I read on article about some campers who got stranded somewhere and ran out of water. After a few days they were rescued and the writer said that he could feel life flowing back into his limbs as he drank water.
So what actually happens? Your body is nearly shut down and your stomach gets filled with water. How quickly does it get in the blood? Does it refresh everything at once or does your body have a system to restart.
A very complex topic. Dehydration is defined as a reduction in total body water below the normal level without a proportional reduction in sodium, bicarb, and potassium, resulting in a critical rise in the plasma sodium and other electrolyte concentrations. Since you’re positing a situation of dehydration from absolute water deprivation (as opposed to severe diarrhea), then 2/3 of water lost would come from within the cells, with the remaining third lost from extra-cellular fluid, including fluid in the circulatory system. So you don’t see falling blood pressure or increased pulse rate from volume loss unless the dehydration is severe. But you do get signs and symptoms of elevated sodium, which can be quite fatal. High sodium levels begin to impair nerve function, brain function, and so on.
Severe dehydration (with its accompanying signs of delirium/unconsciousness, inability to swallow or hold down fluids, uncontrolled fevers, spasming/cramping muscles) needs treatment with IV fluids emergently, and those fluids should be as close in electrolytes to normal human fluid plasma as possible. Normal saline with some glucose and potassium added, or lactated ringer’s suffices.
Less severe dehydration can generally be managed with oral fluid replacement, but it should contain electrolytes and glucose in it, not just plain water. It needs to be given slowly, in sips, to allow for absorption to occur and not overfill the stomach, which can cause vomiting and subsequent aspiration, which is not nice. Gatorade is not a bad oral rehydration solution, nor is pedialyte. The resulting osmolarity of the solution should be around 200 to 325 milliosmoles/liter. The carbohydrate (sugar) component is especially important, as that helps promote intestinal absorption of the fluid. Inadequate carbs and osmolality can induce diarrhea, while excess of those substances can pull more fluids OUT of the body rather than replace.
One can make their own oral rehydration solution by adding 2 Tbsp of sugar and 1/2 tsp of salt to a quart of water.
Once fluids and electrolytes start getting absorbed, things generally start improving fairly rapidly, assuming no permanent damage has already been done. But the aftereffects of severe dehydration may still be felt for days to weeks.
Hope that helps. The above is a very extreme simplification of what goes on during fluid deprivation dehydration.
I don’t have anything to add to @Qadgop_the_Mercotan description and treatment options other than dehydration is an extremely common ailment in backcountry medicine, and can progress rapidly to a life threatening condition in both hot and cold environments and especially at altitude. People are often not conscious of how much fluid loss is occurring in cold weather due to exertion, and in below freezing conditions it can be be difficult to keep water in a liquid state, especially with bladders where the water in the tube will freeze up. It is more obvious that people should drink in hot weather but I’ve had multiple WFR/R instructors who worked as park rangers in Grand Canyon, Death Valley, and various Southwest parks who said that rescuing people who walked down into the canyon or out in the desert with just a small bottle of water and their phone was a daily occurrence regardless of signage.
As notee, moderate dehydration can be treated by allowing the patient to sip (not drink continuously) water with oral rehydration therapy (electrolyte salts and dextrose or sucrose), preferably in shade if it is a hot environment. You can certainly mix your own as @Qadgop_the_Mercotan suggested but I carry packets of medical oral replacement salts in medkits because they are sterile, shelf-stable, and come with specific dosing instructions for children and adults. Be aware that once these solutions are mixed they become a great medium for bacterial and fungal growth, so you don’t want to leave them sitting around unrefrigerated for more than a day or put them in a bladder or other difficult-to-clean storage system. I carry a 1 liter bottle that is specifically for rehydration and camp use even though I typically carry water in various types of bladders.
Oral rehydration is suitable for someone who became moderately dehydrated through exertion or just not drinking enough, but for someone who is becoming dehydrated through another malady (food poisoning, infectious disease, et cetera), or is exhibiting signs of severe dehydration, immediate evac is required, as such a condition can result in other medical issues that cannot be treated with backcountry resources and can result in brain damage, cardiac problems, et cetera. Since the patient will probably not be capable of walking any distance it is definitely a situation where you would consider calling in for medivac if you are not within a few miles of a trailhead.
