Thane, did not realize the severity of your situation. Hope heat dehytration is the extent of it.
After an earlier reading of your condition, opted to add additional gallons of water to the rig for an upcoming trip.
Now adding coconut water as well.
Listen to the doctors and heal up fast.
Does this postpone the scheduled knee surgery?
Jan
Yes, the knee surgery is indefinitely postponed, though I will likely push hard to get it done this calendar year since my Out of Pocket maximum has very easily been reached.
best bet for EVERYONE: if it’s above 92 degrees (35 c) don’t go. If it’s a 20mph wind and dry, don’t go. If you MUST go, wear your full jacket and pants and put the bag of ice inside your jacket. Simply put, it is IMPOSSIBLE to keep up with evaporative losses in high temp, low dew point and high winds.
Illegitemi non carborundum est!
best bet for EVERYONE: if it’s above 92 degrees (35 c) don’t go. If it’s a 20mph wind and dry, don’t go. If you MUST go, wear your full jacket and pants and put the bag of ice inside your jacket. Simply put, it is IMPOSSIBLE to keep up with evaporative losses in high temp, low dew point and high winds.
I hate to say, I told you so, but......well.....you know 
Two Million Mile Rider
Exploring the World in Comfort
Thane, best wishes and prayers for a fast recovery. Sheesh, that does not sound like fun, at all! Maybe I can talk my sister into sneaking you some ice cream when the nurses aren't looking!
Regarding heat riding.
All of what FM says is true in his first post in this thread. However, I find that building up a tolerance to heat is also somewhat possible.
I regularly ride over 110F (not mph), and do a lot of the steps mentioned. I kind of like my Aerostitch suit (rotten banana look) for those rides, where I can have wicking stuff on underneath, but not much else. Keeping it closed, with the exception of the sleeves open wide and the back vents, seems to keep just enough airflow over wet base layers to act as air-conditioning for about an hour at a time, then resoak stuff down and proceed for the next hour.
If it is just a couple hour ride, then usually the top layer is a light colored Carhart canvas long sleave shirt and light colored ripstop pants, without soaking.
I think the heat tolerance buildup comes from working in a 105F garage for extended periods, and keeping the house AC at 80 F. The 80 F has become very comfortable, after the first year. The 105 F garage is tolerable for long periods, now. When an old friend, coincidentally from Nebraska, joined me in the garage to work on an ATC project a couple weeks ago, the 105F was pretty hard on him; he had to take some breaks in the AC to survive.
Of course, proper hydration is critical. Drink more than you think you should, sooner than you think you need to. If you get thirsty, it is already late in the game.
Always carry an extra gallon of water, just in case...
Rotten Banana suit:
