De-Hydration and Heat Stroke

[hoot72]

Hi

Any words of wisdom from experinced medics in dealing with heat stroke and de-hydration in a tropical jungle environment with high humidity levels in the upper 90;s and ground temperature's in access of 34+ celcius?

Has anyone resorted to using IV and salt-rehydration tablets?

[SouthernDZ]

It’s a problem and is one reason SFAS doesn’t run during the height of summer.

The best fluid to drink when you are sweating is water. I haven’t seen salt tablets used since the 80s; taking salt tablets may raise the body's sodium level to hazardous levels. Although there is some salt in perspiration, you don't really lose that much with your sweat, except in special (usually pathological) circumstances. As prevention is always the best method, have your guys eat their salt, sugar and cocoa packet with every meal and wash down with a quart of water (cocoa has potassium). Putting any kind of sport drink in the canteen or camelback is a bad idea. Things will grow in the sugar residue, especially in the jungle. Nalgene bottles work pretty well; have them flip a couple of spoonfuls in their mouths occasionally. Gatorade is the most reasonable price; make certain to cut it first. Remember, significant hyponatremia can result from voluntary overhydration and can be dangerous.

As for heat stroke, just remember that hyponatremia and significant dehydration are not always associated. Heat stroke usually results from total hypothalamic failure; the body can’t regulate, the temperature rises rapidly, the sweating system fails and the body cannot cool down. Cool them down, but go easy on the fluids with these casualties.

It’s a jungle out there.

[sfbaby1982]

Hey what are your thoughts on the oral re hydration salts that they so freely issued during the Q? I don't think that they are the salt tablets that you mentioned and if I remember correctly they are pasted on Potassium salt.

R

[hoot72]

Originally Posted by SouthernDZ

It’s a problem and is one reason SFAS doesn’t run during the height of summer.

The best fluid to drink when you are sweating is water. I haven’t seen salt tablets used since the 80s; taking salt tablets may raise the body's sodium level to hazardous levels. Although there is some salt in perspiration, you don't really lose that much with your sweat, except in special (usually pathological) circumstances. As prevention is always the best method, have your guys eat their salt, sugar and cocoa packet with every meal and wash down with a quart of water (cocoa has potassium). Putting any kind of sport drink in the canteen or camelback is a bad idea. Things will grow in the sugar residue, especially in the jungle. Nalgene bottles work pretty well; have them flip a couple of spoonfuls in their mouths occasionally. Gatorade is the most reasonable price; make certain to cut it first. Remember, significant hyponatremia can result from voluntary overhydration and can be dangerous.

As for heat stroke, just remember that hyponatremia and significant dehydration are not always associated. Heat stroke usually results from total hypothalamic failure; the body can’t regulate, the temperature rises rapidly, the sweating system fails and the body cannot cool down. Cool them down, but go easy on the fluids with these casualties.

It’s a jungle out there.

It is common these days for guys to gulp down as much isotonic drinks and gatorade than water after a long day in the sun especially when walking along old logging roads with little or no shade for 20-30 kilometers. Its a killer.

Thanks for your advice..much appreciated

[Doczilla]

We've moved away from salt tablets in preventing/treating heat casualties. SouthernDZ is exactly right in everything that he said. It is important that the soldier/potential patient continues to maintain adequate salt intake, particularly when water intake exceeds 4L/day. MREs have adequate salt content, so it's important to emphasize the need to eat their meals. They can't just drink and not eat anything. Monitoring urine output is a good way to monitor hydration status. The darker the pee, the more dehydrated they are. If they are humping for 8 hours without urinating once, they are dehydrated.

Forced water hydration, particularly more than 4L in a few hours, can potentially lead to hyponatremia (decreased sodium level), especially if there hasn't been adequate salt intake. Gatorade and Powerade are highly engineered drinks which provide some amount of sodium to prevent hyponatremia from overaggressive free water hydration. Gatorade has about 2x the sodium of Powerade, and about the same amount of potassium. Gatorade Endurance has double the amount of sodium and 3 times the amount of potassium of regular gatorade. I'd probably cut this latter formula with water.