Having suffered moderate dehydration on a couple of occasions I can offer the anecdota that you do indeed feel a quick burst of energy, and in particular stop the uncontrollable shaking that often accompanies moderate dehydration, but you still feel weak for up to several days while your muscles replenish glycogen stores and return to electrolyte balance. I’ve never had gastrointestinal distress but that does occur in some people (especially if you overdue the salts). I now make a point of carrying water on even the shortest excursions, and more water than I expect to need on longer ones, along with multiple ways to filter and treat drinking water, as well as electrolyte tablets in addition to the oral rehydration salts in the medkit.
Stranger
I do a few sports (backcountry skiing, dirtbiking, MTB) where it’s pretty darn easy to get dehydrated. It’s really hard to resist the urge to glug water when you get to it at the truck, and it’s really uncomfortable to feel the bolus of water just sitting in your stomach not being absorbed. I try to use Cytomax or similar, but a 3L bladder on a 6 hour ride or a big tour doesn’t do it. And then there’s water toxicity… Electrolytes are weird.
@Qadgop, you forgot about the baking soda in oral rehydration solution, but otherwise, you’re correct.
2T sugar (this could include honey or molasses in a pinch), 1/2 t salt, and 1/2 t baking soda in 1 liter or quart of water.
Some years back, my sister had terrible diarrhea caused by taking the wrong antibiotic, and was so weak, she went to the ER. She couldn’t believe how much better she felt after getting a liter of fluid.
I did not forget that. It is not currently recommended by the experts unless there is significant acidosis. Though I’m sure a lot of folks are still including it in their basic recipes.
Bicarbonate (baking soda) was often added to oral rehydration solutions (ORS) for patients with diarrhea because it was speculated that bicarb ions were more efficiently absorbed by the small bowel. But studies have subsequently shown that bicarbonate-containing ORS does not have any clinically significant effect on the absorption efficiency of ORS, either beneficial or adverse, and its use is relevant only for correction of metabolic acidosis of diarrheal dehydration.
Of course, adding bicarb won’t hurt either.
Hi Qadgop, thanks for the great explanation. My question is about the speed of the IV. I’ve had IVs done before (for non-dehydration reasons) and the drip was extremely slow. Is it really fast enough to save someone’s life if they’re dehydrated to the point of near-death? (unless the IV can be set to a fast enough drip pace that I didn’t experience or see myself)
I once had a gastric bug and didn’t eat or drink anything for four days. I felt okay, but on the fourth day it dawned on me that not drinking wasn’t a good thing. I had a phone appt with the doctor was as told to go immediately to emergency. The said I was extremely dehydrated and gave me 3-4 pints of saline by IV during the 3-4 hours I was there. When I looked at the back of my hand, I could see it had noticeably puffed up.
I wasn’t given any medicine, but the next day I broke out in puss filled pimples all over my face. I called the doctor again and got an antibiotic in a day or so.
Sure, if it’s critical the IV is set to flow faster. Pressure devices can be used to speed up infusion even more, at need. This of course carries risks of fluid overload, so needs to be monitored closely.
I’ve seen it running at 1000ml/hour in extreme cases, usually for the first bag only. This is mainly used for people with profound dehydration from malnutrition (most common in senior citizens) or pregnant women with hyperemesis gravidarum. The HG bags were also often fortified with an antiemetic, usually Phenergan (which isn’t recommended to be given IV any more) and multivitamins.
For people, usually small children, who weighed less than 50kg, the rate would be adjusted to 20ml/kg/hour to keep from fluid-overloading them.
In the past, if a person’s veins were so collapsed, access was difficult or impossible, IV fluid could be injected into a fat pad, like the abdomen, breasts, or buttocks, and could be absorbed from there. I never saw an IO access port ordered, but apparently it’s not uncommonly used in pediatrics, especially in babies whose bones are much softer and have larger marrow chambers. And yes, it sounds like it is EXTREMELY painful.
I fasted during Ramadan for 18 years.
In the summer that meant not drinking anything between 3am and 11pm. It was of course the hottest time of the year and I was still going to work.
The very first thing I drank when breaking the fast was a small glass of milk, followed a few minutes later by a small glass of a Gatorade-like beverage. It was probably psychological but I swore I could feel a change running through my body, up to my fingertips. It felt as if every cell was sort of waking up.
