You're about 5 miles up a steep narrow river canyon, off trail, with a buddy (or by yourself). No phone signal for miles. You get bit by a rattlesnake. What do you do?
Remember, the snake doesn't want to eat you, so unless it mistook you for prey or felt unusually threatened, it probably didn't waste any venom. Get away from the snake, or let it get away from you. There's only one antivenin available in the US for pit vipers (https://pubmed.ncbi.nlm.nih.gov/11174237/) so identification isn't that important. If it's in the States and it's not some exotic something, the only other thing it would be is a coral snake, and you really should be able to recognize that. Besides, you'd almost have to stick your hand in its mouth to get a coral snake to bite you. They aren't that big and they're not especially aggressive. So, now that you're a safe distance away from the snake, take stock of your situation. Do you have a PLB or any other signaling device? Use it! (And remember, three of anything is a distress call... bang on an empty fuel bottle, pot, etc three times, wait a minute, do it again, wait another minute and do it again... listen for a response.) Do you have a cell phone? If you have any signal at all send a text message to your emergency contact. Keep it short... "Dial 911" should suffice. Texts go through when calls won't, sometimes. They do know where you were going, right? Then send another short text with precise location if you know it. And another that just says "snakebite" so EMS knows what they're dealing with. Remove any constrictive clothing, jewelry, etc, especially near the bite. Pay attention to how the area around the bite looks. Is there swelling? Burning pain? Discoloration? All indicate venom. If you don't have any of those within a few minutes, you probably didn't get any venom in you. You still need medical attention because snake bites can also become infected, but you're probably fine. Severe swelling and discoloration? Hope someone comes to your rescue and in the meantime find comfort in the fact you have a will and your affairs are in order. No will, you say? Then write one!
I carry a SPOT when I'm really "out there", but in most areas a good whistle is probably better. If there are other hikers in the area, they can probably get to you more quickly and EMS usually isn't going to fly you out without doing an assessment... you're waiting for someone with some authority to hike in, do the assessment, and request medevac. So, better to get help immediately and get moving. That's not to say I wouldn't hit the button on my SPOT if I have it with me... just that I'd be blowing that whistle too.
stay calm, break out your snake bite kit. I always carry my (Sawer extractor) in snake country. After use, check for cell phone signal. If you can’t call for assistance move slowly and calmly towards help or a cell signal.
Excellent question and outstanding follow-up discussion, thank you to everyone who's weighing in on this! I've actually had this on my mind for a few weeks now and saw a pretty good sized rattlesnake just yesterday that brought it to the forefront of my mind (I saw it as I was heading out to the woods for a bit). Really don't have a good plan other than try to get a picture of the snake, get comfortable, make a quick assessment (pain, swelling, discoloration, nausea, etc.) and get help. I carry a cell phone and a Garmin InReach mini, so I'd probably be trying both.
I once attended a talk by a physician who discussed his experience treating about fifty snake bite cases. Half of these weree young children playing around building, often their residence. These bites were frequently on the trunk or face, not extremities and presented a challenge.
The rest were young adults, deliberately messing with the snakes. No hikers involved....
Again, quoting from Medicine for Mountaineering and Other Wilderness Pursuits, "less than one percent of poisonous snake bites in this country [USA] are lethal." definitely not a traveler's manual..
Be alert and be aware in snake country, but also be mindful of other more significant hazards....
I guess MfM has really changed in the newer versions! Mine is all about expedition scenarios... water treatment, altitude sickness, burns, etc, with an emphasis on long-term treatment (well, medium-term), because help is a long ways away! Lots of references to drugs that you just can't get in this country, too.
I had a few close calls as a child... enough that I learned to keep my eyes open!
Those topics are still in the book it goes well beyond first aid. Incidentally, I had occasion to meet Dr. Wilkerson a few years ago - at the Advance Base Camp on Denali, altitude 14,400 feet. I was a member of the NPS mountaineering patrol assisting climbers with problems. On the day, fully acclimatized, we were set to make a summit attempt which was disrupted when a climber at a higher camp came down with severe altitude sickness. We attended to him while Dr. Wilkerson monitored and observed our procedures. Later we discussed the situation, a most positive and enlightening experience.
The procedure was simple - descend!! Barely able to stand at 17,000 feet, he was coherent at ABC and got better as he descended. A few days later, we broke camp ourselves and descended, never mounting another summit try. But the experience with Dr. Wilkerson was far more unique and well worth it
But i never got to wear the summit suit I had picked up at the Anchorage REI (sob!!)