Other than that, prevention of heat casualties relies on appropriate clothing, frequent rest breaks, protection from the sun, and early intervention on any illnesses that could potentially worsen dehydration, such as nausea, vomiting, diarrhea, fever, or infection. Make sure they drop their gear and fan themselves off frequently. In that weather, with lots of gear, drop for 10 minutes twice an hour.

Prevention and early recognition is key. As the casualty becomes nauseated, dizzy (particularly on standing), fatigued, suffers performance decrement, is confused, has difficulty thinking or solving problems, begins stumbling, is making poor decisions, is thirsty, has a high heart rate not related to exercise, they are dehydrated and potentially hyperthermic, and you should intervene. A high heart rate and no sweating in a confused or obtunded casualty means heat stroke, and they need to be cooled immediately and aggressively. As long as the casualty can drink and won't throw it up, you don't need an IV. Drink in small quantities as a time to prevent vomiting.

'zilla

Edit: hypERthermic, not hyPOthermic. My bad.

[hoot72]

Originally Posted by Doczilla

We've moved away from salt tablets in preventing/treating heat casualties. SouthernDZ is exactly right in everything that he said. It is important that the soldier/potential patient continues to maintain adequate salt intake, particularly when water intake exceeds 4L/day. MREs have adequate salt content, so it's important to emphasize the need to eat their meals. They can't just drink and not eat anything. Monitoring urine output is a good way to monitor hydration status. The darker the pee, the more dehydrated they are. If they are humping for 8 hours without urinating once, they are dehydrated.

Forced water hydration, particularly more than 4L in a few hours, can potentially lead to hyponatremia (decreased sodium level), especially if there hasn't been adequate salt intake. Gatorade and Powerade are highly engineered drinks which provide some amount of sodium to prevent hyponatremia from overaggressive free water hydration. Gatorade has about 2x the sodium of Powerade, and about the same amount of potassium. Gatorade Endurance has double the amount of sodium and 3 times the amount of potassium of regular gatorade. I'd probably cut this latter formula with water.

Other than that, prevention of heat casualties relies on appropriate clothing, frequent rest breaks, protection from the sun, and early intervention on any illnesses that could potentially worsen dehydration, such as nausea, vomiting, diarrhea, fever, or infection. Make sure they drop their gear and fan themselves off frequently. In that weather, with lots of gear, drop for 10 minutes twice an hour.

Prevention and early recognition is key. As the casualty becomes nauseated, dizzy (particularly on standing), fatigued, suffers performance decrement, is confused, has difficulty thinking or solving problems, begins stumbling, is making poor decisions, is thirsty, has a high heart rate not related to exercise, they are dehydrated and potentially hypothermic, and you should intervene. A high heart rate and no sweating in a confused or obtunded casualty means heat stroke, and they need to be cooled immediately and aggressively. As long as the casualty can drink and won't throw it up, you don't need an IV. Drink in small quantities as a time to prevent vomiting.

'zilla

Thanks Zilla

Much appreciated there..great amount of information there which will be extremely helpful...thanks once again guys!

[kachingchingpow]

Good info guys. Coaching youth football has it's hazards, particularly in the south where the temps are in the high 90's when practice starts. It breaks my heart every summer for the couple weeks of practice when a news story airs about some 13 or 15yo kid dying during practice. I think there were several in the state of GA last year alone. I can't emphasize enough to parents how to hydrate their kids off the field. I'll be incorporating some of the language in this thread into our notes to parents.

[SouthernDZ]

The only thing I can add to the expert advice Doc has already imparted is that you need to get to know your team. If any have had heat injuries (or cold injuries for that matter) in the past, they will always be susceptible.

[kachingchingpow]

Re: susceptibility... What causes that btw? Is there a clinical reason, or just common sense? I've always been told that, and have passed that on, but it's always something that someone asks me "how come?"

