wouldn't want to dump a bunch of sugar molecules directly into the bloodstream unless you really have to.
posted by rtha at 9:56 PM on August 7, 2015
I'm an ER doctor.
The fluids for dehydration are almost always just normal saline (no sugar in them unless your blood sugar is low and you can't eat for some reason).
We use IVs because it's faster, more efficient. If you have a great IV running, I can slam in a bolus of normal saline in 10-15 minutes. When's the last time you tried to drink a liter in 10 minutes?
That's really mostly all there is to it. Oral hydration works pretty much just as well, just like your book says, but ORS doesn't taste that great, because it's sugar-salt water, so it's hard to drink a large volume quickly.
Eating actual food with protein in it will maintain a normal blood sugar longer than pushing dextrose in an IV, and it can give you other electrolytes, vitamins, and minerals too - hence what "Where There Is No Doctor" says about getting stronger/healthier when you are sick. Also, people who live where there are no doctors are more likely to have malnutrition before they get sick and dehydrated, so they're already in a more vulnerable position than a healthy, first world country marathon runner who just needs to tank up after a tough day exercising - and likely to need more than just IV saline to get well.
posted by treehorn+bunny at 10:24 PM on August 7, 2015 [8 favorites]
The fluids for dehydration are almost always just normal saline (no sugar in them unless your blood sugar is low and you can't eat for some reason).
We use IVs because it's faster, more efficient. If you have a great IV running, I can slam in a bolus of normal saline in 10-15 minutes. When's the last time you tried to drink a liter in 10 minutes?
That's really mostly all there is to it. Oral hydration works pretty much just as well, just like your book says, but ORS doesn't taste that great, because it's sugar-salt water, so it's hard to drink a large volume quickly.
Eating actual food with protein in it will maintain a normal blood sugar longer than pushing dextrose in an IV, and it can give you other electrolytes, vitamins, and minerals too - hence what "Where There Is No Doctor" says about getting stronger/healthier when you are sick. Also, people who live where there are no doctors are more likely to have malnutrition before they get sick and dehydrated, so they're already in a more vulnerable position than a healthy, first world country marathon runner who just needs to tank up after a tough day exercising - and likely to need more than just IV saline to get well.
posted by treehorn+bunny at 10:24 PM on August 7, 2015 [8 favorites]
Also, I'm a little uncertain about what you mean by your second question, but there are some other things we often give IV to alcoholics (aside from just saline for hydration), such as the famous "banana bag". A banana bag has thiamine and multivitamin and folate in it, usually. It doesn't treat 'alcohol poisoning' per se, but it treats health problems caused by chronic alcohol abuse.
A person with 'alcohol poisoning' - let's say a 22 year old college student who just drank way too much one Saturday night, who isn't a chronic alcoholic - isn't necessarily very dehydrated, although alcohol is a diuretic, and they may have been vomiting, so they could be a little low on fluids. Mostly, anyone who's got an altered state of consciousness, be it from alcohol poisoning, heroin overdose, or severe head injury, often gets some amount of IV fluid since they are not alert enough to take food and drink by mouth. This is typically saline, as noted above.
posted by treehorn+bunny at 10:31 PM on August 7, 2015 [3 favorites]
A person with 'alcohol poisoning' - let's say a 22 year old college student who just drank way too much one Saturday night, who isn't a chronic alcoholic - isn't necessarily very dehydrated, although alcohol is a diuretic, and they may have been vomiting, so they could be a little low on fluids. Mostly, anyone who's got an altered state of consciousness, be it from alcohol poisoning, heroin overdose, or severe head injury, often gets some amount of IV fluid since they are not alert enough to take food and drink by mouth. This is typically saline, as noted above.
posted by treehorn+bunny at 10:31 PM on August 7, 2015 [3 favorites]
Why does my book say it's better to eat/drink then to take IV?
Every needle stick carries a risk. All else being equal, it's better to avoid it.
The risk is not high, so if there is any advantage to the IV, relative to eating/drinking, it makes sense to use the needle.
posted by Bruce H. at 9:45 AM on August 8, 2015 [1 favorite]
Every needle stick carries a risk. All else being equal, it's better to avoid it.
The risk is not high, so if there is any advantage to the IV, relative to eating/drinking, it makes sense to use the needle.
posted by Bruce H. at 9:45 AM on August 8, 2015 [1 favorite]
Your book specifies people who are "anemic or very weak" as people who won't be helped by IV fluids. "Anemic/weak" is different from "dehydrated." IV fluids are good at helping dehydration, but not very good at helping someone who needs calories or extra nutrients.
And where IV fluids are very expensive or difficult to get, even if someone's problem is dehydration, as long as they can drink fluids and keep them down, it'll be better for them to rehydrate orally because they won't have to spend as much money and time.
posted by snowmentality at 1:00 PM on August 8, 2015
And where IV fluids are very expensive or difficult to get, even if someone's problem is dehydration, as long as they can drink fluids and keep them down, it'll be better for them to rehydrate orally because they won't have to spend as much money and time.
posted by snowmentality at 1:00 PM on August 8, 2015
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posted by EndsOfInvention at 2:52 PM on August 7, 2015 [4 favorites]