You Can't Silence Us

One of the things that makes the heat so dangerous here in Florida is the humidity. The dew point temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. At 100% relative humidity, the dew point temperature and the air temperature are the same, and clouds or fog can begin to form. While relative humidity is a relative measure of how humid it is, the dew point temperature is an absolute measure of how much water vapor is in the air (how humid it is). In very warm, humid conditions, the dew point temperature can reach 75 to 77 degrees F, but rarely exceeds 80 degrees.

The dewpoint for the afternoon that caused my heatstroke was between 71f and 74f. The temperature for that 4 hour period was between 91f and 94f. That results in a heat index of between 100f and 103f.

High dewpoints are dangerous because it is a limit on how well your sweat can evaporate and cool your body. Heat can build up to dangerous levels.

Combined with that, it was a bright, sunny day with almost no wind. The Navy actually has tables for permissible heat exposure. Under those conditions, Navy regulations say that acclimatized personnel shouldn’t perform heavy work for more than 15 minutes per hour. I far exceeded that for more than 4 continuous hours.

Even worse, I am now 35 years older than I was when I was in the Navy. I am also about 40 pounds heavier. All of that makes my susceptibility to heat stress more pronounced.

As I said, I know better. Let my experience in this case serve as a warning to others as we enter the hot summer months here in the South.

It’s been several days since my last post. There is a good reason for that. As my readers know, I am installing a pool in the backyard. It’s almost done, and I decided that this was the best time to install the landscape sprinklers. I rented a gas powered trencher and spent a day pushing that thing around the yard as it dug a few hundred feet of foot-deep trenching.

I thought the trencher would make the job easy, and it didn’t. It made the job easier and faster, but it was still a chore trying to maneuver that thing all over the yard. It was hot, and by hot, I mean 95f with dew points around 70f. That’s a heat index of about 102f. I drank four quart sized bottles of Gatoraid during the six hours I was working. When it was time to return the trencher, my wife came with me and we went to dinner afterwards.

At dinner, I began losing my words. It started when I tried to say “skin in the game” and what came out was entirely different. Then I couldn’t really hold a train of thought long enough to continue our conversation. When we tried to leave, I was walking like I was drunk. My wife drove us home. When I got home, I was feeling confused, my pulse was 125, and temperature was 101.9f. I asked her to take me to the ED.

When we got there, the staff thought the same thing that I did- they put me under the sepsis protocol. Another oddity was that my right ankle was swollen to twice its normal size and extremely painful. My vital signs were odd:

Pulse 120, respirations 28, Oxygen Saturation 98%, BP 145/110, temp 99.8f

They also tested my heart, did a CT scan of my brain, and a bunch of other tests. The results that were abnormal was my D-dimer, which was critically high at 1.02, as well as my creatinine levels and liver enzymes were elevated. It looked like my kidneys and liver were being damaged somehow.

For those who don’t know, d-dimer is a protein that is found in the blood of someone after the breakdown of widespread blood clots. Elevated D-dimer levels suggest increased fibrinolysis, which can be a sign of either clotting or bleeding.  Now they got really concerned that I had blood clots, which can cause swelling legs, strokes, heart attacks, and other problems. The decision was made to admit me at that point. I went back to CT for an angio scan.

All of the tests of my heart, brain, and other systems came back normal. That d-dimer still bothered everyone. Finally, the hospitalist came to see me the next morning with what we all agreed was the answer. The combination of fluid loss due to my large amount of sweating, as well as the elevated core temperature from strenuous outdoors work cause a severe case of heat stroke, which activates your body’s clotting mechanisms, causing widespread micro blood clots.

Studies have shown a correlation between elevated D-dimer levels and the severity of heatstroke, as well as with the development of complications like AKI (acute kidney injury). In patients with exertional heatstroke, high D-dimer levels are associated with an increased risk of acute kidney injury. This in turn causes hyperinflammation (hence, the swollen ankle).

The danger here is that I was on the verge of developing disseminated intravascular coagulation (DIC) and multiorgan failure, which would have killed me. I didn’t even feel bad while I was working, and I thought that drinking large amounts of fluids would keep me from being dehydrated. I was wrong. I lost 12 pounds in that six hour period when I was working. When you consider that I drank about 12 pounds of Gatoraid, that means I lost about 12 liters of sweat in those six hours. Sweating out 24 pounds of fluid in an afternoon is potentially deadly. I am fortunate to be alive.

In short, I had an extremely severe case of heat stroke, and it damned near killed me. I wound up being in the hospital for several days. It was stupid of me not to recognize the signs and symptoms, especially as a nurse, a paramedic, and as someone who has lived in the Florida heat nearly his entire life. I was supposed to work today. I called off. I still feel a bit weak and under the weather, and my ankle still hurts.