In college I was a normal control in a number of studies. I would look through all the offerings and “volunteer” for the ones that paid the most for the least discomfort.
One study paid very well because it involved two days hospitalization with an IV. It was looking at dehydration and levels of ADH in the serum.
I was given concentrated saline IV, causing predictable dehydration. I had to rate how dehydrated I was 1-5, and it was amazing just how dehydrated they made me! I reached a “5”, then was even more dehydrated. It was awful.
Then I had to swish ice chips in my mouth, spitting out the water. It was so hard not to swallow, but they were constantly evaluating the osmolality of my serum so they could tell if I swallowed. The study demonstrated the presence of osmoteceptors in the mouth. Serum ADH levels changed when I swished the ice chips even though I did not swallow.
Cats who don’t drink enough are sometimes given subcutaneous injections of normal saline. The cats don’t seem to mind, so i doubt it’s painful. A friend claimed that doctors sometimes treat dehydration with an enema in places where it’s hard to get a sterile IV. I’m curious if that would work.
But yeah, home/field treatment for dehydration is to sip Gatorade or Pedialyte. You want to use the Gatorade with sugar, not the sugar-free stuff, as the sugar helps the gut absorb water.
I’ll dispute this definition. It’s the significant loss of free water full stop. One can have dehydration with proportion loss of sodium (isotonic dehydration) and we frequently see cases of dehydration presenting with low sodium (hyponatremic dehydration), more frequently than high sodium levels, in kids anyway.
A huge immunization success has been the impact of Rotavirus vaccines: a practice my size, several docs, had a dozen or so admissions for diarrhea with dehydration per year before that vaccine; within a year or so of its release it dropped to one or less.
Liberal use of anti- emetics (Zofran) also have had big impact.
To me though the following claim is of note:
Really?
Mostly severely dehydrated individuals are nauseated and drinking large amounts risks upchucking! But could there have been some immediate perceived response to the brain from the sensory input? Or was that statement just storytelling?
More than that. Dehydration also means a period of no carb intake. The body breaks down fats and muscle for energy instead which produces ketones. Those ketones are what make those dehydrated nauseated and unable to take fluids in orally. Getting glucose in to offset that is key.
Some random data points from the ER.
I’ve placed manual intra osseous lines in children before, now that we have power tools, ERs and prehospital EMS commonly do them on adults. With the delayed transport of a backcountry rescue, they would be a great option for hypovolemic shock. People mostly don’t complain that they’re much worse than a large bore IV.
3 liters over an hour by IV is not a particularly big deal.
I’m skeptical that drinking water would be directly perceived as flowing into the limbs, I think DSeid is right about that.
Pediatric fluid bolus is 20ml/kg over about 10 min, you might repeat that 2-3x.
I ended up hospitalized from intractible diarrhea, and was on 2 bags full flow 24/7 and it was a week before they felt comfortable sending me home, and I have an EMS trained hubby =)
[and no immodium and lomotil were useless. When one has cancer and has been chemcially assaulted for 28 weeks, and then gets nuked heavily for 21 days, there is no lining to the digestive system. Think about it, a 36 foot road rash, that will not clot because it is inside where it is wet and moving around. I was not only crapping out whatever i ate or drank, I was crapping out my interstitial fluid as well. Immodium and lomotil work by slowing down peristalsis, and my gut movement was fine, it was the lack of lining to absorb the water out of my wastestream. Now if freaking kaopectate was actually still kaolin and pectin, it would have worked by gelling the contents of my poop, which would have slowed things down. People with my issue - having parts of my guts removed and rerouted to pooping through a stoma on the side of my stomach, use marshmallows and gelatin to thicken their chyme to slow things down. ]
I am autistic and perceive things differently than those who are not neurospicy, and I can take a drink of water and it feels like it is going down and spreading around. I realize most all of stuff like this can be referred sensation [hells bells, when i had stomach surgery once, I sat up afterwards and the referred pain of someone trying to peel off my shoulderblades with a dull butterknife was horrible!] but I could see a percieved feeling like life was flowing back into my extremities. I mean, if a drink of common water can feel like it is spreading around my ribcage and abdomen when I am not dehydrated, why can’t someone feel like they are being affected?