[Doczilla]

I don't know exactly why patients who suffer heat injury once are more likely to have it again. It's more than simply, "he got too hot". The causes of heat injury are multifactorial; to some extent it depends on the individual's physiological mechanisms (high basal metabolic rate, ability to sweat easily, body mass), any intercurrent diseases (infection, neurological disease, skin disease), medications or drugs (antihistamines, caffeine, anticholinergics, stimulants), and behavioral issues (not taking the time to acclimatize, not taking preventive measures, not paying heed to his body's warning signs, ramping up physical activity in hot/humid environments quickly rather than working slowly up to the desired activity level). Some of these can be modified or avoided, such as not engaging in strenuous exercise in hot environments while being treated for certain diseases. Others are difficult to change or even predict. It's likely that many of the factors that lead to the heat injury will still be there the next time.

In young healthy recruits, poor education on the subject, poor preparation, and poor acclimatization are most often the culprits. Fortunately these can be modified. With proper education and preventive measures, along with acclimatization (usually requires and hour or two of activity in the heat per day over a week, with gradually increasing intensity), the heat injury may be avoided. They can't expect to get off the plane from Minnesota at Ft. Bragg in June and go for a 5 mile run without having some fellas drop out.

Something I forgot to mention in my previous post (but is probably intuitive to most here) is that pre-hydration in anticipation of strenuous activity in the heat is important. If you know your guys are going out in the heat today, start them off right with a couple of cups of water or sports drink before they go. Obviously not RIGHT before they head out the door (because of cramping), but an hour or two.

'zilla

[x SF med]

Originally Posted by kachingchingpow

Re: susceptibility... What causes that btw? Is there a clinical reason, or just common sense? I've always been told that, and have passed that on, but it's always something that someone asks me "how come?"

kccp-
It's thought that the recurrence of Heat and Cold injuries is due to changes in the hypothalmus brought about by the extreme changes to the body during the injury itself - in cases it's been noted that high fevers will make individuals more susceptible to heat and cold injuries for the same reason. Minor damage to the hypothalmus (the body's thermostat among other things) seems not to repair itself very easily.

[hoot72]

Originally Posted by x SF med

kccp-
It's thought that the recurrence of Heat and Cold injuries is due to changes in the hypothalmus brought about by the extreme changes to the body during the injury itself - in cases it's been noted that high fevers will make individuals more susceptible to heat and cold injuries for the same reason. Minor damage to the hypothalmus (the body's thermostat among other things) seems not to repair itself very easily.

Minor damage to the hypothalmus (the body's thermostat among other things) seems not to repair itself very easily.


Could you give some examples of how the Hypothalmus could be "damaged" and have a problem repairing itself? Sorry to ask a silly question.

[Surgicalcric]

Originally Posted by hoot72

...Could you give some examples of how the Hypothalmus could be "damaged" and have a problem repairing itself?

Heat stroke, hypothermia, CVA(stroke), and tumor are a few I can think of off the top of my head...

Crip

[SouthernDZ]

Originally Posted by hoot72

Minor damage to the hypothalmus (the body's thermostat among other things) seems not to repair itself very easily.


Could you give some examples of how the Hypothalmus could be "damaged" and have a problem repairing itself? Sorry to ask a silly question.

From what I’ve read, circulatory collapse and metabolic acidosis which accompanies profound heat injuries, predisposes tissue to hyperthermic injury and, as a result, substantially lowers the threshold for heatstroke injury and mortality. This damage can result in a wide range of effects, from inability to regulate body temperature, appetite and hormonal and emotional disturbances.

I never was on an ODA that had two 18Ds; that sometimes made me the sole voice of reason among raving “type A personalities” who would just as soon treat a GSW by rubbing dirt on it. The Rangers were just as bad, where “pain was weakness leaving the body.” When your people go for their physicals, go with them and (without apologies) sit down and read their health record cover to cover right in front of them. If they have past heat/cold injury, STDs (unless an officer, they get NSUs), allergic-type reactions or are taking any medications and you don’t know about it – follow your rucksack out into the hallway.

There are rarely any questions that are "silly questions"

[kachingchingpow]

Thanks everyone... this is the kind of information I love.